Prev Next 6.5.6 Constructive Solid Geometry In addition to all of the primitive shapes POV-Ray supports, you can also combine multiple simple shapes into complex shapes using Constructive Solid Geometry (CSG). There are four basic types of CSG operations: union, intersection, difference, and merge. CSG objects can be composed of primitives or other CSG objects to create more, and more complex shapes. 6.5.6.1 Inside and Outside Most shape primitives, like spheres, boxes and blobs divide the world into two regions. One region is inside the object and one is outside. Given any point in space you can say it's either inside or outside any particular primitive object. Well, it could be exactly on the surface but this case is rather hard to determine due to numerical problems. Even planes have an inside and an outside. By definition, the surface normal of the plane points towards the outside of the plane. You should note that triangles and triangle-based shapes cannot be used as solid objects in CSG since they have no well defined inside and outside. Note: : Although triangles, bicubic_patches and some other shapes have no well defined inside and outside, they have a front- and backside which makes it possible to use a texture on the front side and an interior_texture on the back side. | |
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