Bump as a render element, and NOT on the material?

[Laserschwert]

Is it possible to have the bump map NOT show any effect on the material, but have a render element, that contains only the bump (basically a black and white image, that shows the bump effect with the scene's lighting)? Is there some way via VRayExtraTex?

[vlado]

basically a black and white image, that shows the bump effect with the scene's lighting

Can you show me what this will look like?

Best regards,
Vlado

[Laserschwert]

I can't really reproduce it... this is a quick Photoshop mockup:



Technically this is a solid grey ( 128/128/128 ) image, where only the lighting differences caused by the bump map are visible (so no shadow/light effects you can normally find with the diffuse lighting elements). The idea is to have the "unbumped" rendering, and overlay this "bump element" in Photoshop or AfterEffects to fake the effect of bump map (only in luminance - changed reflections don't matter here).



The Photoshop mockup is faked using the "relief" filter (on a VRayExtraTex-noise, see below, which would basically be my bump) with the light coming from the right, but the render element would of course have to take all lights into account (which in this case would be two - one from the left, one from the right).

[Pixelcon]

The way I've done this sort of thing in the past is to put the map (your bump map in this case) into a vrayextratex element. It will use the mapping from each object and apply the defined map to the entire scene. Then use a simple mask to get the bump map for your specified object. You can turn off your bump map in the material and it will still work in the extra tex.

I once used this method to create a mask for an object that was using an opacity map.

Hope this works for you!

edit: now I see you're concerned about lighting. Im not sure if the above method will work without using some lighting elements... Perhaps a normal element is heading down the right path...

[Laserschwert]

The way I've done this sort of thing in the past is to put the map (your bump map in this case) into a vrayextratex element. It will use the mapping from each object and apply the defined map to the entire scene. Then use a simple mask to get the bump map for your specified object. You can turn off your bump map in the material and it will still work in the extra tex.

I once used this method to create a mask for an object that was using an opacity map.

Hope this works for you!

edit: now I see you're concerned about lighting. Im not sure if the above method will work without using some lighting elements... Perhaps a normal element is heading down the right path...

Yeah, my problem is not getting the raw bump map out (as you can see the bottom image is just what you suggest, a VRayExtraTex. Masking that one afterwards to the desired objects wouldn't be a problem). The point is, I need the actual bump effect. Using VRayBumpNormals doesn't help, as this doesn't contain any light information from the scene, but would only allow me to manually place lights afterwards (with a plugin like Normality for AfterEffects, for example). Also the bump effect looks different depending on the size of a light, so I some need this thing to be rendered along with the actual image, to take the scene lighting into account.

[Laserschwert]

Edit: Never mind, I was wrong.