[Bf-docboard-svn] bf-manual: [7792] trunk/blender_docs/manual/render/eevee: EEVEE: Update Depth Of Field documentation

[Clément Foucault]

Revision: 7792
          https://developer.blender.org/rBM7792
Author:   fclem
Date:     2021-03-02 11:58:16 +0100 (Tue, 02 Mar 2021)
Log Message:
-----------
EEVEE: Update Depth Of Field documentation

Modified Paths:
--------------
    trunk/blender_docs/manual/render/eevee/limitations.rst
    trunk/blender_docs/manual/render/eevee/render_settings/depth_of_field.rst

Modified: trunk/blender_docs/manual/render/eevee/limitations.rst
===================================================================
--- trunk/blender_docs/manual/render/eevee/limitations.rst	2021-02-26 01:14:10 UTC (rev 7791)
+++ trunk/blender_docs/manual/render/eevee/limitations.rst	2021-03-02 10:58:16 UTC (rev 7792)
@@ -66,9 +66,8 @@
 Depth of Field
 ==============
 
-- Rendered at half resolution which can create blocky pixel artifacts on tiny features that are nearly in focus.
-- The near and far defocus buffers are in fact one single continuous texture. This can make some bleeding
-  appear on the left and right sides of the image. This can be fixed by using the *overscan* feature.
+- Alpha blended surfaces cannot be correctly handled by the post-processing blur, but will be correctly handled by the
+  sample based method. For this, you need to disable the post-process depth of field by setting the *Max Size* to 0.
 
 
 Screen Space Effects

Modified: trunk/blender_docs/manual/render/eevee/render_settings/depth_of_field.rst
===================================================================
--- trunk/blender_docs/manual/render/eevee/render_settings/depth_of_field.rst	2021-02-26 01:14:10 UTC (rev 7791)
+++ trunk/blender_docs/manual/render/eevee/render_settings/depth_of_field.rst	2021-03-02 10:58:16 UTC (rev 7792)
@@ -4,17 +4,27 @@
 Depth of Field
 **************
 
-Depth of field is done as a post-process effect in Eevee.
-The depth of field effect can be controlled in the :doc:`camera settings </render/cameras>`.
+To render a scene, EEVEE uses a pinhole camera model which produces a perfectly focused image of the scene.
+To improve realism, EEVEE can simulate the optical :term:`Depth of Field` using a post-process filter, and a sample based method.
+The optical settings can be controlled in the :doc:`camera settings </render/cameras>`.
+The quality of the effect can be controlled using the settings found in the present section.
 
 .. note::
 
    In the 3D Viewport, depth of field only works while in Camera View.
 
-.. note::
+The post-process method is computed in two passes.
+The first pass is using a blur that fails to produce quality bokeh for highlights but works for the general case.
+The second pass is sprite based and is reserved for very bright highlights to improve their quality.
+However is too slow to use for every part of the image.
+So it is only applied to very bright parts of the image that are different from their surroundings.
+The *Sprite Threshold* and *Neighbor Rejection* parameters control which pixels are being processed by second pass.
 
-   Because of performance considerations, the viewport can exhibit color artifacts when using large bokeh sizes.
-   These artifacts are not present in the final render.
+The sample based method works by randomizing the camera position for every sample.
+It is more accurate but needs many samples to achieve smooth results.
+The post-process blurring radius is scaled down accordingly to remove under-sampling.
+However, some scenes might still need more post-process blur in order to remove the noticeable sample pattern.
+This is exactly what the *Overblur* option does, but it will also reduce the bokeh shape sharpness.
 
 .. admonition:: Reference
    :class: refbox
@@ -22,6 +32,47 @@
    :Panel:     :menuselection:`Render --> Depth of Field`
 
 Max Size
-   Max size of the bokeh shape for the depth of field (lower is faster).
+   Maximum size in pixels of the depth of field post-process effect (lower is faster).
+   A value of 0 will disable the post-process effect but not the sample based method.
 
+Sprite threshold
+   Minimum brightness a pixel needs to have to be considered by the sprite based depth of field.
+   Higher values will improve performance but will reduce highlight quality.
+   Brightness is in scene referred color-space.
+
+Neighbor Rejection
+   Maximum intensity to consider when doing sprite neighborhood rejection.
+   This should be set to a brightness value above which there is little visual differences to be noticeable after color management.
+   Lower values will improve performance but will reduce highlight quality.
+   Brightness is in scene referred color-space.
+
+Denoise Amount
+   This will reduce the flickering by clamping the color of each pixels to their neighborhood's average instead of their maximum.
+   Higher values gives more stable results but may darken the scene.
+
+High Quality Slight Defocus
+   Increase the quality of almost in-focus regions.
+
+Jitter Camera
+   Randomize the camera position for every scene render sample to increase precision.
+   Enabling this option can change the scene's actual sample count.
+
+   .. note::
+
+      Be aware that the actual sample count can grow quite rapidly.
+
+   .. hint::
+
+      The actual number of samples is computed by the following formula:
+
+      .. math::
+
+         sample\_count = (ring\_count^{2} + ring\_count) * 3 + 1
+
+      where :math:`ring\_count` is the number of ring in the hexaweb pattern.
+      The :math:`ring\_count` is chosen so that the entire pattern contains at least the number of samples set in :doc:`render settings </render/sampling>`.
+
+Overblur
+   Scales the post process depth of field radius to reduce artifacts. Higher values will soften the bokeh shape.
+
 .. seealso:: :ref:`Limitations <eevee-limitations-dof>`.