When enabled, this normalize the strength by the light area, to keep
the total output the same regardless of shape or size. This is the
existing behavior.
This is supported in Cycles, EEVEE, Hydra, USD, COLLADA.
For add-ons, an API function to compute the area is added for conversion,
in case there is no native support for normalization.
area = light.area(matrix_world=ob.matrix_world)
Co-authored-by: Brecht Van Lommel <brecht@blender.org>
Pull Request: https://projects.blender.org/blender/blender/pulls/136958
There is a corner case where one side of a quad needs splitting and the other
side has only one segment. Previously this would produce either gaps or after
recent changes to stitch together geometry, uninitialized memory.
Now solve this by splitting into triangular patches, as suggested in the
DiagSplit paper. These triangular patches can be further subdivided themselves.
Dicing has special cases for 1 or 2 segments on edges. For more segments it
works the same as: quad dicing: A regular inner triangle grid stitched to the
outer edges.
Fix#136973: Inconsistent results with adaptive subdivision
Pull Request: https://projects.blender.org/blender/blender/pulls/139062
In Cycles, the convention is that reflection vs. refraction are classified
based on the hemisphere defined by the *shading* normal (N).
In general, most closure code uses the shading normal for most operations,
as is expected since using the geometric normal (Ng) would break normal maps
and smooth shading.
However, there are two places that use Ng: On the one hand, BSDF sampling
functions generally reject reflections that fall below the Ng hemisphere, since
they'd intersect the geometry when tracing the bounce. This is required, and
we can't do much about it.
On the other hand, the Microfacet evaluation code also checked that the ray
is in the same hemisphere w.r.t. both shading and geometric normal.
Theoretically, this is the right thing to do, since sampling and evaluation code
are supposed to be consistent. However, doing so breaks smooth shading, since
now direct light evaluation near the terminator will sometimes be rejected.
This didn't cause problems in practice because of another inconsistency: While
the parameter of the eval functions was named Ng, the caller actually provided
N (unclear whether by mistake or as a hacky workaround to the terminator).
When this was fixed in 063a9e89, users quickly reported issues with the shadow
terminator, so it was reverted to the hacky inconsistency in 1c50dd8b.
So, let's clean this mess up properly. If we don't want to do the Ng hemisphere
check in _eval, then instead of passing in a misleading value that ends up
making it a no-op, just remove the check. After all, the other closures don't
perform it either.
This way, we avoid the mislabeled Ng, we get rid of the special case for
microfacets, and the shadow terminator continues to be fine.
Technically, we still have the _sample vs. _eval mismatch. However, this is just
unavoidable, and is irrelevant in practice: For a strongly directional light
that makes the shadow terminator noticeable, the MIS weights will be massively
in favor of eval, to the point that it doesn't really matter what sample does.
To support this argument: You can actually reproduce a broken shadow terminator
in pretty much every Cycles version going back to 2011 by just setting up a
small intense mesh emitter, turning off MIS on it to disable _eval, and then
rendering a diffuse smooth-shaded sphere with >100000 samples so that the
fireflies resolve into somewhat consistent lighting.
If nobody has complained about this affecting all closures for 11 years,
I guess it's fine.
Pull Request: https://projects.blender.org/blender/blender/pulls/138632
Switch from Standard Surface to OpenPBR as the exported MaterialX surface,
since this is the new standard more renderers are adopting and it more closely
matches the Principled BSDF implementation.
Anisotropy support is improved though still not quite the same, as formulas
are different. Nodes are generated to apply anisotropic rotation to the
tangent vector, as there is no corresponding parameter in OpenPBR.
Fixes#138164
Authored by Apple: Lee Kerley
Pull Request: https://projects.blender.org/blender/blender/pulls/138165
There was one test in the volume render test folder that made use of
the ocean sim modifier to add some detail. This lead to test failures
when building Blender without ocean sim.
To fix this issue, this commit applies the ocean sim modifier. This
means it's no longer used, but the render results are the same,
meaning there is no need to update the reference images.
Pull Request: https://projects.blender.org/blender/blender/pulls/138729
Add a new shader node to control volume coefficients (scattering,
absorption and emission) directly, making it easier to model existing
volumes with measured data.
Pull Request: https://projects.blender.org/blender/blender/pulls/136287
Note: this is a partial fix, that makes NEE and forward path consistent
only when `max_transparent_bounce > 0`. It is much more involved to make
forward path tracing support a max transparent bounce of 0, but since we
don't expect people to set up a very low number of transparent bounces,
it is less important to support that specific case.
Pull Request: https://projects.blender.org/blender/blender/pulls/138098
This change moves the tests data files and publish folder of assets
repository to the main blender.git repository as LFS files.
The goal of this change is to eliminate toil of modifying tests,
cherry-picking changes to LFS branches, adding tests as part of a
PR which brings new features or fixes.
More detailed explanation and conversation can be found in the
design task.
Ref #137215
Pull Request: https://projects.blender.org/blender/blender/pulls/137219
