Steve Baker (steve++at++mred.bgm.link.com)
Fri, 20 Jun 97 07:44:07 -0500
>> PFDECAL_BASE_HIGH_QUALITY solves the Z fighting problem, but *some* of
>> the subfaces tend to "poke through" when they should be hidden by
>> other parts of the model/scene. Is this is the problem that occurs if
>> the subfaces are not coplanar with, or bounded by, the parent face?
Marcus Barnes <marcus++at++multigen.com> replied:
> Coplanarity tolerance can be a problem for STENCIL. Performer 2.x requires a
> much tighter (truer) tolerance than 1.x did.
...I find this hard to believe. Isn't Z buffer testing disabled
when the layer polygon is rendered in STENCIL mode? I thought that was
the entire point of using STENCIL.
That being the case, surely the tolerance is unimportant. So long as the
layered polygons appear to be entirely inside the base polys, there should
be no problem.
[Of course if the layer polygons are a very large distance in front or behind
the base then parallax effects can push the layer outside the base - but
that's an extreme case]
I think Mark Baranowski's problem with STENCIL is more likely to be to
do with the layer polygons not lying entirely inside the base. That causes
some strange behaviour - especially when the layer+base are viewed in front
or behind other STENCIL mode pfLayers.
Steve Baker 817-619-1361 (Vox-Lab)
Hughes Training Inc. 817-619-8776 (Vox-Office/Vox-Mail)
2200 Arlington Downs Road 817-619-4028 (Fax)
Arlington, Texas. TX 76005-6171 Steve++at++MrEd.bgm.link.com (eMail)
http://www.hti.com (external) http://MrEd.bgm.link.com/staff/steve (intranet)
http://web2.airmail.net/sjbaker1 (external)
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