Hello,
it’s probably pretty easy. but I can’t get any further.
I have one Cylinder and one Cube (with bevel). I made a boolean operation to cut out the cube from the cylinder.
You can see the shading issue in the screenshot. do i have to add additonal geometry? i tried “harden normals” and “weighted normals”.
The problem is cause by the Boolean giving you very thin trianglar faces. The best way to mitigate this is to add additional edge loops around your cylindrical mesh that ‘bracket’ where the curved edge of the boolean box cuts into it. That should make the new faces smaller and more even.
After a quick test myself, the results inprove by adding more length-wise edges to you cylinder. The exact number and position will depend on your specific geometry.
However there is another way that is best demonstrated by Chipp Walters in this video, which involves copying the normals data from a clean pre-boolean mesh to the post boolean mesh
Thank you both. unfortunately I didn’t have time to test it again.
can someone explain to me why this shading problem occurs. ok, too little geometry, but I still haven’t understood the principle behind it
It’s caused by the thin triangles ( created by the Boolean ) trying to smooth shade. If you switch the mesh to flat shading you’ll see that there is no issue, but obviously that isn’t what you want. Using a higher side-count cylinder [ 64 ] and more supporting loops at the boolean intersection will mitigate these.
To see these thin triangles, collapse the boolean modifier so you are down to a mesh, then in edit mode:
As you can see in my example those thin triangles are revealed [ this is a 16 sided cylinder - too low ]. If you really want a clean surface for this you would need to go in and clean up the topology once you have the shape necessary, and that is going to involve adding additional loops anyway. Even the top example might need some tweaking.
