Black area when billboards overlap...any ideas??

[RSF]

Hello!
I'm using many billboard trees to populate a scene.
Sometimes a billboard overlaps another and the area where they're overlaping becames black and not transparent.
I guess this is usual but...is there a way to avoid it?
With the scanline renderer and raytraced shadows this doesn't happen.
Is it possible that two coincident transparent faces continue to be transparent instead of black?
I'm just trying to avoid checking a large scene for these situations :-S
Thanks

[Syclone1]

you could try changing the Secondary Rays Bias under global settings to something like 0.001 or 0.0001. That usually takes care of coplaner faces.

-dave

[RSF]

Thanks

[dbuchhofer]

if you're so inclined C:\3dsmax7\scripts\examples has one 'Example_RandObjects.ms' with an interesting function for cleaning up objects with overlapped bounding boxes.

haven't made anything useful of it yet, but it sounds good!

from the script comments..
-- This is a scripted utility that can be used to generate a random set
-- of copies of a picked object. Once created, you can twiddle the
-- spinners to make live changes to the copy count and position
-- and rotation spreads. It also has a prune-overlaps button which
-- using an intersection pruning function you might find generally
-- useful.

[olitech]

...you could also increase the 'max. transp. levels' under the global switches parameter