[x3d-public] Question about parametric primitives

[Christopher Bruns]

I'd appreciate some advice about how to use the X3D format.

I'm developing some renderers that use non-mesh display methods for certain
parametric primitives, including spheres, cylinders, truncated cones, and
infinite planes. And I'm considering using X3D as my scene file format. I'm
pleased to see that parametric representations for spheres and cylinders,
at least, are available in X3D. I suspect that I could represent parametric
truncated cones using either 1) a cone primitive plus a clip plane, or 2) a
cylinder with a projective transformation. But I would prefer a more direct
semantic representation of a truncated cone. Is there a way to explicitly
represent a parametric truncated cone?

A possibly more difficult problem is representing an infinite plane as a
scene object. I wonder if perhaps some sort of degenerate NURBS surface
might represent an infinite plane? Alternatively I could represent a plane
using a single vertex plus a normal vector, along with some sort of
annotation. Is there a more direct way to represent an infinite plane in
X3D?
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