Re: Pano2VR makes different default cubefaces
- Hi Thomas,
But, if the default value is width/4 you are using this figure:
http://www.devalvr.com/fiero/equicube2.jpg , loosing a lot of
information in the conversion.
If you take the output equirect from PTGui, all values superior to
3.14 in the divisor are loosing information in the conversion.
--- In PanoToolsNG@yahoogroups.com, Thomas Rauscher <yahoo@...> wrote:
> fierodeval wrote, On 01.11.2008 21:59 Uhr:
> > Yes, I understand. But when you speak about the "sqrt(2)", you are
> > speaking about the figure in the right of this image
> > http://www.devalvr.com/fiero/equicube.jpg . Te correct figure is in
> > the left and this figure is valid in the two directions.
> > Then, if I understand correctly, you say that the figure for
> > equirect->cube conversion is the left image and for cube->equirect is
> > the right image?
> Yes. correct. Because the cube faces *could* contain more
> the corners.
> If the source was a equirectangular with 1/Pi as factor for the cube
> faces size then it is safe to just use the left type of conversion
> because the pixels in corners are stretched by a factor of sqrt(2).
> If the source images are cube faces, for example of a rendering from a
> 3D software, then you need to use the conversion on the right side to
> avoid losing resolution/information.
> The factor Pi*sqrt(2) would also be true if the equi->cube was executed
> with a factor smaller then 1/Pi*sqrt(2) to get the maximum out of the
> cube faces. Another case would be if you recover a equirectangular
> a QTVR where you don't know the original resolution.