Vray Next - VrayOSLTex Additional Paths

[labulle]

We're trying to to convert a scene (Vray Next 4.02.05 on 3ds 2018 that quite heavily relied on the great Siger ComplexFresnel map to be used on Vray Next GPU (as it is incompatible).
We've tried to use the (also great) Reflector Tex OSL by Rens Heeren.

- I have one major problem : the OSL file (and its .h compagnon file) are not searched in usual user paths, so I tried to use the OSL Include Paths. I can't get to add any path in "Additional Paths", it's a problem with network rendering especially

- also, but it is minor of course, the VrayOSLTex has its parameters rollout last, it would be really great to have it on top for quick parameter changes, it would be consistent with other maps !

- what does it really mean that the OSLTex is "baked" before render on GPU ?

- when rendering our scene containing unsupported ComplexFresnel maps, the scene has no other problem whith stills, but there is a weird behaviour with an animation : the rendering hangs after a few frames (the fewer the objects, the further the problem appears). The scenario is always the same : after, say, 13 frames, rendering just fine and swiftly, there is a slowdown on the preparation of the next frame (Broadcasting NOTIFY_RENDER_PREEVAL in log), after a few minutes, the next frame (14) is rendered quickly and the preparation for the next frame (15) hangs indefinitely (also Broadcasting NOTIFY_RENDER_PREEVAL in log).
Obviously, it doesn't really matter in that case, but I thought It's worth sharing.

Thanks !

[kosso_olli]

This issue here might be related. The OSL path doesn't show up anywhere: https://forums.chaosgroup.com/forum/...g-specfic-file

[ikomitov]

Hi labulle,

Are you trying to add network paths? Unfortunately, the OSL compiler does not understand UNC paths, so one possible workaround is to map the network location to a separate drive letter and then add it to the list of additional paths.

Best regards,
Ivan

[labulle]

Thanks for your answer, unfortunately it doesn't work with local paths anyway. In fact, picking the OSL file in a network folder does work and is well read between network machines (even without mapping a drive letter) !

I was trying to figure out why, when I click on the "Add..." button under "Additional Paths", go to the desired folder and click on "Select Folder", the window closes and nothing happens, nothing is added.

[ikomitov]

I'll have to dig into that further. However, I cannot reproduce it. Are there any special symbols in the path? As for the rollout ordering, you are right that the current placement is inconvenient, so I'll try to move the parameter rollout to the top. Regarding the OSLTex baking - since OSL is not supported on the GPU at the moment, every OSL texture is evaluated beforehand on the CPU (as if being mapped on a plane) and the result is kept in a 512x512 bitmap which is then used during rendering. No actual OSL code is executed on the GPU. That approach has disadvantages, for example if your shader relies on the normal, the result might not be correct. It's just a workaround which allows us to render something different than black and it works fine for fairly simple textures. The size of the baking texture can be changed, you can find the corresponding setting in the Perf. tab of the V-Ray GPU settings - changing the texture mode to "Resize" will give the ability to specify another texture size.

Best regards,
Ivan