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Do Tilted Domes Suck?

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  • KDConod
    ... I may be in a position to design a theater in the next couple of years. It d have a traditional star projector in the middle (we d move it from our current
    Message 1 of 17 , Aug 3, 2004
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      >A 22.5 degree tilt and seating generally facing
      >the lowest portion of the dome. You want to
      >provide an eye level horizon line to at least
      >part of the audience. Having part of the scene
      >behind you which you don't see also provides
      >more options when planning camera moves
      >to 'reveal' things from beyond the 'frame' as one
      >does with other forms of cinema.

      I may be in a position to design a theater in the
      next couple of years. It'd have a traditional
      star projector in the middle (we'd move it from
      our current theater to the new one).

      Although the star projector could be modified to
      sit in a tilted dome, I'm hesitant. Fact is I
      don't particularly like tilted dome theaters.
      Although they may be nice for an eye level
      horizon (for how much of the audience? I often
      find myself looking down in Imax Dome theaters),
      that's not going to matter much to the 85 year
      old woman who's lying in a heap at the bottom of
      the stairs or to the mother who's struggling to
      get out of a darkened theater with a screaming
      kid or the handicapped person sitting either the
      last row or first row. That's not to mention the
      folks who won't even sit in the theater because
      of the vertigo it induces!

      Is it just me?


      =====
      Kevin Conod
      kdconod@...
    • Ed Lantz
      ... On one end of the spectrum there are modern theaters such as the Fels Planetarium at the Franklin Institute with a level dome and removable
      Message 2 of 17 , Aug 3, 2004
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        Kevin Conod writes:

        >...I don't particularly like tilted dome theaters. Although they may
        >be nice for an eye level horizon (for how much of the audience?
        >I often find myself looking down in Imax Dome theaters), that's not
        >going to matter much to the 85 year old woman who's lying in a
        >heap at the bottom of the stairs or to the mother who's struggling
        >to get out of a darkened theater with a screaming kid or the
        >handicapped person sitting either the last row or first row. That's
        >not to mention the folks who won't even sit in the theater because
        >of the vertigo it induces!

        On one end of the spectrum there are modern theaters such as the Fels
        Planetarium at the Franklin Institute with a level dome and removable
        (unidirectional) seats. Works ok as a planetarium, plus a great venue
        for a banquet, wedding or dance party with its level floor. Long shows
        are hard on the neck, though, without reclining chairs.

        Midway there are slightly tilted domes (7-15 degrees) that generally do
        not have the problems that Kevin laments. Many new Spitz theaters use a
        10 degree tilt - no vertigo problems at all. The BCC planetarium in
        Cocoa is very comfortable with a 12 degree tilt. Still a problem with
        handicap access in some cases, but not too hard on the brain to
        navigate.

        Then there are the combo planetarium-film theaters (and new fulldome
        theaters) with 20-30 degree tilt. Yes, this tilt can cause vertigo and
        can be difficult to navigate. The rows are steep and there is little to
        keep a person from tumbling other than the high backs of the seats on
        next row down (which create a barrier that is sometimes only 1 foot
        high). The visual experience is usually quite nice, however, since you
        do not have to lean back to be fully immersed (unless you sit in the
        front row, which are poor seats in all theaters).

        I don't think anyone would say that one type of theater sucks and
        another type is ideal. They all have a certain character. Fortunately,
        it doesn't much matter to fulldome show producers - provided everyone is
        unidirectional. Concentric theaters are another beast altogether.
        Still, the AMNH Hayden has done a great job distributing their
        omnidirectional shows to uni theaters (it likely cannot work the other
        way around, though).

        I have a design for a convertible theater that can operate as a tilted
        dome with stadium seating, yet can convert to a level dome with a level
        floor for other events. Perhaps that is the way to get the best of both
        worlds?

        Ed
        ed@...
      • Schmidt Mickey D Civ 34 ES/BAWL
        All, For what it is worth, in regards to dome tilt. I don t think thay suck. Let me be the first to say that I have no personal experience of producing a
        Message 3 of 17 , Aug 3, 2004
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          All,

          For what it is worth, in regards to dome tilt. I don't think thay suck. Let
          me be the first to say that I have no personal experience of producing a
          presentation under a tilted dome. I can say I have always wanted to.

          The level dome at the USAF planetarium has a spring-line 9' above the floor.
          I have been using it for 25 years and deperatly would have liked a tilted
          dome to bring the horizon down to eye level. I have not determined if 15, 20
          or more degrees is an optimum value. I have seen the steeply tilted dome at
          Grand Forks in North Dakota. I thought that was a bit too much tilt.

          The dome at the planetarium facility at Fairchild AFB, near Spokane
          Washington does reflect influence I had some input on. I don't know the
          abount of tilt of the main dome but the unique situation there required E&S
          to modify their projector arrangement to bring visuals down to eye level. It
          could work with or without a tilted dome. The down side is that the
          additional graphics projected below the basic spring line requires an
          additional projector.

          The idea was developed here at the USAF Academy planetarium because I knew
          that I would never have a tilted dome in the current facility. So the idea I
          had was to create an area in front of the audience of a simple curved screen
          from the base of the dome to the floor. The width at the USAFA Planetarium
          would have been about 90 degrees.

          I figured the images shown on that part of the "screen" would be the
          foreground images below the natural horizon. (Landscape, seascape etc.)
          Alas, I have not been able to see that "experiment" applied at the Air Force
          Academy but if there are any readers with experience with the Fairchild AFB
          SERE Training School please report on that application. Is it advisable to
          repeat or not? Perhaps readers from Evans & Sutherland who installed the
          current system (D3) might have some remarks, good or bad, about keeping a
          level or slightly tilted dome and adding an extension to allow for
          foreground images.

          Keep the knowledge flowing.

          Mickey

          Mickey D. Schmidt, Dir.
          USAF Academy Planetarium
          Battlespace Awareness Warfighting Laboratory
          USAF Academy, CO 80840
        • Tom Casey
          ... I ll have to say my feelings are edging somewhat towards this feeling as well... but not for some of the reasons mentioned here. My biggest concern is
          Message 4 of 17 , Aug 3, 2004
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            Kevin Conod wrote:
            >That's not to mention the folks who won't even sit in the theater because
            >of the vertigo it induces!

            >Is it just me?

            I'll have to say my feelings are edging somewhat towards this feeling
            as well... but not for some of the reasons mentioned here. My
            biggest concern is that we are turning the planetarium dome into
            something similar to the now defunct format, Omnimax. The immersive
            feel of a flat or close to flat dome is really what our business is
            all about, but what I see happening is a trend/fad to go to these
            tilted versions. It's a nice looking theater and there are some
            pluses for some types of visual material, but we are loosing
            something important...

            To explain where I am going just watch the audience in a flat dome
            versus a tilted one. In a tilted one the audience will lean back and
            look forward at the "sweet spot" and NEVER move their heads... you
            see a good deal of the dome in this position so why expend the effort
            to look around. I've noticed that a LOT of content is aimed at this
            presentation... where all the action occurs forward and you spend
            most of your time just zooming past things forward facing. Is this a
            result of the tilted dome or are we as content creators missing the
            point and loosing the grand effect of the immersive fulldome feel.
            (Sometimes this is caused because we create in the blind without a
            dome to view our content as we create... it was the hardest thing my
            animators had to learn... to use the entire dome.)

            I know it is harder to create something that makes the viewer want to
            look around, but isn't that the thing we have and that makes us
            different from the other mediums, as Ben Shedd would say, "frameless"
            views.

            A dome that is not tilted (or less than 10 degrees) almost forces the
            audience to learn to look around (you can't see as much looking just
            forward) and with the help of the content creator who understands the
            fulldome view, they will learn to enjoy this difference from other
            presentations.

            My 9 year old who has never seen a fulldome show in a tilted dome has
            learned to look around during a show... he's looking over my shoulder
            now waiting to get back on this computer to play some games...
            reading what I've been writing, he just said, "Why would you want to
            tilt the dome? The sweet part about it is being in the middle of
            what's happening."

            So how do I explain to him why all the new domes are tilted? Got me!

            Tom



            --

            ...................................................................................
            H o m e R u n P i c t u r e s

            Tom Casey
            President and Creative Director
            100 First Avenue, Suite 450
            Pittsburgh, PA 15222
            412-391-8200
            412-391-1772 -fax
            mailto:tom@...
            http://www.hrpictures.com
            ...................................................................................
          • Ryan Wyatt
            ... Once upon a time, I railed against horizontal domes -- and concentric seating. A few people might recall my diatribe after sitting through sessions at IPS
            Message 5 of 17 , Aug 3, 2004
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              After Don effused about tilted domes, Kevin confessed:
              > Fact is I don't particularly like tilted dome theaters.

              Once upon a time, I railed against horizontal domes -- and concentric
              seating. A few people might recall my diatribe after sitting through
              sessions at IPS 2000, when I argued that any concentric planetarium
              hosting IPS should offer all delegates a free massage every evening.
              In the Hayden as well, I find that the seats are not conducive to
              sitting for a long time and viewing angles can be uncomfortable (lying
              down in the middle of the theater is great, but there's this weird
              machine that gets in the way sometimes).

              What I *like* about the horizontal dome (the term "flat dome" never
              made sense to me, although it's used by a surprising percentage of
              people) is that the design creates a shared environment in a way that
              the tilted dome does not. The historical link to the night sky makes
              perfect sense in this context: even when we're showing fulldome video
              in the Hayden Planetarium, it harkens back to the communal experience
              of sitting under the starry sky. And I'll echo Tom's observation that
              people spend a lot of time looking around in this setting, although
              that's sometimes perceived as a negative (even though Tom and I seem to
              like it): one person complained that she didn't know where to look
              while she was watching the show!

              Having had the opportunity to help design shows for a
              horizontal-concentric theater and then convert them to show in the more
              typical tilted-unidirectional theaters, I have to say that the
              experience of watching the "same" material can often be radically
              different. Coming up out of the ocean at the beginning of "Search for
              Life," for example, produces a rush at the Hayden that doesn't quite
              translate to the tilted format (likewise with landing on Mars). The
              flight through the beginning of "SonicVision," on the other hand, has
              an immediacy in tilted domes that it lacks in the horizontal setting
              (however much I like it in both).

              I will say that 30 degrees feels too steep to me; the 22.5 that Don
              recommends falls closer to my preference as well, although I allow
              about a 10% slop, settling for anywhere from 20-25 degrees.

              So... I dunno. I think the tilted dome produces a more optimal "ride"
              experience than the horizontal-concentric setting, but for a more
              contemplative journey (and for a few special effects), the
              horizontal-concentric design has its advantages.

              The way I sometimes describe it is that the highly-tilted
              unidirectional domes are more about the individual experience, while
              the horizontal dome with concentric seating is more about the group (or
              one could claim, community) experience.

              Interesting discussion, folks!


              Ryan, a.k.a.
              Ryan Wyatt, Science Visualizer
              Rose Center for Earth & Space
              American Museum of Natural History
              79th Street & Central Park West
              New York, New York 10024
              212.313.7903 vox
              212.313.7868 fax
            • Ed Lantz
              ... I beg to differ with you, Tom. It is not the dome design that allows/prevents folks to look around, it is the production (as you have alluded to). In
              Message 6 of 17 , Aug 3, 2004
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                Tom Casey writes:

                >In a tilted one the audience will lean back and look forward at
                >the "sweet spot" and NEVER move their heads... you see a
                >good deal of the dome in this position so why expend the effort
                >to look around. A dome that is not tilted (or less than 10 degrees)
                >almost forces the audience to learn to look around (you can't see
                >as much looking just forward) and with the help of the content
                >creator who understands the fulldome view, they will learn
                >to enjoy this difference from other presentations.

                I beg to differ with you, Tom. It is not the dome design that
                allows/prevents folks to look around, it is the production (as you have
                alluded to). In fact, I would argue that, if anything, a steeply tilted
                dome provides the greatest freedom of head motion.

                The degree of immersion in a well-designed theater (with seats that have
                the proper tilt) is largely a function of the distance of the viewer
                from the spring line (measured perpendicular to the plane of the spring
                line). Pull back out of the dome and your field-of-view decreases (such
                is the case in most horizontal domes to accommodate doorways). Push
                into the dome and field-of-view increases. Tilt never enters into the
                equation. If you are staring at the wall in the front of a theater, it
                is because your seat is not tilted back enough. Of course, in a level
                dome, seats must be tilted a lot, especially a unidirectional dome where
                seats often are pushed right up to the dome screen (one advantage of
                concentric seating, along with the "around the campfire" community feel
                as Ryan points out, is that no one is closer than one radii from the
                dome in their forward field-of-view).

                So all things being equal, consider that most viewers sit normally in a
                tilted dome. A highly tilted seat with headrest is not required to
                achieve maximum immersion, since the dome image nearly matches our
                normally seated field-of-view. Without gravity pulling their head back
                onto a headrest, viewers actually are _more free_ to look around. To
                look around in a level dome (or to look at a live presenter), one must
                first pick their head up from the headrest.

                Note that, in a concentric theater, viewers often _must_ look around,
                since the object of interest to everyone in the theater is behind the
                heads of approximately 1/3 of the viewers. Before the AMNH Hayden was
                built, Neal deGrasse Tyson passionately argued that the concentric
                theater is a more natural effect because of the required head motion.
                Perhaps. But when one turns to look at an image behind them in a
                concentric theater, the image is terribly distorted if sitting in an
                outside row.

                Is forcing people to turn their heads a good idea? That is an aesthetic
                issue, to be sure. I can say this - most people will not look around
                for long. Perhaps we are just too conditioned to staring at the boob
                tube, but research has shown that, given the ability to rotate the head
                in an immersive environment, most people gravitate towards looking
                forward after the novelty wears off. Requiring a lot of head motion is
                also fatiguing. One extreme example of head rotation is the film R&J
                from DomeFest. One scene has a character directly behind the audience's
                head. That was actually painful! Certainly some eye motion is fun, and
                an occasional head-turner is a welcome surprise for me, especially when
                given some sort of cue to turn my head (a flash of light, an object that
                leads my eye over to one side, surround audio cue, etc.). So I agree
                with Tom that we should be challenging viewers a bit more, but it can
                easily be overdone.

                Great discussion. Back to work now.

                Ed
                ed@...
              • Ryan Wyatt
                ... Well, that s a bit of an exaggeration. We tend to compose more for the zenith, and horizon shots can be composed quite democratically. If 33% of the main
                Message 7 of 17 , Aug 3, 2004
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                  Ed noted:

                  > Note that, in a concentric theater, viewers often _must_ look around,
                  > since the object of interest to everyone in the theater is behind the
                  > heads of approximately 1/3 of the viewers.

                  Well, that's a bit of an exaggeration. We tend to compose more for the
                  zenith, and horizon shots can be composed quite democratically. If 33%
                  of the main focus were behind people's head, then you could think of
                  33% of the main focus being behind you for any given seat (and a
                  democratically designed show). But I'd say much less than 10% of
                  "Search" (namely, the Mars flyover) and almost none of "Passport" is
                  designed so that you end up with the main point of interest directly
                  behind you. Even when something appears behind you, it moves quite
                  quickly to a range within your comfort zone.

                  So, it's a challenge, but composing for concentric seating can actually
                  work quite well...

                  When we re-compose for a tilted dome, we then have to choose a point of
                  interest and rotate all our imagery to point toward it, though! :)
                  And then change horizon lines to accommodate the tilt; fortunately, the
                  brain is very forgiving on that front, so we don't need to create
                  10-degree, 20-degree, and 30-degree versions of the show. We actually
                  re-rendered portions of "Search" to maintain resolutions when we re-did
                  it with tilt.

                  > But when one turns to look at an image behind them in a concentric
                  > theater, the image is terribly distorted if sitting in an outside row.

                  No doubt about that!


                  Ryan, a.k.a.
                  Ryan Wyatt, Science Visualizer
                  Rose Center for Earth & Space
                  American Museum of Natural History
                  79th Street & Central Park West
                  New York, New York 10024
                  212.313.7903 vox
                  212.313.7868 fax
                • Grant.Nicholson@ipaustralia.gov.au
                  Folks, It seems to me that the reason for wanting a tilted dome is to bring the horizon line down to level with or below the natural sight line of the audience
                  Message 8 of 17 , Aug 3, 2004
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                    Folks,

                    It seems to me that the reason for wanting a tilted dome is to bring the
                    horizon line down to level with or below the natural sight line of the
                    audience and thus enhance the immersive experience. Could this not be done
                    with a flat dome which has the spring line at or below shoulder level of
                    the audience?

                    I know there is a technical problem here... all standard projector
                    configurations throw their image across the volume of the dome (from the
                    centre or the edge) to the other side and would thus face problems of human
                    heads getting in the way. But if this technical problem could be solved
                    (different projector configurations, rear projection, active domes etc.)
                    then the dome could be flat as well as highly immersive.

                    I think the ideal arrangement would be a flat dome with the spring line at
                    average shoulder level of the audience (I assume some seat raking would be
                    desirable) with an extension to the front of the dome. This extension would
                    take the front of the screen to floor level or below without the need for
                    raising the back of the dome.

                    This would allow the screen to effectively be both tilted and flat and more
                    fully immersive than existing tilted domes.

                    The idea of alternate projection methods that would allow such radical
                    lowering of the dome screen may be dismissed by some, but I guess people
                    once said similar things about full dome video and digital star projectors.

                    Just my 2c worth.


                    Cheers,

                    Grant Nicholson
                    President - Sydney Sky Theatre Development Association
                    Australia
                  • Ed Lantz
                    ... Ahhh yes, there is always the zenith in a concentric theater. I recall the Laserium shows that used abstract imagery centered on the zenith. it didn t
                    Message 9 of 17 , Aug 3, 2004
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                      I wrote:

                      >> Note that, in a concentric theater, viewers often _must_ look around,
                      >> since the object of interest to everyone in the theater is behind the
                      >> heads of approximately 1/3 of the viewers.

                      Ryan points out:

                      >Well, that's a bit of an exaggeration. We tend to compose more for the
                      >zenith, and horizon shots can be composed quite democratically. If 33%
                      >of the main focus were behind people's head, then you could think of
                      >33% of the main focus being behind you for any given seat (and a
                      >democratically designed show). But I'd say much less than 10% of
                      >"Search" (namely, the Mars flyover) and almost none of "Passport" is
                      >designed so that you end up with the main point of interest directly
                      >behind you. Even when something appears behind you, it moves quite
                      >quickly to a range within your comfort zone.

                      Ahhh yes, there is always the zenith in a concentric theater. I recall
                      the Laserium shows that used abstract imagery centered on the zenith. it
                      didn't really matter where one was seated (well not completely. folks
                      "in the know" always said the best seats were near the laserist because
                      you had the same vantage point as the person composing the show).

                      So to add another chapter in our fulldome primer tome (which, as David
                      McConville aptly points out, will soon be lost to the ethers), one can
                      navigate an audience up and down in unison in a concentric theater, and
                      fly objects around and over the audience. However, horizontal terrain
                      flyovers will leave half (one third?) of the audience flying backwards.
                      Also characters and text will appear upside down or sideways to nearly
                      half the audience if placed at the zenith. If placed on the horizon
                      they will be obscured to a large portion of the audience unless repeated
                      or rotated around the dome.

                      AMNH has done a great job playing to the sensitivities of concentric
                      fulldome show production (and in the conversion of concentric shows to
                      tilted unidirectional). To be sure, concentric theaters have a very
                      special feel along with some serious limitations. I like the "sitting
                      around the campfire" feeling. However, even a star party would have
                      most folks facing the same direction if someone was pointing out
                      constellations, so I fail to buy into the argument that it is better
                      suited to night-sky presentations or astronomical material. Ultimately
                      there is no right and wrong way to design a theater.

                      Steve Cooper writes:

                      >The real way to improve the visitors field of view is to use every
                      >trick you can to move them to the 'back' of the big round room.
                      >More dome real-estate opens up by taking two steps back than by
                      >tilting the dome any-day.

                      If you think about it, Steve, moving to the back of the theater only
                      "remaps" the hemispheric imagery. The area of the retina that is
                      covered by imagery, the actual field-of-view (FOV) of the dome screen on
                      the eyeball, remains about the same. If you sit on the back wall, for
                      instance, the +/- 90 degree points on the dome (east and west) are now
                      compressed into a visual FOV of only 90 degrees for that viewer. These
                      points should actually appear to your extreme left and right with 180
                      degrees of separation. In other words the image is terribly distorted.
                      Fortunately the brain doesn't much seem to care. Brad Thompson actually
                      pre-distorts his rendered images (using a Glom feature called eyepoint
                      offset) to make the images look proper to viewers sitting slightly
                      behind dome center, since the majority of seats are clustered there.
                      Not sure what that does to folks in the front seats, though..

                      >The shallower tilt allows for a better Skies show. If Skies shows
                      >and Space related presentations are your driving force, there is
                      >no excuse for a steep tilt. On the other hand, if your primary
                      >goal is immersive 'take you there' experiences, or just knock them
                      >out of their socks rides, then the steeper tilt accomplishes that.

                      Are you implying that "space related presentations" should not be
                      knock-your-socks-off, 'take you there' experiences?

                      Sorry to pick on you... Your new facility sounds like a cutting-edge
                      experiment - looking forward to it, and best of luck!

                      Ed
                      ed@...
                    • Ryan Wyatt
                      ... Right... Which is like the initial Mars approach in Search (where we see only a limb of the planet), but then, once it becomes a full panorama, a
                      Message 10 of 17 , Aug 4, 2004
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                        > However, horizontal terrain flyovers will leave half (one third?) of
                        > the audience flying backwards.

                        Right... Which is like the initial Mars approach in "Search" (where we
                        see only a limb of the planet), but then, once it becomes a full
                        panorama, a well-designed flight path simply leaves one with a sense of
                        motion that doesn't necessarily feel backward or forward.

                        > Also characters and text will appear upside down or sideways to nearly
                        > half the audience if placed at the zenith.

                        Which is why we basically don't use text in the dome... (Plus, it
                        needs to be translated for distribution!)

                        > If placed on the horizon they will be obscured to a large portion of
                        > the audience unless repeated or rotated around the dome.

                        This was our solution for "Passport": three images placed 120 degrees
                        apart on the dome. We've also scrolled text horizontally around the
                        circumference of the dome.

                        The biggest drawbacks of unidirectional versus concentric seating
                        IMNSHO are the somewhat smaller field of view and the general
                        discomfort of sitting for a long term. Its strengths, on the other
                        hand...

                        > I like the "sitting around the campfire" feeling. However, even a
                        > star party would have most folks facing the same direction if someone
                        > was pointing out constellations, so I fail to buy into the argument
                        > that it is better suited to night-sky presentations or astronomical
                        > material.

                        The didactic excuse I've heard is that people learn the directions
                        better. Not sure I buy that. But I think the important part is your
                        first statement, "I like the 'sitting around the campfire' feeling."
                        It *is* a feeling, a tangible sense of community that one gets in the
                        concentric environment. I wouldn't say "better suited," but I would
                        note that it's a strikingly different environment from a standard
                        theater experience (a benefit, I think), and it also underscores the
                        communal ownership of the night sky -- the idea that the sky belongs to
                        everybody, in the planetarium and in the world.

                        As I say, I'm a bit of a convert, so perhaps I can be forgiven for
                        attempting to proselytize. :)


                        Ryan, a.k.a.
                        Ryan Wyatt, Science Visualizer
                        Rose Center for Earth & Space
                        American Museum of Natural History
                        79th Street & Central Park West
                        New York, New York 10024
                        212.313.7903 vox
                        212.313.7868 fax
                      • Schmidt Mickey D Civ 34 ES/BAWL
                        We wrestled with the problem of circular or concentric seating in the planetarium in the 1980 s. The advantage: - Larger audiences, we could seat 300 people
                        Message 11 of 17 , Aug 4, 2004
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                          We wrestled with the problem of circular or concentric seating in the
                          planetarium in the 1980's.

                          The advantage:
                          - Larger audiences, we could seat 300 people mixed children and
                          adults in the theater.

                          The disadvantages:
                          - Someone was always to your back in a "lights up" presentation.
                          - During "star shows" 1/3 audience had their back to that part of the
                          dome.
                          - It required 3 times the number of visuals so everyone saw equal
                          visuals. 3x the projectors, 3 times the slides.
                          - Production costs and time was increased.
                          - Three times the maintenance and alignment issues.
                          - Fewer seats, with current AF OSHA regulations we now seat 124
                          persons in the chevron pattern. Revenues would be down.

                          We chose to go with a chevron type seating even before we thought about
                          full-dome visualization.

                          Our shows were free so revenue was not the issue. It was an effort to reduce
                          costs and staff. That has now reached its ultimate conclusion as all staff
                          has been eliminated.

                          With Full dome visualization we are free to move the area of interest to the
                          "front" of the room. That may present problems of teaching true placement in
                          the sky with stars and constellations but with images of models we were are
                          free to add motion which brought the image into everyone's line of sight.
                          This would be true of concentric seating as well.


                          Mickey D. Schmidt, Dir.
                          USAF Academy Planetarium
                          Battlespace Awareness Warfighting Laboratory
                          USAF Academy, CO 80840
                        • Ed Lantz
                          Grant Nicholson suggests:
                          Message 12 of 17 , Aug 4, 2004
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                            Grant Nicholson suggests:

                            << It seems to me that the reason for wanting a tilted dome is to bring
                            the horizon line down to level with or below the natural sight line of
                            the audience and thus enhance the immersive experience. Could this not
                            be done with a flat dome which has the spring line at or below shoulder
                            level of the audience?>>

                            Spitz used to make a tilted hyerhemisphere (or hyposphere) that did just
                            that. I would argue, however, that the audience in a populated theater
                            only has somewhat less than a hemispheric field-of-view, and making a
                            dome any more than a hemi is a waste (unless, of course, the starball
                            demands it, which was the case with Spitz). In fact, in most cases, a
                            165 degree dome is ideal, since the dome surface is normal to the viewer
                            (the eyepoint is always somewhat below dome center - best to put dome
                            center at eye level and raise the spring line slightly above eye level,
                            thereby slightly truncating the hemisphere).

                            The dome really shouldn't be lowered to eye level. Consider that when
                            the theater is populated, there are heads to the left, right and in
                            front of you. Any image approaching head level will be obscured by the
                            heads of surrounding viewers. We usually design the theater to account
                            for the case where one is shorter than surrounding viewers (not everyone
                            has the same eye level) so the dome should be slightly above head level.
                            In level domes one must play architectural tricks to get people into the
                            theater when the spring line is only 5' above the floor. In tilted
                            domes this is easier to do, since the dome already spans two or more
                            floors.

                            Tilting the seating deck simply lowers those heads in front, allowing
                            the dome to be tilted down (or extended) in the front to fill the
                            expanded field of view. But the viewer's total immersivity or
                            field-of-view is essentially unchanged because the heads behind you are
                            now higher and block your view in the back (most folks don't mind
                            that...), requiring the dome to be tilted up (or trimmed) in the back.
                            Things on the sides are unchanged regardless of dome tilt. So any way
                            that you look at it, your actual field-of-view when seated with an
                            audience is less than hemispheric.

                            The problem with traditional planetariums is that the spring line is way
                            over people's heads and, what's worse, there is a huge instrument poking
                            up into the sky blocking sight lines to the dome. When designing a
                            fulldome theater that uses a starball, the instrument must be on an
                            elevator so it can be dropped out of people's faces.

                            Now in a home fulldome theater where there is no one sitting in front of
                            you, vertical FOV can exceed 180 degrees. Someone called this "Mymax."

                            Ed
                            ed@...

                            p.s. - if you are putting in a theater of your own, you're best off if
                            you or your architect hires a competent planetarium system integrator or
                            consultant to help you with all these issues. There are very few
                            architects with fulldome theater experience.
                          • Todd Slisher
                            ... Just a quick correction on your previous statement Tom. OmniMax is not a dead format at. Many of these theaters have been rebranded as IMAX Dome in many
                            Message 13 of 17 , Aug 7, 2004
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                              Tom Casey wrote:

                              >My biggest concern is that we are turning the planetarium dome into something similar to the now defunct format, Omnimax.

                              Just a quick correction on your previous statement Tom. OmniMax is not a dead format at. Many of these theaters have been rebranded as IMAX Dome in many cases. You may be thinking of the old 'Cinema 360' format instead. 15/70 mm films are still being produced for these domed theaters, and almost all new large format films are available in a dome version. It is true that some large format distributors are not shooting movies specifically for Domed environments which leads a 'tight shots' problem (images are too close up) but this is a general problem for many starting large format film-makers even for flat screens. (Who really wants to see the zit on the actors cheek on a 5 story high face???)

                              Not many new IMAX theaters are being built with domed screens, but this is more a reflection of the fact that one of the big pushes in this format is 3D films. Domes are not good environments for 3D projectors and film content. Another factor is that many new IMAX theaters are commercial ventures which make use of the new IMAX DMR process to 'blow up' commercial films to IMAX format and size. They are definitely showing films made for the flat screen! This is becoming more an more the push of IMAX corp.

                              IMHO Planetarium full dome has an advantage over IMAX Dome in that IMAX dome only uses about 2/3 of the screen (about the front 120 degrees). Although the immersive feeling is there, the audience is aware of the 'blank' portions of the screen, particularly if they are seated at back of the theater. We actually tell people in our IMAX dome that the front seats are the 'thrill seeker' seats (since you can't see the blank portions of the dome). In addition, in my opinion, IMAX films are so bright that the illumination of the theater from light scatter partially destroys the illusion of 'being there'. You really can't be in the film, if you can see a row of seats beside you.

                              This is actually one of the largest advantages of Full Dome production and feel - the dark environment. This is also why astronomy type shows work well in this environment. Bright fully-lit scenes tend to destroy the very illusion we are trying to create! Although IMAX loves to advertise their 15,000 watt lamps that could be seen from the space station, I'd hate to see this level of illumination in full dome theaters.

                              Utilizing the entire screen along with the dark conditions are two strong advantages of Full Dome Planetarium theaters have over IMAX dome theaters. (that and the lack of $22,000 print costs for film prints).

                              Just some observations from someone with a foot in both worlds these days.

                              Todd

                              Todd K. Slisher
                              Director of Theaters - Space Science
                              Detroit Science Center
                              5020 John R Street
                              Detroit, MI 48202
                              Tslisher@...
                            • Don Davis
                              ... Who has been shooting 15/70 films in recent years? About 30 years ago I traveled to San Deigo to see the initial offerings of the Reuben H. Fleet Space
                              Message 14 of 17 , Aug 7, 2004
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                                >Tom Casey wrote:

                                >>My biggest concern is that we are turning the planetarium dome into
                                >>something similar to the now defunct format, Omnimax.

                                >Just a quick correction on your previous statement Tom. OmniMax is not a
                                >dead format at. Many of these theaters have been rebranded as IMAX Dome in
                                >many cases. You may be thinking of the old 'Cinema 360' format instead.
                                >15/70 mm films are still being produced for these domed theaters, and
                                >almost all new large format films are available in a dome version. It is
                                >true that some large format distributors are not shooting movies
                                >specifically for Domed environments which leads a 'tight shots' problem
                                >(images are too close up) but this is a general problem for many starting
                                >large format film-makers even for flat screens. (Who really wants to see
                                >the zit on the actors cheek on a 5 story high face???)

                                Who has been shooting 15/70 films in recent years?

                                About 30 years ago I traveled to San Deigo to see the initial offerings
                                of the Reuben H. Fleet Space Theater 'Journey to the planets' and 'Garden
                                Isle'. The former was the cover story of a Cinema related magazine,
                                containing images of the giant globes and models produced for this Solar
                                System travelogue. On a dome it was amazing, particularly an excellent
                                model shot of Saturn, a task deemed too daunting for the producers of
                                '2001'. The Hawaii travelogue, 'Garden Isle' was shot entirely in fisheye
                                format and was stunning, one felt you could toss a pebble into infinity
                                during bthe helicopter shots.

                                Since that time there seems to have been so few films created entirely in
                                Omnimax that the medium esentially 'died on the vine'. Nobody seemed to
                                take the Imax dome projection format seriously enough to market the unique
                                capability of capturing immersive enviornments and reproducing them to
                                viewers near the center of the dome. The lack of films shot exclusively in
                                15/70 fulldome format tended to negate the reason for having a dome at at
                                all to show IMAX material.

                                Token wide angle sequences would be added to IMAX productions so as not to
                                entirely ignore domes, but full hemispheric film migrated to a modest
                                representation in smaller formats. The sheer cost of the medium was a
                                decisive factor, and flat screen presentation is admittedly a better way to
                                show off the sheer resolution of large format film on more conventional
                                rectangular giant screens. Omnimax ended up more of a 'worlds fair'
                                presentation medium than anything someone could hope to create original
                                material with for ones facility.

                                Looking around for web references, among the sparse references to 'cine
                                360' I came upon this reminder of a 'lost gem' of fisheye 35mm awaiting
                                scanning into digital media, 'Space Shuttle, An American Adventure':

                                "The camera, called a Cinema-360, is a modified Arriflex 35mm Type III fitted
                                with a Nikon f/2.8 lens that provides a 180 x 360 degree field of view. The
                                format of the film, a joint project of NASA and Cinema-360, Inc., a nonprofit
                                organization that develops educational films for planetariums, is designed
                                for use in planetarium domes. The footage will be used to produce a
                                documentary called 'An American Adventure.'"

                                What has become of this?

                                As for issues like closeups, the esthetics of Fulldome cinema will be
                                tried and refined as the medium attracts more 'Directors'. The methods of
                                defining the frame and composition will evolve from those of film, but the
                                storytelling methods will accomodate the advantages of as well as work
                                around the disadvantages of having a 180 degree view. The tilt, 22.5
                                degrees optimum, provides for the unified audience similar to conventional
                                cinema, and gives at least a broad 'frame' from which things can come and
                                go.

                                In directing a presentation with people appearing I would never use
                                closeups, in fact I would generally go out of my way to keep the entire
                                figure in view. Camera moves are costly to arrange, requiring tracks and an
                                associated infrastructure. For this reason I expect most earlier
                                productions involving actors to use static cameras. A 'Motion Control'
                                camera rig can record the moves and the data can be transferred to a
                                'virtual set' in an animation software, allowing blending of real and CGI
                                enviornments. This ventures well into the costly and difficult realms of
                                visual effects production, which I have experience in.

                                The maturity of Fulldome video will arrive when affordable cameras exist
                                capable of scanning 4K fisheye files 30 frames per second. Now only film
                                cameras can approach this, and at forbidding cost. One interesting
                                transitional method to recording moving enviornments can be seen here:

                                http://www.glassworks.co.uk/search_archive/jobs/vw_dome/

                                Already HDTV camcorders are available, if one isn't too picky about
                                resolution and foreground parallax issues two such cameras might be used to
                                capture a circular format and blended together with suitable processing
                                software. Perhaps more can be used to build up a suitable detailed image as
                                such cameras get smaller with time. My concern down the road is that the
                                dedicated cameras of the future suitable for Fulldome video capture might
                                end up being massively expensive things that become as inaccesable for
                                experimenters as became the case for Omnimax.


                                Don Davis
                              • Ryan Wyatt
                                ... Check out http://www.micoy.com/immersive_video/ They use 84 cameras to capture 360-degree stereo. We ve seen a few samples here in New York that show some
                                Message 15 of 17 , Aug 7, 2004
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                                  Don Davis wrote, referring to real-time capture of fulldome frames:

                                  > Perhaps more [cameras] can be used to build up a suitable detailed
                                  > image as such cameras get smaller with time.

                                  Check out
                                  http://www.micoy.com/immersive_video/

                                  They use 84 cameras to capture 360-degree stereo. We've seen a few
                                  samples here in New York that show some promise.

                                  Earlier, though, Don had also written:

                                  > The methods of defining the frame and composition will evolve from
                                  > those of film,...

                                  I hope not. Many of the hard cuts and other butchery I've seen in
                                  fulldome presentations are lessons from the film vernacular that I hope
                                  we learn to avoid.

                                  > but the storytelling methods will accomodate the advantages of as well
                                  > as work around the disadvantages of having a 180 degree view.

                                  My latest schtick has been that what we're talking about with fulldome
                                  is not so much "storytelling" as what I like to call a "narrative
                                  journey." Fulldome is about place, about the viewer's relationship to
                                  an environment, and framed stories don't provide an adequate analogue
                                  to the experience at which fulldome excels. It's no coincidence that
                                  most IMAX films are travelogues: a) the format lends itself to the
                                  topic, b) travel works with the historical purpose of museums as places
                                  to travel without leaving home, and c) travelogues are relatively
                                  straightforward to produce. I prefer to emphasize a), and I think the
                                  very deliberate construction of the Rose Center's two space shows
                                  speaks to that as well.

                                  Just a few late-night thoughts... I'll happily elaborate later.


                                  Ryan, a.k.a.
                                  Ryan Wyatt, Science Visualizer
                                  Rose Center for Earth & Space
                                  American Museum of Natural History
                                  79th Street & Central Park West
                                  New York, New York 10024
                                  212.313.7903 vox
                                  212.313.7868 fax
                                • Don Davis
                                  ... Any technique which can be used in film can also be misued or done carelessly. I m not sure a hard cut is necessarily an evil, just one method of getting
                                  Message 16 of 17 , Aug 7, 2004
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                                    Ryan Wyatt writes:

                                    >> The methods of defining the frame and composition will evolve from
                                    >> those of film,...

                                    >I hope not. Many of the hard cuts and other butchery I've seen in
                                    >fulldome presentations are lessons from the film vernacular that I hope
                                    >we learn to avoid.

                                    Any technique which can be used in film can also be misued or done
                                    carelessly. I'm not sure a hard cut is necessarily an evil, just one method
                                    of getting from one point of a film to another which is more appropriate in
                                    some circumstances than others. The long history of film has many examples
                                    to draw from other than the recent styles of poor writing, rapid cuts and
                                    theme park like gyrations. I think more in terms of Kubrick and his sense
                                    of grandeur. The 30 year old 'American Cinematographer' magazine article on
                                    Omnimax I mentioned earlier already recognized the longer time it takes for
                                    an audience to absorb a hemispheric envionment, requiring longer scenes
                                    than a similar story might use done in conventional cinema. Other
                                    refinments in film grammer will emerge as Fulldome 'films' develop.

                                    >> but the storytelling methods will accomodate the advantages of as well
                                    >> as work around the disadvantages of having a 180 degree view.

                                    >My latest schtick has been that what we're talking about with fulldome
                                    >is not so much "storytelling" as what I like to call a "narrative
                                    >journey." Fulldome is about place, about the viewer's relationship to
                                    >an environment, and framed stories don't provide an adequate analogue
                                    >to the experience at which fulldome excels.

                                    People should be encouraged to strike out in different directions with the
                                    unprecedented creative tools now open to them. As Fulldome content
                                    proliferates there will be examples of straightforward education, of
                                    storytelling, and of difficult to pidgenhole audio-visual enviornments. I
                                    think, for instance, a science fiction story done in Fulldome could be an
                                    amazing thing! I can also imagine creating an enviornment something like
                                    the 'chill room' of a rave, something to take up where the laser shows left
                                    off.

                                    >It's no coincidence that most IMAX films are travelogues: a) the format
                                    >lends itself to the topic, b) travel works with the historical purpose of
                                    >museums as places to travel without leaving home, and c) travelogues
                                    >are relatively straightforward to produce.

                                    And travelogues are 'safe' topics to produce films about, the medium
                                    being too expensive to take chances with. May that not be the fate of this
                                    new media.


                                    Don Davis
                                  • david mcconville
                                    Micoy came to Minneapolis last year and did a test shoot for the elumenati with their massive spherical stereo camera. In the interest of encouraging forum
                                    Message 17 of 17 , Aug 8, 2004
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                                      Micoy came to Minneapolis last year and did a test shoot for the elumenati
                                      with their massive spherical stereo camera. In the interest of encouraging
                                      forum usage so we can collectively document our fulldome live capture
                                      knowledge, I've posted a description of it to
                                      http://fulldome.org/index.php?option=com_simpleboard&Itemid=28&func=view&id=14&catid=10
                                      (you'll have to create an account if you don't have one).

                                      I've included a lot of information about other live capture systems as well
                                      (including HD, film, other spherical cameras, CameraLink, etc) that could
                                      eventually turn into a fulldome live capture guide that can help newcomers
                                      understand the issues and technologies surrounding filming for the dome. I
                                      like where you're going with the "Narrative Journey" concept. I'd love to
                                      see a live capture guide incorporating the aesthetic and production
                                      philosophy (expanding on Ben Shedd's "Exploding the Frame") as well as keep
                                      everyone up-to-date on what cameras and lenses are available.

                                      david


                                      --------------------------
                                      david mcconville
                                      http://www.elumenati.com

                                      p: 828.236.9777
                                      f: 828.236.9779
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