CAP 202 - Computer Animation II

Lesson 15 - Using Maps

Objectives:

This lesson discusses maps and textures. Objectives important to this lesson:

1. Definition of a texture
2. Differences between materials and textures
3. Map channels
4. Building a material from a map
5. Creating realistic textures
6. Differences between 2D and 3D maps

Concepts:

In the last lesson, you made a couple of simple materials that were smooth. In this lesson you consider textures, which are defined two ways:

• the physical composition, appearance, and feel of a surface
• the end result of a material

Maps are what we add to a material in 3DS Max to give the material a specific appearance and feel. The text classifies maps in two categories and several types. The two categories are bitmaps and procedural maps. Essentially, bitmaps are any kind of raster image while procedural maps are vector images that can be scaled without losing detail.

The text uses two phrases interchangeably. Map types and map channels are the same thing. A list of common types appear on page 435.

• diffuse color - the surface color of an object
• specular color - the color of reflections (highlights) on an object
• specular level - the intensity of reflections (highlights) on an object
• glossiness - the size of the reflective area (highlight) on an object
• opacity - a spectrum that runs from opaque to transparent; we can see through transparent objects, we cannot see through opaque objects
• bump - makes the surface of an object uneven, bumpy
• reflection - controls how reflective an object is on all surfaces.

Exercise Notes and Questions

Work through the exercises and turn in your answers to all questions below as part of the homework for this assignment.

Exercise 1: This exercise worked sometimes on my computer, but mostly not. The discussion tells us the we can turn visibility for maps on and off. The results may vary depending on the graphic capacity of your video card and your RAM usage at a given time.
Question 1: In step 8 what are you told to click?
Question 2: In step 10, you are browsing for a "bitmap". What are three file types that 3DS Max would recognize as bitmaps, in the context of this exercise?
Question 3: In step 12, you are told to select Show Map in Viewport. Does it work on your screen?

The text pauses between exercises to discuss showing maps in viewports. We are told that we can turn this on and off for each map, and that we can turn in on globally (for all maps in a scene).
Question 4: Where is the option to Activate or Deactivate All Maps?

In the course of the discussion, the text tells us we can combine several different maps to make a composite, which is more likely to resemble some real materials. It also tells us that we can use a 2D or 3D map on an object. A difference between them is that a procedural 3D map may penetrate the object, mapping all the way through it, while a 2D bitmap only covers the surface of the object. This penetration could be useful for an object like a rock that is meant to break apart in the scene. It would not be an advantage for the oil drum in the last scene: the outside of the drum is not meant to look like the inside.

Exercise 2: Exercise 2 has more steps than any exercise so far in the text. It is good that this is the last exercise in this lesson. Make some notes as you perform these steps or you are likely to forget the features they walk through.
Question 5: The term "fractal" is used several times. Google it. What is a fractal in the sense used here?
Question 6: The text forgets to tell you to make the map you are customizing visible in the viewport. Where is the button to make this happen? What does it look like?
Question 7: How does the text have you copy one map channel to another?