3D Modeling and Landscape Architecture

3D computer modeling provides the landscape architect with another media with which to explore ideas and communicate with the client. It can do some things that we have trouble doing with conventional media, such as using animation to view motion, light/shadow and time changes of a site. I have used 3D modeling/rendering/animation packages to do drive-throughs/walk-throughs/cycle-throughs, grow plant masses in both forest and urban sites, explore shadows and night lighting and envision soil moisture changes in agricultural fields following a rainstorm to name a few.

Models typically take from 10 to 40 hours+ to develop, depending upon complexity, photo-realism and animation effects. These are, of course, very rough guesses based on my experience in modeling -- less than about 10 hours is not enough time to develop a good model, and you can spend as much time on a model as you have energy and budget. I have been satisfied with what can be achieved in 20 to 30 hours. Most of the images on these pages were taken from models created in that timeframe.

I've used Strata StudioPro to develop all of my models, although there are many modelers available in a range of capabilities and prices. Here are a few examples for the Macintosh, which I use because of its well-integrated cross-program abilities (the following opinions are my own. I haven't used any of these products and am mostly repeating what other users have said. I strongly encourage you to check out these products yourself. Most have web pages.)

At the low end are RayDream Designer and KPT Bryce. They cost a couple of hundred dollars each. I've heard that they are pretty good modelers, although both create images that are identifiable as being generated by RayDream or Bryce. Last I heard, neither did animation, but Bryce's next version will have that capability -- it may be out by now. Bryce excels at outdoor landscape imagery. RayDream is focused more on still-lifes. Low to mid priced are Strata Vision3D and Infini-D. Vision3D is a scaled down version of StudioPro, including many of StudioPro's abilities. Vision3D and Infini-D are in the $500 price range. Strata StudioPro is mid to high-priced at around $900. It has good modeling,rendering and animation abilities, but lacks features such as inverse kinematics (used for jointing of limbs), particle animation (which can mimic the flow of fluids and gases such as water and smoke), and surface detection (to allow objects to "rest on" or "bounce off" one another). At the high end is Electric Image in the multi-thousands of dollars.

In addition to modeling, rendering and animation software, I've used Adobe Photoshop and Premier to edit stills and assemble animations and stills into video footage for output to tape. Interactive multimedia packages such as Allegiant Supercard or Digital Chisel can be powerful tools in public involvement programs.

Several special problems exist for the landscape architect doing 3D modeling. Two of the most significant are terrain and tree modeling. Representing complex terrain can tax a system fairly heavily. Please see Paul Bourke's dissertations on this subject. He provides an excellent description of terrain modeling techniques and also of modeling trees using l-systems. He is associated with the University of Auckland.

Modeling of trees can be a complex task. This is because to model every leaf on a tree takes hundreds of thousands of polygons, which will task any desktop computer system. The modeling of every leaf on a site with plant masses that may be composed of tens to hundreds of trees, shrubs and groundcovers becomes unfeasible for most systems. Some level of abstraction is necessary, by creating masses which represent either groups of leaves or whole trees. In modeling large scale spaces with natural vegetation the latter method is preferable, though I have used the former on a forest scene composed of 121 trees (an 11x11 grid).

Below are several methods I've tried with satisfactory results:

1) Canopy Abstraction: Model the trunk and several main branches. Create two circular surfaces in plan view over the tree. Distort the surfaces vertically to make them look like irregular half spheres -- the more wavy the better. Make one tall and thin, the other wide and short. Position these surfaces so that they intersect in a roughly canopy shape. Create a pattern that looks like a circular grouping of leaves of approximately the texture you want. Make all but the leaves transparent. Apply that to each of the surfaces from above, tiling in a grid-pattern 3 or 4 times across the surface. The tiling of textures with transparent edges creates clumps of vegetation. The two intersecting surfaces hides the grid-pattern and creates "see-through" complexity as well as realistic shadows. This technique was used in both the forest stand model and the urban plaza.

2) Planar Modeling: Create a rectangular vertical surface. Draw a tree profile (or scan a photograph and remove all but the tree). Apply that to the rectangle along with a transparency map for all but the tree. Duplicate this rectangle and rotate several times to make a star pattern when viewed in plan. This method is quick and easy and makes realistic trees when viewed from a distance. It is also takes little memory and is quick to raytrace, however the illusion of three-dimensionality breaks down up-close.

3) Vegetation Clump modeling: Create the trunk and branches to the level of detail you want to show. Make a pattern that is a grouping of leaves, maybe 3 or 4 (or more). Apply this to a circular surface, which may be distorted into a 3D object. Add as many of these surfaces as needed to create the desired canopy density, shape and texture. Change scale and rotation for each instance. This method is somewhere between #1 and the modeling of individual leaves in both realism, total polygons and rendering requirements.

4) There's probably many more ways. Let me know if you've tried something that you like.

I've delved deeper into the specifics of modeling than I'd planned on this page. I'd like to hear about your experiences with 3D modeling or image processing and landscape design or planning. Drop me an email, and we can discuss techniques.

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Please email me at etarm@darkwing.uoregon.edu with comments or questions.

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