Hello Robert.
I digged a bit into the OSG source code and I found out that its a precision
problem. I use big models where the vertex coordinate values are >1000.
I don't know the exact process of the intersection search, but I assume that
the lineSegment is clipped in the
lineSegmentIntersector.cpp
Code:
bool LineSegmentIntersector::intersectAndClip(osg::Vec3d& s, osg::Vec3d&
e,const osg::BoundingBox& bbInput)
function to the values, where the lineSegment is slightly longer, than the
bounding sphere of the geometry.
Code:
osg::Vec3d bb_min(bbInput._min);
osg::Vec3d bb_max(bbInput._max);
#if 1
double epsilon = 1e-4;
bb_min.x() -= epsilon;
bb_min.y() -= epsilon;
bb_min.z() -= epsilon;
bb_max.x() += epsilon;
bb_max.y() += epsilon;
bb_max.z() += epsilon;
#endif
There is an epsilon value, which is currently set to 1e-4. I would suggest to
set it bigger (1e-2 f. ex.). If I change it to 1e-2, I don't get this problem
anymore.
What is the exact reason of lineSegment clipping?
Thank you!
Cheers,
Peter
Code:
------------------
Read this topic online here:
http://forum.openscenegraph.org/viewtopic.php?p=51119#51119
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