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Contact shadows

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    Contact shadows


    I've been going through quite a few posts that touch the subject but not seen any straight answer to my question.

    How does Contact shadows work, like the one in the attached image. It feels like there is no "easy" path but can they be achieved with all kind of light sources? Is it even dependent on the source itself or do i have to activate something in the settings?


    Basically it's a screen-space effect that traces rays from a light source to the pixel being processed (er, I think that may be the reverse, but it's close enough for an explanation). You generally keep the contact shadow value limited to [0.0,1.0]; the the higher the value, the more artifacts you'll receive. I generally keep mine at something like 0.1 or 0.2.

    Though, reading the documentation, it refers only to point lights; I actually have mine on a directional light, so things may be a bit different.
    This page provides an overview of Contact Shadows in UE4.
    Trent Polack (@mittense)
    Personal Site | Development Blog | Joy Machine


      The contact shadows feature is for dynamic lighting--the issue with dynamic lighting is that the shadow bias setting can make objects appear to float above objects they're supposed to be on top of, so the contact shadows make it more accurate. With baked static lighting, getting the shadows to line up better depends on how high resolution your lightmaps are--low resolution won't be as accurate.


        Is this feature supported for mobile?