[pstricks] Opaque three dimensional surfaces.

[Herbert Voss]

Kirk Blazek wrote:

>     What I would like is for the front of the sphere to be visible, and 
> the interior of the back of the sphere to be visible through the 
> opening, but the rest to be obscured.
>     The pst-vue3d package seems to have the capability to draw spheres 
> in this opaque way, but I having two problems with this.  First of all, 
> I do not understand the angle parameters properly in the 
> \PortionSphereThreeD command.  So I can't figure out how to make it chop 
> off the top of the sphere.  The documentation doesn't seem to indicate 
> the acceptable ranges of PHI, THETA, DeltaPHI, or DeltaTHETA, and 
> trial-and-error has met with little success.
>     The second problem is that even if I can figure out how to do this 
> with a sphere, I am at a loss to do the same thing for a more general 
> parameterized surface.  In other words, I don't know how to make a 
> parameterized surface draw over and cover up things behind it, since it 
> doesn't actually draw things as grids, but as curves.

Attached is an example of Manuel, what he did
some time ago. Try to modify the code.

Herbert
-------------- next part --------------
A non-text attachment was scrubbed...
Name: sphere.png
Type: image/png
Size: 9400 bytes
Desc: not available
Url : http://tug.org/pipermail/pstricks/attachments/20060217/e834a751/attachment.png 
-------------- next part --------------
A non-text attachment was scrubbed...
Name: spherecoupe.tex
Type: application/x-tex
Size: 11280 bytes
Desc: not available
Url : http://tug.org/pipermail/pstricks/attachments/20060217/e834a751/attachment.tex