[Bf-docboard-svn] bf-manual: [9163] trunk/blender_docs/manual: Document MNEE caustics

[Alaska]

Revision: 9163
          https://developer.blender.org/rBM9163
Author:   Alaska
Date:     2022-04-02 23:44:47 +0200 (Sat, 02 Apr 2022)
Log Message:
-----------
Document MNEE caustics

Modified Paths:
--------------
    trunk/blender_docs/manual/render/cycles/gpu_rendering.rst
    trunk/blender_docs/manual/render/cycles/light_settings.rst
    trunk/blender_docs/manual/render/cycles/object_settings/object_data.rst

Added Paths:
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    trunk/blender_docs/manual/images/render_cycles_object-settings_caustics-example1.png
    trunk/blender_docs/manual/images/render_cycles_object-settings_caustics-example2.png

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Index: trunk/blender_docs/manual/images/render_cycles_object-settings_caustics-example1.png
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--- trunk/blender_docs/manual/images/render_cycles_object-settings_caustics-example1.png	2022-04-02 07:45:23 UTC (rev 9162)
+++ trunk/blender_docs/manual/images/render_cycles_object-settings_caustics-example1.png	2022-04-02 21:44:47 UTC (rev 9163)

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--- trunk/blender_docs/manual/images/render_cycles_object-settings_caustics-example2.png	2022-04-02 07:45:23 UTC (rev 9162)
+++ trunk/blender_docs/manual/images/render_cycles_object-settings_caustics-example2.png	2022-04-02 21:44:47 UTC (rev 9163)

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Modified: trunk/blender_docs/manual/render/cycles/gpu_rendering.rst
===================================================================
--- trunk/blender_docs/manual/render/cycles/gpu_rendering.rst	2022-04-02 07:45:23 UTC (rev 9162)
+++ trunk/blender_docs/manual/render/cycles/gpu_rendering.rst	2022-04-02 21:44:47 UTC (rev 9163)
@@ -69,7 +69,9 @@
 Metal is supported on Apple computers with Apple Silicon or AMD graphics cards. macOS 12.2 is required to use Metal
 with Apple Silicon while macOS 12.3 is required to use Metal with AMD graphics cards.
 
+.. note:: :ref:`MNEE caustics <bpy.types.CyclesObjectSettings.is_caustics_caster>` are not supported in Metal.
 
+
 Frequently Asked Questions
 ==========================
 

Modified: trunk/blender_docs/manual/render/cycles/light_settings.rst
===================================================================
--- trunk/blender_docs/manual/render/cycles/light_settings.rst	2022-04-02 07:45:23 UTC (rev 9162)
+++ trunk/blender_docs/manual/render/cycles/light_settings.rst	2022-04-02 21:44:47 UTC (rev 9163)
@@ -22,18 +22,33 @@
 Cycles
 ======
 
+.. _bpy.types.CyclesObjectSettings.is_caustics_caster:
+
 Max Bounces
    Maximum number of times light from the light is allowed to :term:`Bounce <Light Bounces>`.
    Limited by :ref:`scene-wide bounce settings <bpy.types.CyclesRenderSettings.max_bounces>`.
+
+.. _bpy.types.CyclesObjectSettings.is_caustics_caster:
+
 Cast Shadow
    By disabling this option, light from lights will not be blocked by objects in between.
    This can speed up rendering by not having to trace rays to the light source.
+
+.. _bpy.types.CyclesObjectSettings.is_caustics_caster:
+
 Multiple Importance Sample
    By default lights use only direct light sampling. For area lights and sharp glossy reflections, however,
    this can be noisy,
    and enabling this option will enable indirect light sampling to be used in addition to reduce noise.
 
+.. _bpy.types.CyclesObjectSettings.is_caustics_light:
 
+Shadow Caustics
+   Mark a light to be a refractive caustic caster. This setting can be used in conjunction with the
+   :ref:`Cast and Receive caustics object settings <bpy.types.CyclesObjectSettings.is_caustics_caster>`
+   to selectively speed up refractive caustic rendering of select objects.
+
+
 Area Lights
 ===========
 

Modified: trunk/blender_docs/manual/render/cycles/object_settings/object_data.rst
===================================================================
--- trunk/blender_docs/manual/render/cycles/object_settings/object_data.rst	2022-04-02 07:45:23 UTC (rev 9162)
+++ trunk/blender_docs/manual/render/cycles/object_settings/object_data.rst	2022-04-02 21:44:47 UTC (rev 9163)
@@ -184,3 +184,48 @@
 AO Distance
    Override for the world's :ref:`AO Distance <bpy.types.CyclesRenderSettings.use_fast_gi>`,
    if the value is zero the world's distance is used.
+
+
+Caustics
+--------
+
+Mark objects as caustic casters or receivers. This is used in conjunction with a light with
+:ref:`Shadow Caustics <bpy.types.CyclesObjectSettings.is_caustics_light>` enabled to selectively
+speed up caustic rendering of objects in your scene. 
+
+.. note:: 
+
+   The rendering technique used to speed up the rendering of caustics is based on
+   :abbr:`MNEE (Manifold Next Event Estimation)`. There are a number of limitations with this technique
+   and it's implementation in Cycles:   
+
+   - Only refractive caustics in the shadows of objects work. Caustics from reflections or caustics that
+     fall outside shadows are not rendered with this technique.
+
+   - MNEE Caustics are not supported when the microfacet distribution is set to *Multiscatter GGX*.
+
+   - Caustics render best with objects with smooth normals.
+
+   - Bump and normal maps are ignored.
+
+   - The Metal GPU rendering backend is not supported.
+
+.. _bpy.types.CyclesObjectSettings.is_caustics_caster:
+
+Cast Shadow Caustics
+   Mark an object as a caustic caster.
+
+.. _bpy.types.CyclesObjectSettings.is_caustics_receiver:
+
+Receive Shadow Caustics
+   Mark an object as a caustic receiver.
+
+.. list-table::
+
+   * - .. figure:: /images/render_cycles_object-settings_caustics-example1.png
+
+          Rendering caustics inside an eye without MNEE at 32 samples per pixel.
+
+     - .. figure:: /images/render_cycles_object-settings_caustics-example2.png
+
+          Rendering caustics inside an eye using MNEE at 32 samples per pixel.