RT: Layered texture, ramp not supported?

[Fredrik Averpil]

Hi,

My colleague, Simon Algehov, is having problems rendering a certain shading network with rtEngine/CUDA. Perhaps it is not supported?
I've asked him to elaborate further in this thread.

I'm attaching the scene and textures as well as screenshots and an error in the output (No image writer specified). The ball in the render should be blue-ish, not white.

Scene file: https://mega.co.nz/#!blAjwR6T!6edmjb...vTVpraTN7iLDME

RT RENDER:

V-Ray: Starting render
[2015/Jun/8|15:20:46] V-Ray: Exporting scene to V-Ray.
[2015/Jun/8|15:20:46] V-Ray: Parsing light links time  0h  0m  0.0s (0.0 s)
[2015/Jun/8|15:20:46] V-Ray: Translating scene geometry for V-Ray
[2015/Jun/8|15:20:47] V-Ray warning: Rendering SubD Surfaces is disabled in RT. To enable it go to: Render settings -> RT Engine -> Geometry -> Subdivision
[2015/Jun/8|15:20:47] V-Ray: Total time translating scene for V-Ray  0h  0m  0.1s (0.1 s)
[2015/Jun/8|15:20:47] V-Ray: Rendering with IPR (port 20207).
[2015/Jun/8|15:20:47] V-Ray: Clearing bitmap cache memory...
[2015/Jun/8|15:20:47] V-Ray: Updating frame at time 1.00
[2015/Jun/8|15:20:47] V-Ray:  (Estimated time remaining:  0h  0m  3.3s): 1 % completed
[2015/Jun/8|15:20:47] V-Ray:  (Estimated time remaining:  0h  0m  0.2s): 40 % completed
[2015/Jun/8|15:20:47] V-Ray: Total time updating frame  0h  0m  0.2s (0.2 s)
[2015/Jun/8|15:20:47] V-Ray: Render complete
[2015/Jun/8|15:20:47] V-Ray: ========================
[2015/Jun/8|15:20:48] V-Ray warning: [SettingsEXR] No image writer specified.
[2015/Jun/8|15:20:48] V-Ray warning: [SettingsPNG] No image writer specified.
[2015/Jun/8|15:20:48] V-Ray warning: [SettingsJPEG] No image writer specified.
[2015/Jun/8|15:20:48] V-Ray warning: [SettingsSGI] No image writer specified.
[2015/Jun/8|15:20:48] V-Ray warning: [SettingsTIFF] No image writer specified.
[2015/Jun/8|15:20:48] V-Ray warning: [SettingsTGA] No image writer specified.
[2015/Jun/8|15:20:48] V-Ray: Preparing renderer...
[2015/Jun/8|15:20:48] V-Ray: Preparing scene for rendering...
[2015/Jun/8|15:20:48] V-Ray: Creating texture cache with size 0 MB
[2015/Jun/8|15:20:48] V-Ray: Creating bitmap manager
[2015/Jun/8|15:20:48] V-Ray: 2 lights found.
[2015/Jun/8|15:20:48] V-Ray: CUDA renderer requested.
[2015/Jun/8|15:20:48] V-Ray: dr host: 127.0.0.1:20207
[2015/Jun/8|15:20:48] V-Ray: Connected to render host 127.0.0.1:20207
[2015/Jun/8|15:20:48] V-Ray: Using 1 hosts for distributed rendering.
[2015/Jun/8|15:20:48] V-Ray: Max ray intensity is enabled: rendered result may have incorrect brightness.
[2015/Jun/8|15:20:48] V-Ray: Using embree ray tracing.
[2015/Jun/8|15:20:48] V-Ray: Server 127.0.0.1:20207: Scene loaded; starting render
[2015/Jun/8|15:20:48] V-Ray: Server 127.0.0.1:20207: Starting frame 1
[2015/Jun/8|15:20:49] V-Ray: Running RTEngine
[2015/Jun/8|15:20:49] V-Ray:

rtEngine/CUDA:


CPU:


Shading network:

[Algehov]

I never get RT on GPU to look the same as on CPU (or rendering normally).

I think I've figured out 2 related issues that might not be supported on the GPU (which I use frequently when shading).
First of all, Layered Texture seems to mess with the result ALOT, making the shader completely different (and all the render elements) on GPU.

Another thing I often do, is convert a texture into a ramp (with rgb to hsv then into a ramp). If you connect textures into that ramps color after that, it looks like only the texture on position 0 gets rendered, and not the whole ramp-result) On GPU that is. Everything works as expected with RT on CPU.

I've always heard so much praise on how good GPU-rendering is now. Pretty much everyting is supported except OSL, and its so much quicker, etc. But it always looks completely different when I try anything more complex than a default material on a sphere. So I hope these issues can get cleared up. Perhaps its me doing something wrong, or having to change some RT settings.

[vlado]

Thanks for the scene, Fredrik - will look into it.

Best regards,
Vlado

[georgi.zhekov]

Hello,

For now Ramp in layered texture is not supported on the GPU. It's on our "to do" list, though. I'll make a note to bump it and will notify you when it's fixed.

Best regards,

[Algehov]

Nice, that's good to hear Georgi.

Ramp in a layered texture isn't the only place where it renders incorrectly however.

I numbered two places in the shader which will render incorrectly on GPU in the attached image.
Just wanna make sure that you are also aware of that nr 1 in the image will also give a wrong result. Plug ramp343 straight into the gamma nod and bypass the layeredTexture and you'll see the difference.

[georgi.zhekov]

Thanks for pointing it out, I missed that one! I'll look into that.

[Algehov]

Great! Looking forward to hear how it goes.

[georgi.zhekov]

There seems to be some issues with ramp mapped with remapped ramp, it's in the bug tracking system already and the devs are on it.

Thank you,

[georgi.zhekov]

Hello,

Just wanted to let you know that the issues regarding your scene are now resolved and the fix will be included in the next SP.

Thank you,

[Fredrik Averpil]

Excellent, thanks.