You can edit individual facets of any support region, whether it was created automatically or manually. Use the Add to Region  tool or the Remove from Region  tool followed by the green check box   to add or remove triangles from any existing support region. If one or more supports are already associated with that region, however, they will remain intact even after the support region has been edited. You need to create a new support after the change of the region and delete the old support.

Known Issues and Limitations

There is a known issue at this release in that adding and/or removing triangular facets to manual support regions does not work as expected. The workaround is to first generate an automatic support region on the surface where you want manual support regions. Then delete the automatically created support region and create manual support regions for that surface as described. This time, you will be able to add/remove individual triangular facets to the manual regions.