Modeling for Animation | 2 | WebReference

Modeling for Animation | 2

Modeling for Animation

“When building a model, name everything left to right. As an example, everything on the right side could be named R: R_wrist, R_shoulder, R_leg, etc. Another tip is to color each side independently so that you can visually see the difference.”

“When setting pivot points, one of the most important considerations is that the local rotation axis of each joint is oriented properly relative to the other joint in the hierarchy. For example: With a hand you would have to think about the origination of the joint so that when you animate the hand – all the fingers are moving in the right direction relative to the wrist and the hand.”

On the issue of texturing, Williamson said: “If you’re working in Polygons, you want to make sure that you have good UVs. If you’re working in NURBS, you want to make sure that your surface parameterization is uniform.”

“How much detail you place in your texture depends on a number of different variables, one of which would be determining how close the model is going to come to the camera. The detail, or quality, of a textured model is a result of both the geometry quality (how it was modeled) and the texture size itself. Finding the right combination for your purpose is key.”

About Detail, Etc.

To elaborate, detail determines whether models are built quickly or if they will take a considerable amount of time. The more detail a model has, the more complex it becomes and the longer it takes to build. But this also creates other issues, such as textures, painting on the model and rendering.

A good place to start with models that have a low level of geometry detail, with as few points as possible. A good starting point is to work with primitives. It’s easier to create a base shape when there are fewer points to manipulate. If you need to add points, do so, but don’t make the shape more complicated than necessary.

An example is a globe which would use a sphere primitive. How many segments are used is dependent on how close the globe is to the viewer. If the globe is close up, you would want more geometry to create a smoother surface, but if it’s in the distance, you can get by with less.

In this screenshot (from Maya 5), you see two spheres in the perspective view. The sphere in the foreground has a Radius of 8 and 25 Subdivisions around the Axis and Height. The sphere in the background has a Radius of 1.5 and 10 Subdivisions around the Axis and Height. Compare the apparent level of smoothness between the two spheres.

In 3D, there are many instances where a model will benefit from textures In the screenshot below, what makes this shape appear realistic is the combination of textures; how they are placed on the sphere, the level of transparency between them and whether a bump map is used or not.

This example (in 3DS Max) uses a combination of textures made up of satellite photography of the Earth in combination with levels of transparency and self-illumination.

Created: June 5, 2003
Revised: October 10, 2003