Creating Corners with Mirror / Symmetry Is there a modifier/tool or plugin to replicate the symmetry/mirror effects like the one at step 12 here:

https://knowledge.autodesk.com/support/3ds-max/getting-started/caas/CloudHelp/cloudhelp/2015/ENU/3DSMax-Tutorial/files/GUID-42DD88AC-4988-4CBB-A3FE-6298B1ECC9B3-htm.html

Basically all I want to do is create corner pieces of an existing modular model.
Thanks!
All I had to do was to check Bisect in the mirror modifier after rotating it 45° in Edit mode. Thanks anyways. Problem solved.