Differential D4205 Diff 13203 manual/render/eevee/shadows.rst

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manual/render/eevee/shadows.rst

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	Select the shadow map type. It changes how shadows are stored and filtered.	Select the shadow map type. It changes how shadows are stored and filtered.

	:abbr:`ESM (Exponential Shadow Mapping)`	:abbr:`ESM (Exponential Shadow Mapping)`
	They are fast to filter but suffer form light leaking near the occluder.	These are fast to filter but suffer form light leaking near the occluder.
	This can be minimized by increasing the Exponent parameter.	This can be minimized by increasing the Exponent parameter.
	Another issue is the artifacts present at depth discontinuity.	Another issue is the artifacts present at depth discontinuity.
	Unfortunately, there is no workaround for this issue and the only way	Unfortunately, there is no workaround for this issue and the only way
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	It is also prone to light leaking when two occluders overlap.	It is also prone to light leaking when two occluders overlap.
	In this case the shadows can be overdarkened to reduce the leak,	In this case the shadows can be overdarkened to reduce the leak,
	by using the Bleed Bias parameter.	by using the Bleed Bias parameter.
	VSM uses twice as much memory as ESM, and are slower.	VSM uses twice as much memory as ESM and is slower.

	Cube Size	Cube Size
	Size of the shadow cubemaps used to shadow Point, Area and Spot lights.	Size of the shadow cubemaps used to shadow Point, Area and Spot lights.
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	High Bitdepth	High Bitdepth
	This option can help reduce some artifacts due to float imprecision inside the shadow maps.	This option can help reduce some artifacts due to float imprecision inside the shadow maps.
	This option effectively double the memory usage of shadow maps and will slow down their update.	It effectively doubles the memory usage by shadow maps and will slow down their update.

	Soft Shadows	Soft Shadows
	Randomize the shadow maps origin to create soft shadows. It needs a lot of samples to get rid of the banding.	Randomizes the shadow maps origin to create soft shadows.
		This needs a lot of samples to reduce banding.

	Light Threshold	Light Threshold
	In order to avoid costly setup time, this distance is first computed	In order to avoid costly setup time, this distance is first computed
	automatically based on a light threshold. The distance is computed	automatically based on a light threshold. The distance is computed
	at the light origin and using the inverse square falloff. The setting	at the light origin and uses inverse square falloff. The setting
	can be found inside the :menuselection:`Render Settings panel --> Shadow tab`.	can be found inside the :menuselection:`Render Settings panel --> Shadow tab`.

	This light threshold does not take the light shape into account and may not	Light threshold does not take the light shape into account and may not
	suit every case. That is why we provide a per-lamp override where you can	suit every case. That is why we provide a per-lamp override where you can
	just set the cut off distance	just set the cut off distance
	(:menuselection:`Light Properties Panel --> Light --> Custom Distance`).	(:menuselection:`Light Properties Panel --> Light --> Custom 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 concerns sun lights that still have a far clip distance.	This influence distance does not concerns sun lights, which still have a far clip distance.

	.. seealso::	.. seealso::

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	.. tip::	.. tip::

	A 512px cubemap is 6 x 512 x 512 pixels in it.	A 512 px cubemap has 6 x 512 x 512 pixels in it.
	Tweaking the Size parameters can have a big impact on memory consumption and performance.	Tweaking the Size parameters can have a big impact on memory consumption and performance.


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	Soft	Soft
	Size of the filter applied to the shadow map.	Size of the filter applied to the shadow map.
	This filter size is independent from the shadow map resolution.	This filter size is independent of the shadow map resolution.
	Higher filter size can have a big impact on performance.	Higher filter size can have a big impact on performance.
	There is a maximum cap to filter size (in pixels) that depends on shadow resolution.	There is a maximum cap to filter size (in pixels) that depends on shadow resolution.

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	Contact Shadows	Contact Shadows
	---------------	---------------

	This type of shadows exists to fix light leaking caused by Bias or shadow map undersampling.	This type of shadow exists to fix light leaking caused by bias or shadow map undersampling.
	They uses the depth buffer to find occluders (just like Screen Space Reflections).	It uses the depth buffer to find occluders (just like Screen Space Reflections).
	However, exactly like Screen Space Reflections, they suffer from the same limitations:	However, just like Screen Space Reflections it suffers from the same limitations,
	unknown object thickness, effect disappearing at screen edges.	namely, unknown object thickness and effect disappearing at screen edges.

	.. tip::	.. tip::

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	World space distance in which to search for screen space occluder.	World space distance in which to search for screen space occluder.

	Softness	Softness
	Control how soft the contact shadows will be. Contact shadow blurring does not match light's physical size.	Controls how soft the contact shadows will be.
		Contact shadow blurring does not match a light's physical size.

	Bias	Bias
	Bias applied to the ray tracing to reduce self shadowing artifacts.	Bias applied to the ray tracing to reduce self-shadowing artifacts.

	Thickness	Thickness
	Pixel thickness used to detect occlusion. Treat any potential occluder to be this thick.	Pixel thickness used to detect occlusion, treating any potential occluder as this thick.


	.. _eevee-cascaded-shadow-map:	.. _eevee-cascaded-shadow-map:
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	Cascaded Shadow Map	Cascaded Shadow Map
	-------------------	-------------------

	These special kind of shadow maps are used by Sun lights.	This special kind of shadow map is used by Sun lights.
	This is because they can shadow large scenes by distributing multiple shadow maps over the frustum range.	It can shadow large scenes by distributing multiple shadow maps over the frustum range.
	Each cascade covers a different portion of the view frustum.	Each cascade covers a different portion of the view frustum.
	Do note that cascade shadow map are always updated because they are view dependent.	Note that cascade shadow maps are always updated because they are view dependent.
	This means they have a high performance impact.	This means they have a high performance impact.

	Count	Count
	Number of cascade to use. More cascade means better precision but slower update.	Number of cascades to use. More cascades means better precision but slower updates.

	Fade	Fade
	Fade transition area between two cascades.	Fade transition area between two cascades.
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	Higher values means less overall resolution because cascades need to overlap.	Higher values means less overall resolution because cascades need to overlap.

	Max Distance	Max Distance
	Distance away from the view origin (or camera origin if in camera view) to cover with the cascade.	Distance away from the view origin (or camera origin if in camera view) to cover by the cascade.
	If the view far clip distance is lower than Max Distance, the lowest of the two will be used.	If the view far clip distance is lower than Max Distance, the lowest of the two will be used.
	Only works in perspective view.	Only works in perspective view.

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	- Shadows are not supported on light instances (dupli objects, group instancing).	- Shadows are not supported on light instances (dupli objects, group instancing).
	- Only 128 active lights can be supported by Eevee in a scene.	- Only 128 active lights can be supported by Eevee in a scene.
	- Only 8 Shadowed sun lights can be supported at the same time.	- Only 8 Shadowed sun lights can be supported at the same time.

		Shadow Catcher
		==============

		.. tip::

		Until Eevee has a built-in shadow catcher like Cycles a good shadow catching technique can be found at:
		`Blender Artists <https://blenderartists.org/t/cycles-ground-for-hdri-environment-aka-shadow-light-catcher/636320>`__ -- for Cycles, but works for Eevee too.
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