Redshift Cryptomatte Custom Name ID

[freejonah]

When rendering in Redshift, in the rop under the AOV section you can select cryptomatte as a custom output. There are four ID Type options you can choose from:

1. Node Name
2. Material Name
3. Object ID
4. Custom Name ID

Does anybody know how to make option #4 work? It seems like there's a very powerful component to the cryptomatte functionality that nobody is using, unless i'm mistaken. There's no better program than Houdini at making carefully placed and named attributes, but what do you do? I tried making a primitive attribute called "Name" but that did nothing. Is this even implemented in Houdini?

 

[Sepu]

This has nothing to do with Houdini btw - is redshift. The way that works as of now is on the OBJ level "cryptomatte ID" 

Now if you want to get it working something in SOPs you need to enable the instance packed geo option and also the "Create Cryptomatte Material IDs From Not Available Materials" (which is one by default in also in .66 or earlier) option in the obj properties. And make sure that you change the instance method from PC to redshift instance.  Then create an attribute s@shop_materialpath which will be your geo basically. Then in AOVs pick "material name".  Anyway attached is an example of this workflow in RS.

Well, this last one depends on what version of RS you are using since it changed the defaults to PC which is faster to render a huge amount of instances. Also this workflow usually you will need two ROPs a bty and the cryptomatte ... but it works 

rs_cryptomatte.hip

[freejonah]

On 4/4/2022 at 10:36 PM, Sepu said:

Now if you want to get it working something in SOPs you need to enable the instance packed geo option and also the "Create Cryptomatte Material IDs From Not Available Materials" (which is one by default in also in .66 or earlier) option in the obj properties. And make sure that you change the instance method from PC to redshift instance.  Then create an attribute s@shop_materialpath which will be your geo basically. Then in AOVs pick "material name".  Anyway attached is an example of this workflow in RS.

Hey this is really helpful. I loaded your file and rendered it and it looks correct, so that's great. I have a couple of questions.

I don't see "Create Cryptomatte Material IDs From Not Available Materials" anywhere on the .obj properties area. I assume that's because I'm using Houdini 18.5.633 ? Anyway it seems to work so the default must be fine.

But this is a really interesting methodology. I am not actually doing any instancing, but the methodology works fine when you just add a random "shop_materialpath" primitive attribute to the primitives themselves. Here is the pig head copied without any instancing at all. Just 88,000 polygons copied on points. Works like a charm. Obviously it screws with your actual rgb pass but as you said you can run out separate passes.

[Sepu]

I can't remember when it came out. I'm pretty sure is fine and it should work in 18.5.

Yeah having to render twice is the working around for now if you want to use this with RS - This is just for RS other renders support this without this. WE might a an update very soon that might update this workflow 

[valentin]

Hello, I have the same kind of problem. I need to export RSproxy, I have a customID attribute on the points, and I would like to make a cryptomatte pass that depends on this customID attribute without losing the already assigned shader

Edited October 1 by valentin