Multi matte on objects behind refractions + other problems

[R_Cyph]

Hey,

I've got a ship that I'm created mattes for.

1) how do you get multi mattes to work for objects behind glass or transparent objects? I need the multimattes to be refracted so they line up with the refraction render element.

2) my ship is broken down in to the main geo pieces ( engine, wing, body, cockpit, tail ) each piece has multiple shaders. I only want the engine in the multi matte with materialID 1,2,3 in RGB. obviously I can't use objectID because each peice has multiple shaders. Is there a way to only connect 1 piece of geo to the multi matte render element? I don't want to use render layers with the rest of the ship hidden for each piece as that involves renders the ship out multiple times.

[bigbossfr]

Hey,

I've got a ship that I'm created mattes for.

1) how do you get multi mattes to work for objects behind glass or transparent objects? I need the multimattes to be refracted so they line up with the refraction render element.

Hi,
In your glass material --> refraction --> affect channel (all)

2) my ship is broken down in to the main geo pieces ( engine, wing, body, cockpit, tail ) each piece has multiple shaders. I only want the engine in the multi matte with materialID 1,2,3 in RGB. obviously I can't use objectID because each peice has multiple shaders. Is there a way to only connect 1 piece of geo to the multi matte render element? I don't want to use render layers with the rest of the ship hidden for each piece as that involves renders the ship out multiple times.

Add material ID on your material, enable "use materialID" on your multimatte.

[R_Cyph]

Thanks for the glass thing. Ill try that.


"Add material ID on your material, enable "use materialID" on your multimatte"

That's what I'm doing. But the same materials are being used on other parts of the ship. I just want material X , Y and Z on the engine geo in one multi matte, Then I want material X, Y and Z on cockpit in another multimatte etc. Aside from using render layers and hiding the geo you don't want is there a way of connecting just 1 piece of geo into a multimatte pass with material IDs?

[bigbossfr]

Thanks for the glass thing. Ill try that.


"Add material ID on your material, enable "use materialID" on your multimatte"

That's what I'm doing. But the same materials are being used on other parts of the ship. I just want material X , Y and Z on the engine geo in one multi matte, Then I want material X, Y and Z on cockpit in another multimatte etc. Aside from using render layers and hiding the geo you don't want is there a way of connecting just 1 piece of geo into a multimatte pass with material IDs?

1) Create a multimatte1 with "use materialID", add id for X, Y and Z material
2) Create a multimatte2, add object ID from the engine geo, add object ID from the cockpit geo

In compositing, if you want the X material from the cockpit, select the X color from the multimatte1, and select color of the cockpit of the multimatte2.

[R_Cyph]

The compositor here is saying that's going to cause a crust.
he says "Lets say I have the engine is infront of the body. They're both mostly red in the multimate because they have the same shader on the majority of the surface area. If I use another multimatte to seperate those the engine from the body its going to cause issues where the red part of the multimatte of the engine and body overlap." Is this the case?

[bigbossfr]

The compositor here is saying that's going to cause a crust.
he says "Lets say I have the engine is infront of the body. They're both mostly red in the multimate because they have the same shader on the majority of the surface area. If I use another multimatte to seperate those the engine from the body its going to cause issues where the red part of the multimatte of the engine and body overlap." Is this the case?

I do not see where is the problem.
Ask to your compositor to show us where is the problem to combine 2 masks with some images please.

[vlado]

That's what I'm doing. But the same materials are being used on other parts of the ship. I just want material X , Y and Z on the engine geo in one multi matte, Then I want material X, Y and Z on cockpit in another multimatte etc. Aside from using render layers and hiding the geo you don't want is there a way of connecting just 1 piece of geo into a multimatte pass with material IDs?

For the moment, no. You can select masks by either an object (through the object ID) or material (through the material ID), but not both. We can probably extend the multimatte to allow this and I will make a note for this. Let me know if you need it urgently and we'll see how quickly it can be added.

Best regards,
Vlado

[R_Cyph]

We did a test the mattes work fine. THANKS!


"In your glass material --> refraction --> affect channel (all)"

This makes the alpha for the glass transparent. Is there anyway to get it to affect all channels EXCEPT ALPHA?

[R_Cyph]

the combination of OBJ mattes and Shader mattes seems to be fine. although you could always add it for later. Thanks.