Java3D only does view frustum culling, no occlusion culling.  You can solve
the problem by building a spatial tree like an oct tree using the bounds of
the shapes and then using a switch node to turn off hidden shapes.

Dave Yazel

----- Original Message -----
From: Adrian Meekings <[EMAIL PROTECTED]>
To: <[EMAIL PROTECTED]>
Sent: Sunday, November 11, 2001 11:49 PM
Subject: [JAVA3D] Shape3D Culling, Quick lesson required please


Hello all

It appears to me that all Shape3Ds in the view volume are sent to the video
card for rendering regardless of wether or not they are hidden behind other
shape3Ds(?) The videocards Z buffer then decides wether or not the objects
should be rendered (??).

I found this apparant behavior by trying everything to speed up the
rendering on my project - A viewPlatform sweeping over a table surrounded by
8 chairs.
First
By turning off the canvas3Ds double buffering I could witness each hidden
object being rendered first.
Second
I used an OrderedGroup instead of a transformGroup to get the hidden objects
"rendered" last. This worked as far as rendering order however the rendering
speed was just as slow as ever. Hence my belief that Java3D still sends the
Shape3Ds to the card. (Correct?)

Is it possible to speed up rendering by getting Java3D to determine weather
or not a shap3D is hidden (or partially hidden) and therfore not rendering
(or partially rendering it) Just like it does with Hidden Surface removal.
Unfortunately the objects are manipulated at run-time so I cant make them
all one Shape3D and use the HSR of Java3D.

Thanks for your help
Adrian












Confused

Adrian

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