Contact Shadows in Unreal

In real-time interactive content like video games, objects often seem to be floating.

As objects come in contact to the ground, they seem to “not touch” or float above the ground.

So why does this matter?  If you were trying to achieve realism this is an instant reality-breaker that we are hard-wired to spot in an instant. If you see the feet of a chair not attached to the ground, it's an immediate queue saying  “what you see is not real”. 

On the other hand, however if this small shadow is present, our eyes are fooled into believing that the object is actually here.

This effect is especially pronounced when in VR goggles. You truly believe the chair is actually in front of you, it’s quite staggering.

So here are three ways to deal with this issue.

• Static GI
  • Bake Lightmass
  • Bake GPU lightmass
  • AO texture Baking
• Dynamic GI 
  • Distance field AO
  • Ambient Occlusion
  • Raytracing
• Hybrid 
  • Vertex Baked AO
  • 3DSmax
  • AO baker