I’ve been wondering why Unity never went for Variance Shadow Maps instead of PCF. I’m not exactly an expert on this topic, but everything I’ve read suggests that the shadow quality is way better, even with smaller shadow map resolutions.
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Hi,
Variance shadow map and others like exponential shadow map, have pros / cons like any algorithm.
They are good at allowing large kernel filter (i.e blurring for soft shadow), but there is a lot of light leaking that it hard to fix - in particular it depends on the distance between objects which is hard to control in a dynamic world.
For a generic engine like Unity, it make sense to stay with PCF fitlering as it have less instability, i.e it is easier to predict the result. So the choice isn’t about the quality, but more about the ease of setup and predictability.
Still HDRP pipeline use exponential shadow map for area light shadow as it is a good compromise of performance / quality in this context (large blur kernel can’t be achieve with PCF), and we accept the light leaking there
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