Kathryn Loynes (kathyl++at++wormald.com.au)
Wed, 19 Oct 1994 14:54:00 +1000 (EST)
I am currently attempting to implement some routines which intersect
line segments against objects with multiple LODs.
According to the man pages and Programming Guide the intersection
traversal will always intersect with the highest level-of-detail model.
However, in the interests of speeding up the intersection traversal I was
wanting to intersect always against the *lowest* level-of-detail in a
model. The suggested method for doing this appears to be to duplicate the
LOD node with a Switch node (same parent & children). Then turn off the
intersection mask totally for the LOD and set the Switch node to
whichever child you want to intersect against.
My question is why do you need to have the Switch node at all ? Each
child under the LOD node has its own intersection mask. Why not simply
mask out intersections for all except the desired child (lowest
level-of-detail) ? Would this force the isect traversal to use the correct
child or would it still select the highest level-of-detail child, discover
it was masked out & then abandon the intersection testing?
Thanx for all help.
----------------------------------------------------------------------
Kathy Loynes | Wormald Technology
kathyl++at++wormald.com.au | Advanced Systems Engineering
Ph: +61 2 981 0611 | Sydney, Australia
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