CAP 202 - Computer Animation II

Lesson 6 - Chapter 9


This lesson continues the discussion of terrain elements. Objectives important to this lesson:

  1. Trees
  2. Plants
  3. Rocks
  4. Sky
  5. Clouds
  6. Water

The author begins with a short discussion about deciding between making organic objects that are faithful to nature, or making organic objects that look good or good enough. His pragmatic decision is to make objects that look nice, since this is a game, but to make some decision as well about a minimum amount of realism that his objects must maintain. He does not produce a hard rule to apply. His decision stands as an example to us to make our own decision about realism in our production.

As his example for the chapter, the author seems to be thinking mainly about a jungle setting. He describes making a general texture for this setting before discussing specifics for the object types listed above. In the course of the chapter, the author recommends several software tools for specific tasks. The DVD that comes with the text has installable copies of the software he discusses. We will not be using these programs in the classroom, but you may wish to try them out on your own computer to experiment with his suggestions.

Trees - the author's preference is to start with a bark texture, then create a mesh for a tree, then unwrap the mesh, and create a skin for the unwrapped tree. It would seem like a wasted step to make the bark texture first, but it is more of a planning step, creating a resource that will be used in the skin creation. Note the steps the author describes on page 226, using filters and modifiers to get his desired effect.

The author lists three art programs (in addition to Photoshop) that he recommends for texturing trees:

  • Deep Paint 2.0 - recommended for the brushes, illustrated on page 231. It is a free program. I found several references to it on the Internet, most of them a few years old.
  • TreeMagik G3 - recommended for creating a small number of trees, as illustrated on pages 232 and 233. This one is not free, despite the claims on the crack sites you will find on the Internet, but not high priced, either.
  • SpeedTree - Not free, and not clear how much it costs, but it is recommended by the author for creating forests. It makes very pretty output.

Plants - The chapter moves on to discuss creating other sorts of plants for your terrain. The author makes a good point that in a forest or jungle, you might have only a few species of trees in a given location, but you might expect to see many varieties of grass, weeds, flowers, vines, ferns, mushrooms, and more. He makes one software recommendation for plants: Plant Life. (Plant Life and TreeMagik are marketed by the same company.) The author recommends using Plant Life to create models for the plants, and then creating your own textures to apply to them. Some screen shots from the program are on pages 242 and 243.

Rocks - Again, the discussion of rocks is centered on the jungle scene in the author's mind, but we can take some general advice from it.

If we were making the terrain for another kind of setting, what would the rocks be like? Smooth or rough edges? To answer that, think about the geologic process that formed them, and about the weather they would have been exposed to. (For the discussion of rocks in general, we can ignore rocks that have been worked by humans or other characters, which are more properly considered props and artifacts.) Would the rocks be large or small? Plentiful or rare? Which class do the rocks belong to: igneous, sedimentary, or metamorphic? If you can't answer these questions, you should be thinking about some basic research into rock formation, and images of appropriate examples.

The author presents a process for making a rock model on page 241 that you can follow in 3DS Max. His images of his rock are on page 244. The texture he used was based on a photo, which he modified in a photo editor. You should try to do the same thing, after you find some appropriate rocks to photograph. (No, you can't just grab a photo from the Internet.)

Sky simulation - Adding a sky to a game will be necessary for any outdoor scenes. The author discusses three approaches to putting a sky into the game.

  • sky image - A single image, as seen in older games, that is not very dynamic or convincing
  • sky dome - A dome or cube that covers the game environment is given a sky texture. More convincing, since the texture can appear to change as the character moves under it. The author does not care for this technique because the dome itself is an object that the characters must avoid and it gets in his way when working on the game.
  • sky box - This one is trickier. A sky box is a separate room with a camera in it that is slaved to the player/character's movements. A dome in the sky box has a texture on it for the sky. When the character moves, the camera swivels: it points to a part of the sky that the character would see. The player sees a composite on the screen of what the character sees in the game world, on top of what the sky box camera sees in the sky box. See examples on page 248.

Clouds - The text returns to a tutorial format to show you a method for creating clouds. It begins on page 250.

Water - The author discusses several kind of effects that may be combined to simulate water in a game. He does not provide a tutorial for creating a water feature.

Exercise: Cloud tutorial

You can carry out this tutorial in the classroom, but some of the instructions and screen shots will not match our version of Photoshop.

  1. Perform each of the steps in the lesson, and make notes about each step. Specify what was the same, and what was different in our version of Photoshop.
  2. Compare your final version of the cloud image to the one that came on the DVD.
  3. Turn in your notes as homework for this assignment.

Exercise: 3DS sky dome

  1. Open 3DS Max. Open one of the outdoor scenes you have created.
  2. Add a sky dome to the scene, and texture it with an appropriate material.
  3. Show me the scene with the sky dome for grading.

Exercise: Unreal sky dome

  1. Watch the tutorial behind this link about using UE to add a sky dome.
  2. Follow the procedure from the tutorial to add a sky dome to an Unreal level.

Exercise: Finishing the Term Project

  1. Complete all the required elements of your city scene, including the sky dome element discussed above.
  2. Create at least three renders of your scene that show off the elements you have created: streets and intersections, parking structure, trees, textures added, props added to the scene, buildings, sky dome, and any other elements you have included. All renders must include camera movement through the scene.
  3. Composite those renders into a movie in After Effects. Give me a copy of the movie, which will be shown to Dean Fulcher and Dr. Sala as examples of work done this term. Retain copies of the renders and the final project movie for use in your portfolio.