[Bf-docboard-svn] bf-manual: [8834] trunk/blender_docs/manual/render/eevee: Updates to Eevee shadows to make it easier to read
Aaron Carlisle
noreply at blender.org
Thu Jan 20 19:42:04 CET 2022
Revision: 8834
https://developer.blender.org/rBM8834
Author: Blendify
Date: 2022-01-20 19:42:04 +0100 (Thu, 20 Jan 2022)
Log Message:
-----------
Updates to Eevee shadows to make it easier to read
Author: @mocsa
Differential Revision: https://developer.blender.org/D13860
Modified Paths:
--------------
trunk/blender_docs/manual/render/eevee/lighting.rst
trunk/blender_docs/manual/render/eevee/render_settings/shadows.rst
Modified: trunk/blender_docs/manual/render/eevee/lighting.rst
===================================================================
--- trunk/blender_docs/manual/render/eevee/lighting.rst 2022-01-20 18:11:43 UTC (rev 8833)
+++ trunk/blender_docs/manual/render/eevee/lighting.rst 2022-01-20 18:42:04 UTC (rev 8834)
@@ -26,10 +26,11 @@
=====
Specular
- Specular Light intensity multiplier. Use it for more artistic control.
- Setting this to anything but 1.0 will yield non-photorealistic result.
+ Specular Light intensity multiplier. Use it for artistic control.
+ Defines the intensity with which the light object will be visible in reflections on the surface of specular objects, like metals or mirrors.
+ Setting this to 0 will make the light object disappear from specular reflections. Keep it exactly at 1.0 for photorealistic results.
Custom Distance
- If enabled uses *Distance* as the custom attenuation distance instead of global light threshold.
+ If enabled, uses *Distance* as the custom attenuation distance instead of global Light Threshold.
In order to avoid long setup times, this distance is first computed
automatically based on a light threshold. The distance is computed
at the light origin and using the inverse square falloff.
@@ -39,7 +40,7 @@
.. seealso::
- :doc:`Light Threshold </render/eevee/render_settings/shadows>`.
+ Global :doc:`Light Threshold </render/eevee/render_settings/shadows>`.
.. note::
@@ -56,11 +57,14 @@
Clip Start
Distance from the light object at which the shadow map starts.
- Any object before this distance will not appear to cast shadows.
- *Clip Start* will only appear for point, spot and area lights.
+ Any object which is closer to the light than Clip Start will not cast shadows.
+ *Clip Start* is only available for point, spot and area lights.
Bias
- Bias applied to the depth test to reduce self shadowing artifacts.
+ Bias applied to the depth test to reduce self-shadowing artifacts.
+ This determines, what size of surface details (for example, bumps) will cast shadows on the object itself.
+ If this value is low, small bumps will cast shadows on the object's surface.
+ This might cause jagged shadow edge between the sunny and shadowy side of the object, but it can be smoothed out by turning on :doc:`Soft Shadows </render/eevee/render_settings/shadows>`
Contact Shadows
@@ -91,10 +95,11 @@
Cascaded Shadow Map
-------------------
-These special kind of shadow maps are used by Sun lights.
-This is because they can shadow large scenes by distributing multiple shadow maps over the frustum range.
-Each cascade covers a different portion of the view frustum.
-Do note that cascade shadow maps are always updated because they are view dependent.
+Sun lights usually illuminate a large scene with many objects, some close, some far away.
+To optimize shadow calculation in this situation, a technique called Cascaded Shadow Maps is used.
+The distance between the camera's near clip and far clip point is divided into as many equal intervals (called cascades) as you set the Count parameter below.
+For each cascade a different resolution shadow will be displayed: higher resolution for closer cascades and lower resolution for distant ones.
+Do note that cascade shadow maps are always updated because they depend on the camera position or your view origin in the 3D-Viewport.
This means they have a high performance impact.
.. note::
@@ -103,14 +108,16 @@
with an evenly distributed shadow precision.
Count
- Number of cascades to use. More cascades means better precision but a lower update rate.
+ Number of cascades to use. More cascades means better shadow precision but a lower update rate.
Fade
- Fade transition area between two cascades.
- Higher values means less overall resolution because cascades need to overlap.
+ When the Fade is greater than 0, the size of each cascade (distance interval) is increased so that neighboring cascades overlap.
+ Then a fade is applied in the overlapping region to provide a smooth transition between cascades.
+ Higher values mean the cascade's size is increased more, which decreases the available shadow resolution
+ inside the cascade since some of it is used in the overlapping region.
Max Distance
- Distance away from the view origin (or camera origin if in camera view) to cover by the cascade.
+ Distance away from the view origin (or camera origin if in camera view) to cover by the cascades.
If the view far clip distance is lower than Max Distance, the view far clip distance will be used.
Only works in perspective view.
Modified: trunk/blender_docs/manual/render/eevee/render_settings/shadows.rst
===================================================================
--- trunk/blender_docs/manual/render/eevee/render_settings/shadows.rst 2022-01-20 18:11:43 UTC (rev 8833)
+++ trunk/blender_docs/manual/render/eevee/render_settings/shadows.rst 2022-01-20 18:42:04 UTC (rev 8834)
@@ -4,18 +4,27 @@
Shadows
*******
-Eevee uses Shadow Mapping techniques to properly shadow the light coming directly from light objects.
+These settings influence shadows which appear on objects because there is another object (the occluder) between them and a Light.
+Eevee uses a technique called Shadow Mapping to calculate these shadows.
+A shadow map is calculated by looking around from the position of each Light and finding the objects which are closest to the Light.
+These objects are called the nearest occluders.
+Everything which is behind (or, you can say, covered by) the nearest occluders will be in shadow.
-A shadow map is a texture that stores the nearest occluder from the light position.
-Eevee also filters the shadow maps in order to smooth out the pixelated appearance.
+The shadow map is a cube (hence the term "cubemap") and the Light is in the middle of this cube. The cube has six sides and each side is divided into a grid. You can set the resolution of the grid (for example, 512 × 512 pixels) with the *Cube Size* setting below. During shadow calculation, the nearest occluders are only searched at grid points but not between grid points. Because of this, the edge of the calculated shadow will appear pixelated at low Cube Size settings.
+.. note::
+
+ Settings for the shadows and illumination caused by light bouncing between objects (indirect lighting) can be found on the Indirect Lighting tab.
+
+
.. reference::
:Panel: :menuselection:`Render --> Shadows`
Cube Size
- Size of the shadow cubemaps used to shadow Point, Area and Spot lights.
- Higher shadow map size will give higher precision and sharper shadows.
+ Number of pixels on one side of the shadow cubemap (see above) used to calculate the shadow of Point, Area and Spot lights.
+ If you want to make the edge of shadows less pixelated, then increase this value.
+ But be aware that this increases memory usage and decreases performance since a 512 px cubemap has 6 × 512 × 512 pixels in it.
Cascade Size
Size of one cascade used by *Cascaded Shadow Maps*. This is only for Sun lights.
@@ -25,7 +34,7 @@
This option effectively doubles the memory usage of shadow maps and will slow down their update.
Soft Shadows
- Randomize the shadow maps origin to create soft shadows. It needs a lot of samples to get rid of the banding.
+ Randomize the shadow map's origin to create soft shadows. It needs a lot of samples to get rid of the banding.
Light Threshold
The minimum amount of light for a light to contribute for lighting.
@@ -33,18 +42,14 @@
That is why Blender provides a :ref:`per-light override <bpy.types.Light.cutoff_distance>`
where you can just set the cut off distance.
- The influence distance is also used as shadow far clip distance, which might affect how shadows looks.
+ The influence distance is also used as shadow far clip distance, which might affect how shadows look.
This influence distance does not affect sun lights that still have a far clip distance.
.. seealso::
- :doc:`Custom Limit </render/eevee/lighting>`.
+ :ref:`Custom Distance <bpy.types.Light.cutoff_distance>`.
.. note::
The Soft Shadows method is not physically based and will not match Cycles for very large lights.
-.. tip::
-
- A 512 px cubemap has 6 × 512 × 512 pixels in it.
- Tweaking the *Size* parameters can have a big impact on memory consumption and performance.
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