Blender Git Loki

USD import cleanup: reorder include.

Array Brush: Initial radial and linear array editing

USD Import: fix comments.

Now using C-style comments throughout. Also,
putting unused code in #if 0 blocks. Removed
unneeded comments and other miscellaneous fixes.

Merge branch 'master' into soc-2021-porting-modifiers-to-nodes-remesh-blocks

# Conflicts:
# source/blender/blenkernel/BKE_node.h

Merge remote-tracking branch 'origin/soc-2021-porting-modifiers-to-nodes-merge-by-distance' into soc-2021-porting-modifiers-to-nodes-merge-by-distance

Geometry Nodes: Merge by Distance (Direct Modifier Port)

This patch is a direct port of the Weld modifier that moves the
common code to the geometry module.
I had made another version of a Merge by Distance Modifier (D10888), with an own implementation,
but I found that the original modifiers algorithm gives finer results.

Differential Revision: https://developer.blender.org/D12019

Fast Multiple Strip THumbnail caching job - V2 plus cleanup

Cleaned up code. Much faster caching of thumbnails. Changed old thumbnail
cache limit checking code. Shift some operations to separate functions

Merge branch 'master' into soc-2021-vse-strip-thumbnails

Cycles X: restore support for rendering SSS inside volumes

I found no GPU rendering performance difference in the two benchmark scenes
with SSS: junkshop and monster. In scenes with overlap between SSS and volumes
there will of course be a slowdown.

There is test reports/T39823 for this, which now seems to work correctly.

Differential Revision: https://developer.blender.org/D12017

Merge 'master' into soc-2021-curves branch

Merge branch 'master' into soc-2021-curves

Cycles X: don't use ray position when sampling light for volume segment

Area light solid importance sampling can introduce a lot of noise otherwise
if the ray start position happens to be close to the light, but the volume
segment also passes closely to other parts of the area light.

Ref D11845

Cycles X: add volume multiple importance between equiangular and distance

Ref D11845

Cycles X: add equiangular volume sampling for direct light

Indirect always uses distance sampling.

Ref D11845

Cycles X: refactor to separately track direct and indirect in volumes

So that we can scatter at two different positions.

Ref D11845

Cycles X: sample position on light before stepping through volume

In preparation of equiangular sampling.

Ref D11845

Cycles X: tweak light functions in preparation of equiangular sampling

* Add function to sample a new position on a given light
* Tweak shadow ray generation to be able to override the position

Ref D11845

Cycles X: copy volume phase functions to smaller ShaderVolumePhases struct

Will be important to reduce memory usage in upcoming commits.

Ref D11845

Compositor: Full frame Track Position node

Adds full frame implementation to this node operation.
No functional changes.

Interpolate tilt, radius and weight in curve cut