Ken wrote:

> One of
> the very nice features of a lathe object is the high
> order math functions used in their implementaion.
> The surface smoothness is equal to that of the sphere
> object. Meshes, patches, polygons, and the other methods
> notoriously have a problem with faceting because they
> are constructed from flat surfaces.
> 
>   So I guess the question is are they all comparable
> or are you trading quality for speed ?

Jaime Vives Piqueres wrote meshlath.inc because the lathes, at least
when used to make glass objects, were slow enough to make the scene
unrenderable.  With meshes, the bottles were much faster.  The
triangulation method of meshlath.inc is partly based on that in my old
cylindrical height field include file (and some neat spline macros). 
With this method you can generate subpixel size triangles if you want. 
Obviously, you have no faceting artifacts if you do this.  You can
adjust the fineness to taste.  Incidentally the include generates
smooth_triangles, further reducing any potential faceting.  The downside
is that you take a parse time hit with superfine meshing.  On the other
hand, the render time improvement of mesh over lathe, in my experience
so far, still produces a net speed benefit (and avoids some potential
"issues" with lathes).  Another benefit is the ability to use Cardinal
splines, Beta splines, Tau splines and others by simply dropping in a
different basis matrix.  This allows smoother and more controllable
shapes, depending on what you are modelling.  Jaime has created a very
useful tool.

Jerry Anning
cle### [at] dholcom

Post a reply to this message