blender · HeyBraza shows you
blender weird shading after boolean
HeyBraza points at the cleanup steps and the auto-smooth angle so the shading around your cut goes flat again.
booleans leave long n-gons and stray vertices behind, and smooth shading spreads that mess into dark smears across nearby faces. the fix is cleanup plus giving the cut some supporting geometry.
or do it yourself
- 1apply the boolean first (modifier dropdown > 'apply') - you can't clean geometry that only exists as a modifier preview.
- 2in edit mode select all (a) and press m > 'merge by distance' to remove the doubled vertices the cut left behind.
- 3with everything still selected press shift + n to recalculate normals outside.
- 4add supporting loops around the cut with ctrl + r so the smooth shading has somewhere to end - long thin n-gons are what smear.
- 5in object mode use 'object' > 'shade auto smooth' and lower the angle (about 30 degrees) so only genuinely round edges get smoothed.
let HeyBraza do this with you
HeyBraza is a tiny on-screen guide that points at the right buttons and talks you through it, on windows and mac.
downloadcommon questions
why does it look fine flat-shaded?
flat shading doesn't interpolate across faces, so it hides bad topology. auto smooth with a lower angle is the middle ground.
do i need to triangulate after a boolean?
not usually in blender, but a 'triangulate' modifier before export stops game engines from re-tessellating n-gons badly.