Question 1

How is the overhang angle calculated?

Accepted Answer

For every triangle we take the angle between its plane and the vertical: 0° is a vertical wall (no overhang), 90° is a horizontal ceiling (maximum overhang). A face counts as overhanging when this angle is above the threshold. Cura's “Support Overhang Angle” is measured the same way (0° = supports everywhere, 90° = nowhere), so values carry over one to one. In PrusaSlicer, Bambu Studio and OrcaSlicer the “Threshold angle” is measured from horizontal: supports are generated under faces whose slope from horizontal is below the threshold — so their value is 90° minus ours (our 30° is 60° there). The two only coincide at 45°.

Question 2

What threshold should I use?

Accepted Answer

45° is a common starting point for PLA and PETG: by the 45° rule, overhangs up to about 45° from vertical usually print without supports. For more droopy materials or critical parts, a lower threshold (35-40°) is often used to flag more potentially problematic areas. To match your slicer, use the note above the result: in Cura it is the same number, in PrusaSlicer/Bambu Studio/OrcaSlicer it is 90° minus our threshold.

Question 3

Does highlighting guarantee supports are needed?

Accepted Answer

No, it's an angle-based estimate — actual support need also depends on the overhanging span's length, cooling, print speed and your specific slicer settings. A test print or layer preview in your slicer is the final word.

Question 4

Does the file get uploaded anywhere?

Accepted Answer

No, everything is processed locally in your browser.

Overhang Checker

FAQ