LiveGraphics3D.pl file in pg/macros. The changes were made last May
in pull request https://github.com/openwebwork/pg/pull/211
and pull request https://github.com/openwebwork/webwork2/pull/587.
You can read further details there.
You don't need to change the problems themselves.
The safest way to upgrade the 3d graphics is still probably to upgrade to release/2.11