Shadow artifacts on double sided plane

Question

When I cast a light on a double sided plane, I see a glitchy artifact. Does anyone know why it is there and what I should do to avoid this problem? Thanks in advance!

I c

Answer 1

You are getting artifacts from self-shadowing. You have two options. One is to set

plane.receiveShadow = false;

The other is to set light.shadowBias.

light.shadowBias = -0.001;

Unfortunately, setting shadowBias can result in another artifact: "Peter Panning".

Google these topics if you want to know more about the issues.

Updated fiddle: http://jsfiddle.net/scjcvx3k/7/

three.js 71