3D Animation Workshop: Lesson 55: More Texture Mapping | 2 | WebReference

3D Animation Workshop: Lesson 55: More Texture Mapping | 2


Lesson 55 - More Texture Mapping - Part 3

The yellow and blue squares are all exactly the right size on each wall, but this closeup shot of the corner reveals that the two maps don't meet correctly. It's possible to shift one of the maps over a little so that it looks are if the pattern is wrapping through the corner, but this adjustment distorts other corners. If our camera won't catch the other corners, this may not matter. But let's keep trying.

At the end of the previous lesson, we looked at the possibility on using the inherent or implicit mapping coordinates of the geometry for mapping purposes, so that the texture follows the surface without need for projections. NURBS surfaces necessarily have u and v surface coordinates in their structure, so let's try building the room, or at least the walls, using NURBS.

We'll start with a NURBS curve. NURBS curves are usually known for their organic smoothness, but they can turn hard corners as well. You just need to put multiple points where you want sharpness.

By extruding the curve upward, we create the walls. The normals are facing inward, but we could have flipped them had they been facing out.

Now we put the map directly to the uv coordinate system inherent in the surface. And although the scale is wrong, the pattern maps evenly on the walls and through the corners.

By scaling the map down horizontally, and using tiling, we get the correct pattern of blue and yellow squares.

This approach is especially nice because we can shift the whole map around the wall as a unit if we need to, and it crawls around like a snake eating its own tail.

MAX is unique in that many kinds of non-NURBS surfaces can generate their own mapping coordinates. We could have built these walls by extruding a rectangular non-NURBS spline, just as we extruded a NURBS rectangle, and the result would have been the same. I used NURBS in this example because this mapping technique is directly applicable to all applications that implement NURBS.

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Created: Dec. 8, 1998
Revised: Dec. 8, 1998

URL: http://webreference.com/3d/lesson55/part3.html