krakatoa matte objects

[phizikl]

ok, in my experience this is nothing new, but just wanted to post it,

the matte objects for krakatoa do not always work… at 2 different companies i have had issues with it, forcing me to not really use it.

if there is a certain amount of objects it seems to get buggy. i just tried adding a complete vehicle (more than 100 pieces) it will not show up as a matte object, even though matte objects explorer says its OK. i add low resolution proxy object of car as matte, no problem.

i keep low res proxy as matte, and add tires and ground, matte does not work anymore.

i have tried with several super sampling values.

have you guys never run into this?

xmeshing the scene and having “one object-xmesh” as matte will always work, but of course do not always have xmesh at disposal.

[Bobo]

Thanks for the report!
What is the total polygon count in the car example you mentioned?
I would like to create a test scene with a thousand objects and get to a point where it will stop working, but I need to know how much is too much in your case. Also how much memory did you have when that happened?

We have an open defect against Matte Objects always creating kd-trees internally (because in the past and in some cases like Spherical Lens Cameras we support raytraced Mattes), and it is possible that we are running out of resources while building all the kd-trees. But we will have to first reproduce the issue, so more info would be great!