Hi All ,
Why do geometry objects when set in a mantra ROP to be forced matte objects still appear in renders in the the default image planes N , Pz , P etc . Surely if I have set an obect to be a forced matte I should not see the geometry getting rendered in the extra image planes. Any ideas how to stop this from happening
Rob

I'm guessing it's by design (or lack of).

The matte logic seems pretty simple, as it just replaces the surface shader with a default black opaque shader. More sophisticated options (ray depth selections, etc.) would be nice. For example, the only time I ever used V-Ray, I remember there was a toggle to choose whether to remove these objects from the holdouts or not.

If you have a scene with only a few shaders it isn't too hard to add these yourself in the VOP networks.

Well its not the behavior I would of expected for sure !

Rob

Ya…I have to admit that I have been dealing with this issue lately. Not like it's a big deal as one can always mask it out but the extra file size kinda sucks. It did actually save my a$$ this week when I forgot to include some channels in a take and I could just pull 'em from a another take where I had the whole scene mostly as matte shaded.

I have also noticed that an object that's forced as a matte shaded object also gets considered when using PBR and the env light . It just doesn't make much sense at all, the desired effect should be to just act as a mask / black hole . Is there no way to make a simple “blackhole” type shader in mantra ? .

Rob

I was wondering if anyone figured out a good workflow for this issue? It's hard to use the normal/Pz pass if force matte objects are still included in it.

I get round it by having a separate mantra ROP to make all my utility passes

Rob

Did you take a look at the personnal extra image plane? You can add one and set Pz as vex variable and Float for the type or select it in the combobox. And set the Sample Filter on Full Opacity Filtering. It seems that the matte objects are removed from the render.

Opacity filter cannot be used with position/normal or other vector passes, as the anti-aliasing changes the values.

Hello, searching around this problem, is there some simple way how to exclude matte object from extra image planes? Force matte does not work, matte on object it self does not, FullOpacityFiltering on custom image plane does not work too (Vray guys make fun from Mantra, don`t like it ) Thanks a lot.

Did you guys tried that?

Houdini Light Expressions [www.sidefx.com]

mzigaib
Did you guys tried that?

Houdini Light Expressions [www.sidefx.com]

Chmm I`ll check it, thanks a lot.