Review of a new computer tool
- For those interested in urban design tools, a review of CityCAD
software at Planetizen:
Visualizing and Analyzing Plans with CityCAD
30 July 2009 - 9:00am
• Charles A. Donley, AICP
Planning technology expert Charles A. Donley reviews a new piece of
software that combines the worlds of Computer-Aided Design and
Geographic Information Systems to help site planners visualize and
analyze their plans.
CityCAD is a conceptualization tool for urban design. The standalone
software integrates simple drawing tools with impact analysis. CityCAD
combines elements of Geographic Information Systems and Computer-Aided
Design, targeting the interests of site planners without a lot of
extraneous features and functions.
CityCAD offers a tool for exploring urban design concepts and
evaluating the impact of a plan. You can design streets, massing, and
density while concurrently calculating floor areas, costs, emissions
and other factors.
The main display of CityCAD.
The CAD acronym in the product name acknowledges the software
developer’s orientation: they wanted a simple design tool. But they
also wanted a smart tool to measure the impacts of a project: this is
GIS. The software is a hybrid of GIS and CAD, wisely adapted to urban
design, yet there is little acknowledgement of the GIS relationship.
But the software approaches the CAD-GIS hybrid in a user-friendly way.
Users sketch in streets to define blocks, assign land uses and
densities, and then identify potential impacts in real time. CityCAD
automatically generates a plan based on user defined design standards.
A simple street centerline generates pavement, sidewalks, setbacks and
trees from a selected cross section. Relocating the centerline
recalculates the block area, dwelling units, non-residential space,
and the associated impacts. Resetting density, unit dimensions or
total units recalculates the other parameters.
Project drawing is done in a simple 3D perspective view, an important
feature for those unskilled in translating a flat map into the real
world. The resulting image is cartoonish, not photo real. Creating
more complex geometry requires imports from other software such as
AutoCAD or SketchUp.
CityCAD can import AutoCAD files, but the typical complexity of CAD
drawings limits their usefulness in this decidedly less sophisticated
software. If you have a CAD drawing that you’d like to use, it may
make more sense to import only a few basic elements. For example,
maybe you just import the street centerlines, eliminating most of the
lines, points and labels. Alternatively, you could import a site plan
as an image and digitize in the streets. The drawing process in
CityCAD is quick and intuitive.
Better yet, use CityCAD’s tools for conceptualizing the plan from
scratch. A range of standard graphic elements can identify edges,
landmarks, nodes, and linkages. You can then draw the streets by type,
thereby defining the blocks and review the resulting impacts. CityCAD
also allows you to refine the design standards and layout to achieve
the desired results. Ideally the design process could begin with a
georeferenced aerial photo to illustrate existing conditions.
The software has a British orientation as evidenced by the urban
design features, default unit of measures and the accents in the
tutorial (not that that is bad). You can adapt the software to many US
standards -- and most urban design principles are universal. But my
initial results still have a UK feel to them.
For example, I would like to see an automated method for depicting
detached buildings with sloped roofs, such as single family units or
townhomes. Breaking up a building around the entire perimeter of a
block involves importing CAD drawings or manually editing individual
structures. Adding inputs to the detached block category could include
building separation, number of units per building and maybe roof
slope. This will greatly expand the software’s usefulness in the U.S.
Below are some of the analysis tools that would be of most use to
• Impact analysis topics include energy consumption, water demand,
trash generation, parking spaces, and CO2 emissions. The quality of
life topics expand with a couple clicks.
• Appraisal tools identify project costs and revenues. Adding the
phasing function can produce a great, draft project pro forma.
Developers can quickly explore the cost and revenue of multiple
scenarios. The Triggers highlight infrastructure concurrency issues.
• Livability measures residential proximity to community facilities
(e.g. bus stops or schools). The analysis uses straight-line distance,
which can be misleading in areas with poor pedestrian circulation.
Future versions should consider measuring the routed distance (e,g,
following sidewalks). I understand this is a very complex feature, but
straight line just does not represent reality.
• Activity is a cool analysis tool that depicts daily patterns of
land use activity. The problem with Activity tool is you must assign
the hours of operation for each activity, a time consuming effort, but
perhaps there is a work around. The Holistic City website includes 10
project downloads including Central Park in New York. Marketing to the
US market could benefit from another US project with the multipliers
and factors adjusted to US standards. This includes land uses
completed with activity settings; dollars, acres, and gallons as units
of measure; and typical appraisal values. New users could explore the
software results and start editing the values. Then they could delete
the layout and start their own design with the US standards already in
The new version also adds a route and tree manager. Creating a
customized street cross section from a simple centerline is powerful.
But I wonder how you deal with turn lanes.
Rather than list all the functions and techniques, I encourage you to
watch the video tutorials at http://www.holisticcity.co.uk/citycad/onlinehelp/
. In an hour you will gain a good feel for the components and basic
operation. An 8 hour trial version is also available. Then release
your creative energies to decide how CityCAD can benefit your
CityCAD targets neighborhood-level design. Current computer processors
would struggle with an entire city. The drawing tools lack the
complexity to explore architectural details. You can try to do more,
but the sweet spot is probably 4 to 40 blocks.
The usability is good. It took me a couple hours to make sense of the
software, but I may be more modeling- and technology-oriented than
most planners. The button count at start-up is on the high side and
some buttons are unnecessary for first time users. There is no Apple
The Help suggests the user can customize the model with AutoCAD
imports and XML code, but I refuse to accept the challenge. As a
planner, I want technology to work right out the box.
Relatively young software (first release, June 2008) typically
contains many bugs. I found only one bug (start errors with Vista
operating system are addressed in Help). The software is not built as
an extension of other software (AutoCAD or ArcGIS), so it is not
subject to changes in the parent software. My experimentation with
CityCAD was limited and simplistic, but Holistic City seems to have
stable product. Regardless, be forewarned that your creative
application of CityCAD may find new issues.
For planners looking to integrate GIS-based analysis into their
existing CAD drawings, CityCAD offers a fairly straightforward option.
It allows users to easily explore urban design concepts and understand
how plans will play out once in place – two critical activities that
have been compartmentalized too long.
Charles A. Donley, AICP is an urban planner who specializes in
applying technology to planning issues. Chuck is president of Donley &
Associates, where he has worked on projects nationally and
internationally. Chuck brings 25 years of experience in public and
private sector planning, working on current and long range processes.
As Technical Director for CommunityViz, he guided training,
professional services, technical support, and software development.
Chuck is also the instructor of a variety of instructional Planetizen
webinars, teaching planners such technologies as Google Earth,
SketchUp, CommunityViz, and GIS concepts. Learn more athttp://www.planetizen.com/courses
Montreal QC Canada