# GPU/CUDA volume and SSS support

As my fedora repos are way behind and still on blender 2.69, I've gone and compiled the latest myself. Everything seems to work and is quite recent. I can even bake CPU SSS, which is great. However I still get the error "Volumes/SSS not supported on GPU". Have I missed a flag or library (eg OSL support) in CMAKE or is this still on the todo list? If its just not finished yet, I don't mean to rush the devs but definitely looking forward to its release.

• The official Windows version of 2.70a does not support it, and the cycles release notes of 2.71 do not mention it either. I guess you still have to wait for that feature. – maddin45 Jun 4 '14 at 16:22

Unfortunately, these features aren't finished yet.

# SSS

GPU SSS is working, but still experimental. To test it, you need to add one line in the kernel_types header file:

diff --git a/intern/cycles/kernel/kernel_types.h b/intern/cycles/kernel/kernel_types.h
--- a/intern/cycles/kernel/kernel_types.h
+++ b/intern/cycles/kernel/kernel_types.h
@@ -66,6 +66,7 @@ CCL_NAMESPACE_BEGIN
#ifdef __KERNEL_CUDA__
+#define __SUBSURFACE__
#define __BRANCHED_PATH__
//#define __VOLUME__
#endif


It seems the main reason that this isn't yet included as an experimental feature is that it requires compiling kernels twice:

we cannot make it available just under experimental, we would need to compile all kernels 2x (for each architecture).

## Update:

GPU SSS is enabled in master as of this commit. Now any new development build will have SSS on GPU. This will be in 2.72.

# Volumetrics

Volume support for GPU was unofficially working shortly after its addition (see 2:22 of this video), however broke with the addition of scattering (see 2:50 of this video).

According to the same video, GPU volumetrics was supposed to be fixed for 2.70. Since that was not the case, I can only assume that development was delayed and it's still due to be fixed at some point.

## update:

GPU volume support has been added to master as of this commit, but currently is in a very experimental state and smoke/fire renders are not supported yet. This will be in 2.72.

• oh its so fast and deliciously pretty. thank you for all the info and links!! I'll be keeping an eye out for volumetrics next – jozxyqk Jun 5 '14 at 12:16
• @jozxyqk GPU Volumetrics are here now :) – gandalf3 Jul 6 '14 at 21:00