Shadows¶
Eevee uses Shadow Mapping techniques to properly shadow the light coming directly from light objects.
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.
Reference
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- Method
Select the shadow map type. It changes how shadows are stored and filtered.
- ESM
- They are fast to filter but light leaking may occur near an occluder. This can be minimized by increasing the Exponent parameter. Another issue is the artifacts present at depth discontinuity. Unfortunately, there is no workaround for this issue and the only way to minimize it is to reduce the Soft parameter.
- VSM
- Filters nicely and gives smooth shadow map appearance across the whole shadow range. However grainy artifacts will be visible when using a low bit depth. It is also prone to light leaking when two occluders overlap. In this case the shadows can be overdarkened to reduce the leak, by using the Bleed Bias parameter. VSM uses twice as much memory as ESM, and is slower.
- 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.
- Cascade Size
- Size of one cascade used by Cascaded Shadow Maps. This is only for Sun lights.
- High Bitdepth
- 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.
- Soft Shadows
- Randomize the shadow maps origin to create soft shadows. It needs a lot of samples to get rid of the banding.
- Light Threshold
In order to avoid costly setup time, 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. The setting can be found inside the .
This light threshold does not take the light shape into account and may not suit every case. That is why we provide a per-light override 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. This influence distance does not concern sun lights that still have a far clip distance.
参考
注釈
The Soft Shadows method is not physically based and will not match Cycles for very large lights.
ちなみに
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.