Re: culling errors for dynamic geometry

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From: Bram Stolk (bram++at++sara.nl)
Date: 04/12/2000 06:03:09

Brian Furtaw wrote:
>
> I have seen this CAVE problem with text strings rendered by Performer,
> are you having this problem with pfText nodes? I suggested to the
> developer with the problem that first they turn off culling for those
> nodes to prove that it is in fact a culling problem. Then if that works
> check to see if the bounding volumes are DYNAMIC and not STATIC on the
> pfText nodes. Finally make sure the bounding volumes are large enough by
> experimenting with there size.

First, they are not text nodes.
I experience this with LineSet geosets, and triangle/polygon sets.

And it gets weirder and weirder:
When specifying a huge bounding volume, the culling for the linesets
disappears. However, the culling for the polygons remains.
For both pfGeoSets, I force the recomputation of the bounding box
as described by the manual.

The erroneous culling depends on two things:

-1- proximity of viewpoint to object (close: error, far: ok)
-2- the amount of positional change of the vertices. (much: error, little: ok)

    Bram 

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 Bram Stolk, VR Specialist.
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