RT GPU: Procedurals in Bump Slot

[kosso_olli]

I found out that they are not working. Why is that? Is there a known workaround?

Regards

Oliver

[savage309]

Yes, this is still in the todo list (you can check here for complete list of supported features http://docs.chaosgroup.com/display/V...orted+Features) and you can use only plain bitmap images for bump maps.

[kosso_olli]

Yes, this is still in the todo list (you can check here for complete list of supported features http://docs.chaosgroup.com/display/V...orted+Features) and you can use only plain bitmap images for bump maps.

Oh. That's quite a dealbreaker for me, because I use a slight noise in nearly every automotive material I have. Can you estimate how long it would take to support the basic things like noise (even better BerconNoise), cellular, smoke?

Edit: Erm, on the page it says that noise is supported. But I have a scene here where it doesn't work. Bitmap however does.
Edit2: On the botton page it says not for bump. Sorry.

[savage309]

Oh. That's quite a dealbreaker for me, because I use a slight noise in nearly every automotive material I have. Can you estimate how long it would take to support the basic things like noise (even better BerconNoise), cellular, smoke?

Edit: Erm, on the page it says that noise is supported. But I have a scene here where it doesn't work. Bitmap however does.
Edit2: On the botton page it says not for bump. Sorry.

If we make the support for the procedural textures as bump maps, all of the supported procedurals will start work. It is pretty high in the todo list, but I can't give any estimations at the moment.

[super gnu]

yes the limited bump mapping on gpu is a pain.. i cant pretend to understand why it didnt come at the same time as diffuse mapping support (it would be more clear and straightforward if maps became supported simultaneously in all uses) but good to hear there is no fundamental issue with fixing it, and that its high up on the list

[kosso_olli]

Hope it can be done or the next release. Looking forward to it!

[Alan Iglesias]

I found out that they are not working. Why is that? Is there a known workaround?

This may very well not be a sophisticated enough work-around for your application Oliver, but just in case it helps somewhat... I have baked a number of different and (depending on the need) fairly large noise maps to bitmaps and am using them with some success with RT/GPU - I find they can be especially helpful in the bump slot.

Just in case you haven't tried this yet...

-Alan

[vlado]

In the latest builds, you can also use the VRayTriPlanarTex texture with a Bitmap in it for bump mapping.

Best regards,
Vlado

[kosso_olli]

Thanks for the pointer! Problem is that every bitmap will show some tiling artifacts every now and then, no matter how big I bake these out. Procedurals are a huge help there.

[vlado]

Thanks for the pointer! Problem is that every bitmap will show some tiling artifacts every now and then, no matter how big I bake these out. Procedurals are a huge help there.

Yes, there is that. We'll get to it for the next SP, hopefully. My main issue is that bump mapping happens in totally different ways f.e. in 3ds Max and Maya and we have to complicate our GPU code to handle both methods...

Best regards,
Vlado

[super gnu]

Yes, there is that. We'll get to it for the next SP, hopefully. My main issue is that bump mapping happens in totally different ways f.e. in 3ds Max and Maya and we have to complicate our GPU code to handle both methods...

Best regards,
Vlado

why is that? id assume since the bump mapping is a rendertime effect, and the renderer in both cases is vray, a single method would suffice?

[vlado]

why is that? id assume since the bump mapping is a rendertime effect, and the renderer in both cases is vray, a single method would suffice?

Well, because for better or worse, we tried to keep the bump as close as possible to the native renderers in the different applications...

Best regards,
Vlado

[Alan Iglesias]

Thanks for the pointer! Problem is that every bitmap will show some tiling artifacts every now and then, no matter how big I bake these out. Procedurals are a huge help there.

Yeah, I hear you. My biggest problem has been just that - being able to see the visible border lines of the bitmap as it tiles.

But Vlado says he is getting the Tri-Planar map working with it and that just may do a good job of blending the maps as they tile, at least in some applications. I look forward very much to trying it.

-Alan

[super gnu]

ok understood.. out of interest, which has "better" bump mapping? maya or max?

[vlado]

ok understood.. out of interest, which has "better" bump mapping? maya or max?

None of them is "better"; they are just different. F.e. in 3ds Max, bitmaps have a special "bump" output that may be different from the color/mono output of a texture. This makes the evaluation of bump mapping somewhat faster, as the texture tree needs to be evaluated just once and maybe special optimizations can be done for bump calculations, but on the other hand this can lead to some discrepancies (f.e. the ColorCorrection texture has no effect on bump mapping at all; the bump of the Cellular texture is wrong and is not the same as baking the texture to bitmap and using that as bump, and so on). In Maya, the bump is implemented similar to the VRayColor2Bump shader where the entire texture tree is sampled at several different points to determine the bump mapping. This is more accurate and allows any texture trees to work correctly, but is somewhat slower.

Best regards,
Vlado