Re: Occulting problems with polygon subfaces in Performer

New Message Reply Date view Thread view Subject view Author view

Jude Anthony (jude++at++p3.enzian.com)
Wed, 16 Oct 1996 08:56:08 EST

Hi. We've been having similar problems with coplanar faces. We
found that even separating the polygons will not necessarily stop the
effect, which is called Z-fighting or "flimmering." (I'm not making
this up.) Sometimes reducing the distance between your near and far
clipping planes can make a difference, as can increasing your
Z-buffer bits. Sometimes separating the faces can help.

There are only two certain fixes that we have found for this
behavior. The first is to change the mode used with subfaces (I'd
tell you the name of the function and mode, but we're doing
cold-start and I can't find it. If no one else comes up with it,
I'll tell you next week). That method often requires extra app time.
 The other possibility is to actually cut the subface out of the
geometry (so there's nothing behind it to fight with). This adds
some polygons, and therefore some draw time, but we minimized the
impact by making certain we meshed properly. In fact, with a
visible database often exceeding 10,000 polygons, the extra eight or
ten was insignificant.

Good Luck!
Jude Anthony
jude++at++p3.enzian.com
=======================================================================
List Archives, FAQ, FTP: http://www.sgi.com/Technology/Performer/
            Submissions: info-performer++at++sgi.com
        Admin. requests: info-performer-request++at++sgi.com

New Message Reply Date view Thread view Subject view Author view

This archive was generated by hypermail 2.0b2 on Mon Aug 10 1998 - 17:53:46 PDT

This message has been cleansed for anti-spam protection. Replace '++at++' in any mail addresses with the '@' symbol.