V-Ray Glare Bloom layer problem

[Robert]

Ok Vray Glare and Bloom effect can be rendered at a separate layer, but that one looks strange, instead of having the effect on a black mate I see the image with the Glare effect on top. Pretty unusable for composition, or did I miss something?
Not sure maybe a bug etc. The effect itself is useful, but really it needs to be separated for later control.

[neverko]

What I do for image compositing in Photoshop is take the rendered image without bloom/glare and stack the image with bloom/glare on top and set the top layer to difference then merge the result to a new layer. The new layer in linear dodge (add) mode can be used to control the bloom/glare over the original rendered image.

[Robert]

Yes difference is the most logical approach, but its not the best. For example, you need denoiser in your scene, the output will take all the parts from a certain selection like intensity or ID as background to the glare, but it doesn't take the denoised layer. So if you grain in your scene it comes back that way.

[John_Do]

Hey Robert,

Just set the Mode in the Lens Effect panel to Image and Render Element. It will render a specific pass with the lens effects on a black background.

[Robert]

Hi John, I tried all kind of combinations. But What ever I do I get two output a mask and Glare/Bloom output, these outputs are always on the RGB output. I render with denoiser, so its totally waste to have it on a standard RGB output. Maybe its a bug?
The only time I get a black background is when I turn off all GI and Lighting in the scene. But thats a bit contra productive.