Previously, the "Simplify" option was a world space distance threshold. This meant that zooming in and out of the view changed the way this option behaved. There were complaints from artists about this. This change improves two things: * The simplify algorithm uses the screen space coordinates rather than the 3D positions. * The UI setting is in pixels making it much easier to tweak (no need for values in the 1e-4 range). Pull Request: https://projects.blender.org/blender/blender/pulls/122719