It is basically brute force volume scattering within the mesh, but part
of the SSS code for faster performance. The main difference with actual
volume scattering is that we assume the boundaries are diffuse and that
all lighting is coming through this boundary from outside the volume.
This gives much more accurate results for thin features and low density.
Some challenges remain however:
* Significantly more noisy than BSSRDF. Adding Dwivedi sampling may help
here, but it's unclear still how much it helps in real world cases.
* Due to this being a volumetric method, geometry like eyes or mouth can
darken the skin on the outside. We may be able to reduce this effect,
or users can compensate for it by reducing the scattering radius in
such areas.
* Sharp corners are quite bright. This matches actual volume rendering
and results in some other renderers, but maybe not so much real world
objects.
Differential Revision: https://developer.blender.org/D3054
Previously we stored each color channel in a single closure, which was
convenient for sampling a closure and channel together. But this doesn't
work so well for algorithms where we want to render multiple color
channels together.
commit 90778901c9
Merge: 76eebd93bf0026
Author: Schoen <schoepas@deher1m1598.emea.adsint.biz>
Date: Mon Apr 3 07:52:05 2017 +0200
Merge branch 'master' into cycles_disney_brdf
commit 76eebd9379
Author: Schoen <schoepas@deher1m1598.emea.adsint.biz>
Date: Thu Mar 30 15:34:20 2017 +0200
Updated copyright for the new files.
commit 013f4a152a
Author: Schoen <schoepas@deher1m1598.emea.adsint.biz>
Date: Thu Mar 30 15:32:55 2017 +0200
Switched from multiplication of base and subsurface color to blending
between them using the subsurface parameter.
commit 482ec5d1f2
Author: Schoen <schoepas@deher1m1598.emea.adsint.biz>
Date: Mon Mar 13 15:47:12 2017 +0100
Fixed a bug that caused an additional white diffuse closure call when using
path tracing.
commit 26e906d162
Merge: 0593b8c223aff9
Author: Pascal Schoen <pascal_schoen@gmx.net>
Date: Mon Feb 6 11:32:31 2017 +0100
Merge branch 'master' into cycles_disney_brdf
commit 0593b8c51b
Author: Pascal Schoen <pascal_schoen@gmx.net>
Date: Mon Feb 6 11:30:36 2017 +0100
Fixed the broken GLSL shader and implemented the Disney BRDF in the
real-time view port.
commit 8c7e11423b
Author: Pascal Schoen <pascal_schoen@gmx.net>
Date: Fri Feb 3 14:24:05 2017 +0100
Fix to comply strict compiler flags and some code cleanup
commit 17724e9d2d
Merge: 379ba34520afa2
Author: Pascal Schoen <pascal_schoen@gmx.net>
Date: Tue Jan 24 09:59:58 2017 +0100
Merge branch 'master' into cycles_disney_brdf
commit 379ba346b0
Author: Pascal Schoen <pascal_schoen@gmx.net>
Date: Tue Jan 24 09:28:56 2017 +0100
Renamed the Disney BSDF to Principled BSDF.
commit f80dcb4f34
Author: Pascal Schoen <pascal_schoen@gmx.net>
Date: Fri Dec 2 13:55:12 2016 +0100
Removed reflection call when roughness is low because of artifacts.
commit 732db8a57f
Author: Pascal Schoen <pascal_schoen@gmx.net>
Date: Wed Nov 16 09:22:25 2016 +0100
Indication if to use fresnel is now handled via the type of the BSDF.
commit 0103659f5e
Author: Pascal Schoen <pascal_schoen@gmx.net>
Date: Fri Nov 11 13:04:11 2016 +0100
Fixed an error in the clearcoat where it appeared too bright for default
light sources (like directional lights)
commit 0aa68f5335
Author: Pascal Schoen <pascal_schoen@gmx.net>
Date: Mon Nov 7 12:04:38 2016 +0100
Resolved inconsistencies in using tabs and spaces
commit f5897a9494
Author: Pascal Schoen <pascal_schoen@gmx.net>
Date: Mon Nov 7 08:13:41 2016 +0100
Improved the clearcoat part by using GTR1 instead of GTR2
commit 3dfc240e61
Author: Pascal Schoen <pascal_schoen@gmx.net>
Date: Mon Oct 31 11:31:36 2016 +0100
Use reflection BSDF for glossy reflections when roughness is 0.0 to
reduce computational expense and some code cleanup
Code cleanup includes:
- Code style cleanup and removed unused code
- Consolidated code in the bsdf_microfacet_multi_impl.h to reduce
some computational expense
commit a2dd0c5faf
Author: Pascal Schoen <pascal_schoen@gmx.net>
Date: Wed Oct 26 08:51:10 2016 +0200
Fixed glossy reflections and refractions for low roughness values and
cleaned up the code.
For low roughness values, the reflections had some strange behavior.
commit 9817375912
Author: Pascal Schoen <pascal_schoen@gmx.net>
Date: Tue Oct 25 12:37:40 2016 +0200
Removed default values in setup functions and added extra functions for
GGX with fresnel.
commit bbc5d9d452
Author: Pascal Schoen <pascal_schoen@gmx.net>
Date: Tue Oct 25 11:09:36 2016 +0200
Switched from uniform to cosine hemisphere sampling for the diffuse and
the sheen part.
commit d52d8f2813
Author: Pascal Schoen <pascal_schoen@gmx.net>
Date: Mon Oct 24 16:17:13 2016 +0200
Removed the color parameters from the diffuse and sheen shader and use
them as closure weights instead.
commit 8f3d927385
Author: Pascal Schoen <pascal_schoen@gmx.net>
Date: Mon Oct 24 09:57:06 2016 +0200
Fixed the issue with artifacts when using anisotropy without linking the
tangent input to a tangent node.
commit d93f680db9
Author: Pascal Schoen <pascal_schoen@gmx.net>
Date: Mon Oct 24 09:14:51 2016 +0200
Added subsurface radius parameter to control the per color channel
effection radius of the subsurface scattering.
commit c708c3e53b
Author: Pascal Schoen <pascal_schoen@gmx.net>
Date: Mon Oct 24 08:14:10 2016 +0200
Rearranged the inputs of the shader.
commit dfbfff9c38
Author: Pascal Schoen <pascal_schoen@gmx.net>
Date: Fri Oct 21 09:27:05 2016 +0200
Put spaces in the parameter names of the shader node
commit e5a748ced1
Author: Pascal Schoen <pascal_schoen@gmx.net>
Date: Fri Oct 21 08:51:20 2016 +0200
Removed code that isn't in use anymore
commit 75992bebc1
Author: Pascal Schoen <pascal_schoen@gmx.net>
Date: Fri Oct 21 08:50:07 2016 +0200
Code style cleanup
commit 4dfcf455f7
Merge: 243a0e32cd6a89
Author: Pascal Schoen <pascal_schoen@gmx.net>
Date: Thu Oct 20 10:41:50 2016 +0200
Merge branch 'master' into cycles_disney_brdf
commit 243a0e3eb8
Author: Pascal Schoen <pascal_schoen@gmx.net>
Date: Thu Oct 20 10:01:45 2016 +0200
Switching between OSL and SVM is more consistant now when using Disney
BSDF.
There were some minor differences in the OSL implementation, e.g. the
refraction roughness was missing.
commit 2a5ac50922
Author: Pascal Schoen <pascal_schoen@gmx.net>
Date: Tue Sep 27 09:17:57 2016 +0200
Fixed a bug that caused transparency to be always white when using OSL and
selecting GGX as distribution of the Disney BSDF
commit e1fa862391
Merge: d0530a87f76f6f
Author: Pascal Schoen <pascal_schoen@gmx.net>
Date: Tue Sep 27 08:59:32 2016 +0200
Merge branch 'master' into cycles_disney_brdf
commit d0530a8af0
Author: Pascal Schoen <pascal_schoen@gmx.net>
Date: Tue Sep 27 08:53:18 2016 +0200
Cleanup the Disney BSDF implementation and removing unneeded files.
commit 3f4fc826bd
Author: Pascal Schoen <pascal_schoen@gmx.net>
Date: Tue Sep 27 08:36:07 2016 +0200
Unified the OSL implementation of the Disney clearcoat as a simple
microfacet shader like it was previously done in SVM
commit 4d3a0032ec
Author: Pascal Schoen <pascal_schoen@gmx.net>
Date: Mon Sep 26 12:35:36 2016 +0200
Enhanced performance for Disney materials without subsurface scattering
commit 3cd5eb56cf
Author: Pascal Schoen <pascal_schoen@gmx.net>
Date: Fri Sep 16 08:47:56 2016 +0200
Fixed a bug in the Disney BSDF that caused specular reflections to be too
bright and diffuse is now reacting to the roughness again
- A normalization for the fresnel was missing which caused the specular
reflections to become too bright for the single-scatter GGX
- The roughness value for the diffuse BSSRDF part has always been
overwritten and thus always 0
- Also the performance for refractive materials with roughness=0.0 has
been improved
commit 7cb37d7119
Author: Pascal Schoen <pascal_schoen@gmx.net>
Date: Thu Sep 8 12:24:43 2016 +0200
Added selection field to the Disney BSDF node for switching between
"Multiscatter GGX" and "GGX"
In the "GGX" mode there is an additional parameter for changing the
refraction roughness for materials with smooth surfaces and rough interns
(e.g. honey). With the "Multiscatter GGX" this effect can't be produced at
the moment and so here will be no separation of the two roughness values.
commit cdd29d06bb
Merge: 02c315ab40d1c1
Author: Pascal Schoen <pascal_schoen@gmx.net>
Date: Tue Sep 6 15:59:05 2016 +0200
Merge branch 'master' into cycles_disney_brdf
commit 02c315aeb0
Author: Pascal Schoen <pascal_schoen@gmx.net>
Date: Tue Sep 6 15:16:09 2016 +0200
Implemented the OSL part of the Disney shader
commit 5f880293ae
Merge: 630b80eb399a6d
Author: Pascal Schoen <pascal_schoen@gmx.net>
Date: Fri Sep 2 10:53:36 2016 +0200
Merge branch 'master' into cycles_disney_brdf
commit 630b80e08b
Author: Pascal Schoen <pascal_schoen@gmx.net>
Date: Fri Sep 2 10:52:13 2016 +0200
Fresnel in the microfacet multiscatter implementation improved
commit 0d9f4d7acb
Author: Pascal Schoen <pascal_schoen@gmx.net>
Date: Fri Aug 26 11:11:05 2016 +0200
Fixed refraction roughness problem (refractions were always 100% rough)
and set IOR of clearcoat to 1.5
commit 9eed34c7d9
Merge: ef29aaeae475e3
Author: Pascal Schoen <pascal_schoen@gmx.net>
Date: Tue Aug 16 15:22:32 2016 +0200
Merge branch 'master' into cycles_disney_brdf
commit ef29aaee1a
Author: Pascal Schoen <pascal_schoen@gmx.net>
Date: Tue Aug 16 15:17:12 2016 +0200
Implemented the fresnel in the multi-scatter GGX for the Disney BSDF
- The specular/metallic part uses the multi-scatter GGX
- The fresnel of the metallic part is controlled by the specular value
- The color of the reflection part when using transparency can be
controlled by the specularTint value
commit 88567af085
Merge: cc267e5285e082
Author: Pascal Schoen <pascal_schoen@gmx.net>
Date: Wed Aug 3 15:05:09 2016 +0200
Merge branch 'master' into cycles_disney_brdf
commit cc267e52f2
Author: Pascal Schoen <pascal_schoen@gmx.net>
Date: Wed Aug 3 15:00:25 2016 +0200
Implemented the Disney clearcoat as a variation of the microfacet bsdf,
removed the transparency roughness again and added an input for
anisotropic rotations
commit 81f6c06b1f
Merge: ece5a087065022
Author: Pascal Schoen <pascal_schoen@gmx.net>
Date: Wed Aug 3 11:42:02 2016 +0200
Merge branch 'master' into cycles_disney_brdf
commit ece5a08e0d
Author: Pascal Schoen <pascal_schoen@gmx.net>
Date: Tue Jul 26 16:29:21 2016 +0200
Base color now applied again to the refraction of transparent Disney
materials
commit e3aff6849e
Author: Pascal Schoen <pascal_schoen@gmx.net>
Date: Tue Jul 26 16:05:19 2016 +0200
Added subsurface color parameter to the Disney shader
commit b3ca6d8a2f
Author: Pascal Schoen <pascal_schoen@gmx.net>
Date: Tue Jul 26 12:30:25 2016 +0200
Improvement of the SSS in the Disney shader
* Now the bump normal is correctly used for the SSS.
* SSS in Disney uses the Disney diffuse shader
commit d68729300e
Author: Pascal Schoen <pascal_schoen@gmx.net>
Date: Tue Jul 26 12:23:13 2016 +0200
Better calculation of the Disney diffuse part
Now the values for NdotL und NdotV are clamped to 0.0f for a better look
when using normal maps
commit cb6e500b12
Author: Pascal Schoen <pascal_schoen@gmx.net>
Date: Mon Jul 25 16:26:42 2016 +0200
Now one can disable specular reflactions again by setting specular and
metallic to 0 (cracked this in the previous commit)
commit bfb9cb11b5
Author: Pascal Schoen <pascal_schoen@gmx.net>
Date: Mon Jul 25 16:11:07 2016 +0200
fixed the Disney SSS and cleaned the initialization of the Disney shaders
commit 642c0fdad1
Author: Pascal Schoen <pascal_schoen@gmx.net>
Date: Mon Jul 25 16:09:55 2016 +0200
fixed an error that was caused by the missing LABEL_REFLECT in the Disney
diffuse shader
commit c10b484dca
Author: Jens Verwiebe <info@jensverwiebe.de>
Date: Fri Jul 22 01:15:21 2016 +0200
Rollback attempt to fix sss crashing, it prevented crash by disabling sss completely, thus useless
commit 462bba3f97
Author: Jens Verwiebe <info@jensverwiebe.de>
Date: Thu Jul 21 23:11:59 2016 +0200
Add an undef for sc_next for safety
commit 32d348577d
Author: Jens Verwiebe <info@jensverwiebe.de>
Date: Thu Jul 21 00:15:48 2016 +0200
Attempt to fix Disney SSS
commit dbad91ca6d
Author: Pascal Schoen <pascal_schoen@gmx.net>
Date: Wed Jul 20 11:13:00 2016 +0200
Added a roughness parameter for refractions (for scattering of the rays
within an object)
With this, one can create a translucent material with a smooth surface and
with a milky look.
The final refraction roughness has to be calculated using the surface
roughness and the refraction roughness because those two are correlated
for refractions. If a ray hits a rough surface of a translucent material,
it is scattered while entering the surface. Then it is scattered further
within the object. The calculation I'm using is the following:
RefrRoughnessFinal = 1.0 - (1.0 - Roughness) * (1.0 - RefrRoughness)
commit 50ea5e3e34
Author: Pascal Schoen <pascal_schoen@gmx.net>
Date: Tue Jun 7 10:24:50 2016 +0200
Disney BSDF is now supporting CUDA
commit 10974cc826
Author: Pascal Schoen <pascal_schoen@gmx.net>
Date: Tue May 31 11:18:07 2016 +0200
Added parameters IOR and Transparency for refractions
With this, the Disney BRDF/BSSRDF is extended by the BTDF part.
commit 218202c090
Author: Pascal Schoen <pascal_schoen@gmx.net>
Date: Mon May 30 15:08:18 2016 +0200
Added an additional normal for the clearcoat
With this normal one can simulate a thin layer of clearcoat by applying a
smoother normal map than the original to this input
commit dd139ead7e
Author: Pascal Schoen <pascal_schoen@gmx.net>
Date: Mon May 30 12:40:56 2016 +0200
Switched to the improved subsurface scattering from Christensen and
Burley
commit 11160fa4e1
Author: Pascal Schoen <pascal_schoen@gmx.net>
Date: Mon May 30 10:16:30 2016 +0200
Added Disney Sheen shader as a preparation to get to a BSSRDF
commit cee4fe0cc9
Merge: 4f955d06b5bab6
Author: Pascal Schoen <pascal_schoen@gmx.net>
Date: Mon May 30 09:08:09 2016 +0200
Merge branch 'cycles_disney_brdf' of git.blender.org:blender into cycles_disney_brdf
Conflicts:
intern/cycles/kernel/closure/bsdf_disney_clearcoat.h
intern/cycles/kernel/closure/bsdf_disney_diffuse.h
intern/cycles/kernel/closure/bsdf_disney_specular.h
intern/cycles/kernel/closure/bsdf_util.h
intern/cycles/kernel/osl/CMakeLists.txt
intern/cycles/kernel/osl/bsdf_disney_clearcoat.cpp
intern/cycles/kernel/osl/bsdf_disney_diffuse.cpp
intern/cycles/kernel/osl/bsdf_disney_specular.cpp
intern/cycles/kernel/osl/osl_closures.h
intern/cycles/kernel/shaders/node_disney_bsdf.osl
intern/cycles/render/nodes.cpp
intern/cycles/render/nodes.h
commit 4f955d0523
Author: Pascal Schoen <pascal_schoen@gmx.net>
Date: Tue May 24 16:38:23 2016 +0200
SVM and OSL are both working for the simple version of the Disney BRDF
commit 1f5c41874b
Author: Pascal Schoen <pascal_schoen@gmx.net>
Date: Tue May 24 09:58:50 2016 +0200
Disney node can be used without SVM and started to cleanup the OSL implementation
There is still some wrong behavior for SVM for the Schlick Fresnel part at the
specular and clearcoat
commit d4b814e930
Author: Pascal Schoen <pascal_schoen@gmx.net>
Date: Wed May 18 10:22:29 2016 +0200
Switched from a parameter struct for Disney parameters to ShaderClosure params
commit b86a1f5ba5
Author: Pascal Schoen <pascal_schoen@gmx.net>
Date: Wed May 18 10:19:57 2016 +0200
Added additional variables for storing parameters in the ShaderClosure struct
commit 585b886236
Author: Pascal Schoen <pascal_schoen@gmx.net>
Date: Tue May 17 12:03:17 2016 +0200
added output parameter to the DisneyBsdfNode
That has been forgotten after removing the inheritance of BsdfNode
commit f91a286398
Author: Pascal Schoen <pascal_schoen@gmx.net>
Date: Tue May 17 10:40:48 2016 +0200
removed BsdfNode class inheritance for DisneyBsdfNode
That's due to a naming difference. The Disney BSDF uses the name 'Base Color'
while the BsdfNode had a 'Color' input. That caused a text message to be
printed while rendering.
commit 30da91c9c5
Author: Pascal Schoen <pascal_schoen@gmx.net>
Date: Wed May 4 16:08:10 2016 +0200
disney implementation cleaned
commit 30d41da0f0
Author: Pascal Schoen <pascal_schoen@gmx.net>
Date: Wed May 4 13:23:07 2016 +0200
added the disney brdf as a shader node
commit 1f099fce24
Author: Pascal Schoen <pascal_schoen@gmx.net>
Date: Tue May 3 16:54:49 2016 +0200
added clearcoat implementation
commit 00a1378b98
Author: Pascal Schoen <pascal_schoen@gmx.net>
Date: Fri Apr 29 22:56:49 2016 +0200
disney diffuse und specular implemented
commit 6baa7a7eb7
Author: Pascal Schoen <pascal_schoen@gmx.net>
Date: Mon Apr 18 15:21:32 2016 +0200
disney diffuse is working correctly
commit d8fa169bf3
Author: Pascal Schoen <pascal_schoen@gmx.net>
Date: Mon Apr 18 08:41:53 2016 +0200
added vessel for disney diffuse shader
commit 6b5bab6cec
Author: Pascal Schoen <pascal_schoen@gmx.net>
Date: Wed May 18 10:22:29 2016 +0200
Switched from a parameter struct for Disney parameters to ShaderClosure params
commit f6499c2676
Author: Pascal Schoen <pascal_schoen@gmx.net>
Date: Wed May 18 10:19:57 2016 +0200
Added additional variables for storing parameters in the ShaderClosure struct
commit 7100640b65
Author: Pascal Schoen <pascal_schoen@gmx.net>
Date: Tue May 17 12:03:17 2016 +0200
added output parameter to the DisneyBsdfNode
That has been forgotten after removing the inheritance of BsdfNode
commit 419ee54411
Author: Pascal Schoen <pascal_schoen@gmx.net>
Date: Tue May 17 10:40:48 2016 +0200
removed BsdfNode class inheritance for DisneyBsdfNode
That's due to a naming difference. The Disney BSDF uses the name 'Base Color'
while the BsdfNode had a 'Color' input. That caused a text message to be
printed while rendering.
commit 6006f91e87
Author: Pascal Schoen <pascal_schoen@gmx.net>
Date: Wed May 4 16:08:10 2016 +0200
disney implementation cleaned
commit 0ed0895914
Author: Pascal Schoen <pascal_schoen@gmx.net>
Date: Wed May 4 13:23:07 2016 +0200
added the disney brdf as a shader node
commit 0630b742d7
Author: Pascal Schoen <pascal_schoen@gmx.net>
Date: Tue May 3 16:54:49 2016 +0200
added clearcoat implementation
commit 9f3d39744b
Author: Pascal Schoen <pascal_schoen@gmx.net>
Date: Fri Apr 29 22:56:49 2016 +0200
disney diffuse und specular implemented
commit 9b26206376
Author: Pascal Schoen <pascal_schoen@gmx.net>
Date: Mon Apr 18 15:21:32 2016 +0200
disney diffuse is working correctly
commit 4711a3927d
Author: Pascal Schoen <pascal_schoen@gmx.net>
Date: Mon Apr 18 08:41:53 2016 +0200
added vessel for disney diffuse shader
Differential Revision: https://developer.blender.org/D2313
The idea is to make include statements more explicit and obvious where the
file is coming from, additionally reducing chance of wrong header being
picked up.
For example, it was not obvious whether bvh.h was refferring to builder
or traversal, whenter node.h is a generic graph node or a shader node
and cases like that.
Surely this might look obvious for the active developers, but after some
time of not touching the code it becomes less obvious where file is coming
from.
This was briefly mentioned in T50824 and seems @brecht is fine with such
explicitness, but need to agree with all active developers before committing
this.
Please note that this patch is lacking changes related on GPU/OpenCL
support. This will be solved if/when we all agree this is a good idea to move
forward.
Reviewers: brecht, lukasstockner97, maiself, nirved, dingto, juicyfruit, swerner
Reviewed By: lukasstockner97, maiself, nirved, dingto
Subscribers: brecht
Differential Revision: https://developer.blender.org/D2586
So now the following OSL versions are supported (at least for compilation):
- 1.5 with closure alignment patch applied
- 1.6.8 release
- 1.7 development version from latest git
This header was already included into some of the implementation files already,
and this change is needed for some upcoming changes in the way how kernel_types.h
works.
give a result more similar to the Compatible falloff option. The scale is x2
though to keep the perceived scatter radius roughly the same while changing the
sharpness. Difference with compatible will be mainly on non-flat geometry.
New features:
* Bump mapping now works with SSS
* Texture Blur factor for SSS, see the documentation for details:
http://wiki.blender.org/index.php/Doc:2.6/Manual/Render/Cycles/Nodes/Shaders#Subsurface_Scattering
Work in progress for feedback:
Initial implementation of the "BSSRDF Importance Sampling" paper, which uses
a different importance sampling method. It gives better quality results in
many ways, with the availability of both Cubic and Gaussian falloff functions,
but also tends to be more noisy when using the progressive integrator and does
not give great results with some geometry. It works quite well for the
non-progressive integrator and is often less noisy there.
This code may still change a lot, so unless you're testing it may be best to
stick to the Compatible falloff function.
Skin test render and file that takes advantage of the gaussian falloff:
http://www.pasteall.org/pic/show.php?id=57661http://www.pasteall.org/pic/show.php?id=57662http://www.pasteall.org/blend/23501
well as I would like, but it works, just add a subsurface scattering node and
you can use it like any other BSDF.
It is using fully raytraced sampling compatible with progressive rendering
and other more advanced rendering algorithms we might used in the future, and
it uses no extra memory so it's suitable for complex scenes.
Disadvantage is that it can be quite noisy and slow. Two limitations that will
be solved are that it does not work with bump mapping yet, and that the falloff
function used is a simple cubic function, it's not using the real BSSRDF
falloff function yet.
The node has a color input, along with a scattering radius for each RGB color
channel along with an overall scale factor for the radii.
There is also no GPU support yet, will test if I can get that working later.
Node Documentation:
http://wiki.blender.org/index.php/Doc:2.6/Manual/Render/Cycles/Nodes/Shaders#BSSRDF
Implementation notes:
http://wiki.blender.org/index.php/Dev:2.6/Source/Render/Cycles/Subsurface_Scattering
