Parametric model definition

Points and transforms can be defined in terms of named variables. As lines, surfaces and bodies can be defined from points and transforms, a whole model can be created so that it is `parametric'. Also, the radii of cones, spheres and cylinders may be defined as variables, which allows points and lines defined at the intersections of such shapes to be easily adjusted. If a model is defined entirely in terms of parameters then the scale of the whole model can be readily changed, perhaps by just changing the value of a single parameter.

If a point, line, surface or body is created using a transform the relationship between the new part and the original part can optionally be stored. When this is done, a move of the original part moves the related parts; changing a transform results in points (and other parts) related to that transform also moving. Moving a point causes all points related to that point to move.