Christian I have noticed a similar effect when having large coordinates. I think it’s a precision issue. Having objects or polygons that are overlapping or co-planar with large coordinates will give you z-fighting. Its best to group the related objects under a transform node which provides the overall offset and then the individual objects are just defined relative to the origin of the transform node.
Colin Rayment -----Original Message----- From: [email protected] [mailto:[email protected]] On Behalf Of Christian Sam Sent: 14 June 2009 23:07 To: [email protected] Subject: [osg-users] zbuffer issue Hi community, i noticed an annoying rendering problem in my application. my application is based on the osgforest example, with the difference that not every tree is represented with its own drawable, but many trees are merge into a handful of drawables, placed at a regular-grid. the rendering problem occurs only when i use real-world coordinates for the tree postions: e.g. 683006, 213213, 0. instead of "localized" equivalent of 6, 213, 0 and when using the approach described above. there are no problems when i use such large coordinates with "one-drawable per tree", like in the original osgforest implementation. it happens when i zoom in very near, the trees (only the trees, not the terrain or anything else) begin to flicker and overlapped faces of the tree's double-quads gets revealed, while others gets hidden. after i zoom out, rendering problems stops. maybe some z-buffer resolution related issue? i hope i described it in a way you can imagine it. if not i can send the whole example/resources. btw. i'm using osg-2.8.0 best regards, christian ------------------ Read this topic online here: http://forum.openscenegraph.org/viewtopic.php?p=13967#13967 This email has been scanned for all known viruses by the MessageLabs Email Security System. Please help out the environment by only printing this e-mail if absolutely necessary - Thank You. This email has been scanned for all known viruses by the MessageLabs Email Security System. Systems Engineering & Assessment Ltd - Beckington Castle, 17 Castle Corner, Beckington, Frome, Somerset, BA11 6TA, UK is registered in England and Wales with the company number 2430846. The contents of this email (including any attachments) are confidential and may be legally privileged. If you are not the intended recipient of this email any disclosure, copying, distribution or use of its contents is strictly prohibited. You should notify the sender immediately and then delete it (including any attachments) from your system. Please help out the environment by only printing this e-mail if absolutely necessary - Thank You. _______________________________________________ osg-users mailing list [email protected] http://lists.openscenegraph.org/listinfo.cgi/osg-users-openscenegraph.org
