| An instance is an interdependent copy of a 3D | | | | doors, windows, and columns of all the buildings. |
| Application's object; when you make a change to | | | | When you upload texture maps, remember that |
| any of the instances, all the other copies change | | | | the UNIX system your Web server is most likely |
| also. Instances are useful in creating smaller-size | | | | running is case sensitive and will not find the map |
| files for the Web; when you use an instance, the | | | | files unless the case is exact. |
| set of faces that make up the instance object | | | | If you specified a map called bridge.gif in the |
| has to be defined only once in the virtual reality | | | | Material editor, for example, but the file you |
| code. | | | | upload to the Web server is called Bridge.gif, the |
| Consequently, you can use the same piece of | | | | map will not display. Texture maps look strange, |
| geometry many times without any increase in the | | | | but not unattractive, when you zoom in close |
| download time for the file. Texture Mapping | | | | enough to see the pattern of the colored pixels. |
| Versus Geometry: By applying different texture | | | | This is becoming part of the "style" of virtual |
| maps to the boxes, however, and changing the | | | | reality models, as you will see if you look at some |
| scale and orientation of the buildings, you make | | | | of the Web sites listed later in this chapter. One |
| the scene look much more varied than it really is. | | | | way to work with this limitation rather than |
| Although texture maps increase the download | | | | against it is to design texture maps that make no |
| time as well as the speed of screen redraws, the | | | | attempt to look realistic, but look as though they |
| extra time incurred is a small price to pay | | | | were painted on, like stage scenery. |
| compared to what it would cost to model the | | | | |