The scene : a simple cube with the front face deleted, and a simple light behind the cube. The light could be seen inside the cube. It comes through the edges ! How to prevent this ? Thanks a lot ! Emmanuel
Yes, there are a couple of ways to handle these problems in EEVEE.
Thicker geometry reduces the problem:
Increasing the Shadow Exponent value on the spotlight makes the fade shorter.
Adding contact shadows fills in the fade:
It should however be noted that Contact Shadows are created with the depth map and may create undesired artefacts. This could be handled in a single shot but if you render a sequence it might be harder.
The VSM shadows (In render settings) generates a bit noisier shadow gradient but should be hided with less geometry.
Or if you absolutely need to keep your geometry paper thin you could add a tiny contact shadow.