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How are object boundaries calculated?

  • Patrick

    Patrick - 2013-10-26

    Im wondering how the boundaries of an object are calculated. For instance, if I had a tetrahedron, its space would be a tetrahedron. If, however, I set the tetrahedron to triangle mesh and subdivided the edges alot, and then set the rendering to smooth, I'd get something like a reuleaux tetrahedron. Is the boundary of this object the surface, or is it the "ghost" tetrahedron it was created from?

  • Luke S

    Luke S - 2013-10-26

    It depends on what you mean by boundaries.

    First off, you don't need to subdivide a lot to get smooth edges. Just play a bit with the smoothness value on a fairly coarse mesh. (Sometimes you do need to subdivide to get exactly what you want, though...)

    • Each object has a bounding box, Which is basically a rectangular prism into which the object fits.
    • The raytracer 'sees' the smooth surface.
    • UV mapping, etc. maps the texture to the 'definition' mesh. (Unsmoothed mesh). The rendering system then maps he texture down to the smaller triangles in the smooth surface.

    It might help a bit to know what exactly you mean when you say 'boundary'


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