In the Kitchen Workstation – Part II post I did a 3d rendering of the proposed addition to our kitchen cabinets. Renderings attempt to accurately represent reality using 3d shapes along with varying textures and lighting. In order to better explain what it takes to make one of those models and why it can be so incredibily time consuming I will spend some time going into a little more detail.
First of all, the base of every 3d drawing is a polygon, thousands and thousands of polygons. Each object in the model is made up of a varying number of polygons which, put together determine the object’s shape. For instance, a simple cube would be made up of (6) polygons, one for each side. The problem is that polygons can only truly represent a flat surface. This means curved objects have to be made up of a bunch of very small polygons. The more polygons the more you can trick the human eye into believing that, for instance, a ball is round instead of faceted. An accurate 3d model is essential to producing realistic renderings. No matter how good your materials or lighting, if your model is shoddy the rendering will be shoddy. I used Chief Architect to produce my model. It is designed specifically for residential drafting and comes with a variety of built in items such as light fixtures, appliances, cabinets, etc. Believe me, I did not create all of the 3d objects in my rendering from scratch. That would have taken days or even weeks of work.
If you were to simply draw lines around the polygons of an object you would essentially get a wireframe model. To provide more realism, each polygon is assigned a material which will determine its characteristics apart from its shape. In Chief Architect every material has (6) adjustments (ambience, diffuseness, specularness, shininess, emissiveness, transparency) which determine the way it reflects light. With these adjustments you can differentiate between something made of clear glass, shiny chrome, or black fabric even if they all had the exact same shape. A material could be a simple color or a patern as with wallpaper. However, plain colors are not very represenative of reality since nearly everything in the world has some sort of texture or pattern.
In addition to the material possibilities, light is the next extremely important factor. In Chief Architect every light source can be adjusted for type (point, spot parallel), color, height, tilt, direction, cutoff angle, and drop off rate. The light’s interaction with the objects is modeled using a technique called raytracing. This technique actually traces the rays (believe it or not) of light as they reflect off different surfaces to produce the final image. Chief uses the free software POV-Ray to do raytracing on its models. This method can create very realistic reflections and shadows.
When you combine all of these variables for each object (material types and lighting) in the scene along with the fact each rendering can take hours (my final render took for the kitchen scene took around 24 hours but smaller preview renders can be done much quicker) and you can see how it can be very time consuming. The main reason 3d modeling can be so complicated is because reality is so complicated. Just think, for instance, of the amazing detail of structure, texture, and color of an ordinary leaf and what it would take to accurately represent that in 3d graphics.
To see some of the absolutely amazing things that can be done with these redering techniques check out the Hall of Fame on the Pov-Ray website. Many of the renderings there approach photo realism.
