Composition tag on material – is it possible?

[Adam Trachtenberg]

No, not possible. You’d have to render twice.

[Richard Quinn]

Hi Adam,

Thanks for the prompt reply.

How could I achieve this with 2 renders?

How can I make only the stars render on there own if they are wrapped around the hat object.

I just tried applying a luminance channel with 100% white to the area around the stars thinking that might render out as an alpha. However the post effects could see it and the highlights went crazy.

Cheers,

Rich

[Adam Trachtenberg]

What I would do is create a separate material of just the stars in the luminance channel — white on black. Apply it to your object and render out a material:luminance pass. Delete all of the other materials from your scene. In fact, you can delete all objects that don’t pass in front of your object to speed up the render. Then use the luminance pass to apply the effect.

[Richard Quinn]

Hi Adam,

I am a little confused.

Once I have rendered out the white stars having put the texture in the luminance channel of the material.

I have then enabled Material luminance in the multipass render settings and rendered it out.

What do I do with the render to then apply the post effect? Are you talking about going into after effects or can it still be done in C4D?

Sorry for my lack of understanding.

Cheers,

Rich

[Adam Trachtenberg]

Yes, I’m talking about using it as a luma matte in AE. I thought that was what you were trying to achieve?

[Richard Quinn]

Hi Adam,

My aim was to add a Cinema 4D post effect such as “highlight” to my stars on my hat. The stars are on a material though. I know you can’t add an object buffer to a material but wondered if there was work around within C4D.

Cheers,

Rich