I use the VRayRawTotalLighting element in post-production and it is critical. This isn’t available in GPU rendering. Is there a workaround to get this element.
It’s total lighting divided by diffuse filter or raw lighting plus raw GI.
Yeah, someone mentioned that before, but I have no clue what it means. I am in Photoshop. There aren’t any raw elements, so I am assuming diffused divided by total lighting.
Are you talking VRayLighting and VrayDiffused Filter? I am so close to using GPU, but these roadblocks get in the way. I have an exterior that took 5 hours on my CPU, which is abnormally long, so I am trying GPU. It looks like GPU on my single Titan RTX will take an hour. If I can get these things working I can see getting a second Titan RTX and linking them together.
Yep - so your diffuse filter is the flat colour of your objects. The vraylighting and vrayglobalillumination passes are the colour of the object plus the intensity of light that hits it multiplied together. Thus if you have the lighting pass and the diffuse filter, you can divide the lighting by the diffuse to pull out all the colour and give you only the light part. Same trick works for the gi - divide global illumination by the diffuse filter (colour) to get only the gi light part. Likewise if you had the lighting pass and the raw lighting pass, you can divide lighting by raw lighting to get the missing bit which in this case is colour / diffuse filter.
It’s the same with your reflections too, if you have a reflection pass and the reflection filter (intensity / strength of reflection) then you can divide your reflection pass by the reflection filter and get a full strength reflection pass (kind of a chrome / mirror pass).
But how would you do this in Photoshop?
Render out a pass with a diffuse filter and a vray lighting, put the diffuse on top of the lighting pass and set the diffuse to divide. Photoshop ain’t really great for doing multipass breakapart / recombine things so you might end up doing this on it’s own, flattening the result and putting it back into your main image. Tbh for this type of thing I’d look at the free version of fusion since it’s all built for working in float with nice maths!
(p.s. this worked well with 16 bit renders, terribly with 8 bit renders - I got a lot of banding with 8 bit renders!)
I think you’ve missed the GI component? 
Vrayraw total lighting =(GI +Lighting) /Diffuse filter
I remember proposing a workaround here :
https://forums.chaosgroup.com/forum/…ng#post1049389
Doesn’t this work?
I think I missed that post. I’ll try it now.
I’m not gonna do all of bobby’s homework for him 
And for any lighting pass, whether lighting, global illumination or total lighting will give you it’s raw version if divided by the diffuse filter.