Overhangs, bridging and supports that come off

Two separate problems that get muddled together: plastic sagging over air, and supports welding themselves to your part.

The 45° rule

Up to about 45° from vertical, each layer has enough of the one below to sit on. Past 50°, you need cooling, slower speed, or supports. Re-orienting the part is almost always better than adding supports.

Support settings worth changing

• Z gap 0.2mm — one layer height. Zero gap welds them on permanently
• Tree supports — less material, snap off cleanly, kinder to curves
• Touching build plate only — stops supports growing out of the model surface
• Accept that support-touching faces will be rougher, and hide them

Bridging

A flat span between two points prints fine unsupported up to about 50mm if cooling is at maximum and bridge speed is set properly. Test it before you fill the part with supports you do not need.