When CSG is procedural or parametric, the user can revise their complex geometry by changing the position of objects or by changing the Boolean operation used to combine those objects. CSG is popular because a modeler can use a set of relatively simple objects to create very complicated geometry. The Quake engine and Unreal engine both use this system, as does Hammer (the native Source engine level editor), and Torque Game Engine/ Torque Game Engine Advanced. Nearly all engineering CAD packages use CSG (where it may be useful for representing tool cuts, and features where parts must fit together). It is used in cases where simple geometric objects are desired, or where mathematical accuracy is important. These primitives can be combined into compound objects using operations like these:ĬSG operations being applied in the context of rays in a ray tracerĬonstructive solid geometry (CSG) has a number of practical uses. Ī primitive can typically be described by a procedure which accepts some number of parameters for example, a sphere may be described by the coordinates of its center point, along with a radius value. Some software packages allow CSG on curved objects while other packages do not.Īn object is constructed from primitives by means of allowable operations, which are typically Boolean operations on sets: union, intersection and difference, as well as geometric transformations of those sets. The set of allowable primitives is limited by each software package. Typically they are the objects of simple shape: cuboids, cylinders, prisms, pyramids, spheres, cones. The simplest solid objects used for the representation are called primitives. 4.1 Generic modelling languages and software.4 Notable applications with CSG support.

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