vray see's only some alpha

[mikeh]

I have a scene that is using the forest plugin in max. I have one plane object with a bunch of sub-object planes scatterd around. It is a tree. For some reason, Vray ignores the alpha channel of the distant sub-object planes and sees it only on the near planes so what you get is the foreground trees show only the tree while the background trees show the tree and the black square around the tree. It is only one material for the whole thing. Any ideas?
mh

[studioDIM]

raise the max transp. levels in the vray rendering rollout, Global switches,from 50 to something bigger (500?) until the black squares disappear.
Notice the rendertime will increase a bit.

Lele

[mikeh]

Lele,
Thanks for the reply. I cranked it all the way to maximum (1000) and you were right about it slamming render times...but it did not change things. Any other thoughts?
mh

[vlado]

Increase the Secondary rays bias a bit, maybe to something like 0.001 and see if it helps.

Best regards,
Vlado

[mikeh]

WOW!... like night and day...Vray just sailed thru that image and the problem is gone. I think I'll do that to all my renderings from now on. What a difference in speed. Thanks for the tip, Vlado.
mh

[mikeh]

Ok, now there is problem #2.
With forest, there are two 2d cards at each tree. One is the shadow caster that faces the light and the other is the tree that faces the camera. They pivot at the same pt. The material is self illuminating at 100% so it should be unaffected by the shadow cast ...but for some reason, no matter what shadow type i use, the shadow blacks out the 2d card portion (tree) that is not in light so i get half illuminated trees. This was not a problem in Viz 6 with earlier vray iterations but now in Viz 7 with the latest vray it is. Any thoughts on this?
mh

[RErender]

you might try setting the "globals/secondary rays value" to .001 or .01, careful setting it too high can cause other issues

[mikeh]

Eric,
That's what Vlado suggested for the first problem which solved that...i have left the setting as he suggested and now i have the second problem...which i had before i followed his advice.
mh

[mikeh]

never mind...problem #2 solved...user error.
mh

[RErender]

heh, that'll teach me not to just scan the thread.