Real-time shadows doesn't connect to geometry.

Unity Engine
1

I created a simple test scene to demonstrate the issue. It contains: A plane, a cube, and a point light. In this screenshot I’ve positioned the light mostly overhead, but just a bit off to the side of the cube. Note that the shadow doesn’t actually connect to the front corner of the cube. The cube is flush with the plane, but the shadow effect gives it the impression that the cube is slightly off the ground.

2900354--213500--upload_2016-12-28_13-57-26.png
2900354--213500--upload_2016-12-28_13-57-26.png925×932 128 KB

If I bake the lighting instead, the shadows connect properly as I’d expect.

I’ve tried adjusting the bias on the light, but it just doesn’t get close enough. Is this a known issue with dynamic lighting? Or is there something I can do to ensure that the lighting actually connects to the corner?

If I drag my light way off to the size, the shadow no longer connects to the cube at all:

2900354--213501--upload_2016-12-28_14-1-30.png
2900354--213501--upload_2016-12-28_14-1-30.png963×513 122 KB

Thanks.

-Dan

2

Play a bit with the Bias settings, other than that, there isn’t much you can do.

3

Thanks. I’d already pushed all of the biases to the extremes in the screenshots I posted, but no luck.

I did notice this only seems to be an issue with Point lights, though. If I change the light to a Spot or Directional light, the shadow is much more accurate. Perhaps things will work better in Unity 5.6, with their lighting overhaul…

4

It happens in all engines and won’t be fixed - https://forums.unrealengine.com/showthread.php?59630-Dynamic-Lighting-Shadow-Bias-problems

5

Sonic Ether’s new screen space shadows would fix the issue tho, you may want to try those.