Thread: This process of applying the image

This process of applying the image to the object - and there are many variations possi¬ble - is called mapping, and it is worth spend¬ing time to study all the methods and try each of them out when learning modelling. This process of applying textures and other maps is one of the key techniques in creating realistic models. Patience and attention to detail are vital, and will be well rewarded.

The grain in a piece of wood as just described is simply a texture map, but there are many other types of map that can be used. For example, the surface of a piece of gold will reflect objects behind the camera (the viewpoint from which the image is rendered). These reflections can be created by tech¬niques such as ray-tracing - described later ¬or by the use of a reflection map. The soft¬ware will added the reflected image to the main texture of the material from the reflec¬tion map.

There are many other types of map used, and the latest version of MAX provides for a total 19. But perhaps the next most important is the bump map. Here, the colours in the map are interpreted by the software as either bumps or indentations in the surface. The coordinates of the vertices are not changed by the map - there are of course other techniques which do this - but the effect of bumps and indentations are created when the object is rendered. Bumps and depressions reflect light differently, and this is used to give the required effect. The rock in the lower righ t of the image of a lady standing on rocky ground in front of trees is a good example here. There is a texture map to give the colours and patterns in the rock, and a bump map to give the rock a rough-looking surface. In that image, the area to the left has not been rendered, and you can see the basic triangles from which the scene is constructed. Without bump mapping, a very much larger number of triangles would be needed to give a similar effect.



Another way of creating these effects is procedural mapping. Here, a mathematical function, or procedure, is used to create the required effect, instead of a raster image. This would not be appropriate for the logo on the side of an aeroplane - there is really only one way to do that - but it would be very suitable, for, say, the patterns in granite, or the ripples on the surface of water. One advantage of procedural mapping is its programmability. Just by changing the basic 'parameters ¬numbers - the resulting map changes; e.g. the granularity of the. granite, the colour of and contrast between the grains. Also, these parameters can be changed throughout an animation to give special effects. So, a proce¬dural map can be fine tuned in ways that are impossible with normal image-based maps. Mind you, instead of a single image, whole animations or videos can be used as a texture map, giving endless possibilities.

The two other vital components in any scene are cameras and lights. The camera is a fairly obvious concept, and is the viewpoint from which the scene is rendered. Naturally, you have considerable control over various parameters associated with any cameras - the effective focal length, position, angle of tilt, and so forth. All of these can also be animated.