Problem with Boolean modifier


I tried to “cut” a cylinder shape out of a mesh via the Boolean modifier.
This worked fine, the shape was realy cut out well, but when I used smooth on the mesh, I got the dark area’s around the edge where it was cut.
I noticed that there were some triangles at those areas and tried to remove them (alt-J) but that didnt solve it. I also did <ctrl-n> for recalculating the normals but that didn’t do it either.

What can I do to get rid of these dark area’s. Is there another option to get rid of the triangles automatically or do I have to add edge loops manually?

Or maybe there’s another way to cut the cylinder out of this mesh?




check out if all the veticies are merge together
some seems to be not at the same level than the other !

try to mark the edges and use the edgsplit also

and let us know what happen



Thanks for your reply!!
I tried edgesplit modifier and that did it!
Have to check later what this modifier really does but for now this is perfect!




The edge split modifier changes the way that Set Smooth smooths the mesh. Every angle under 30 degrees (by default) will be smoothed. But sharper angles, like 31 and above, will not be smooth. When you get sharp angles like 90+ degrees smoothing looks really bad, but the edge split modifier will skip those parts and smooth other ones making it look overall better.

what happen to the mark sharp edges

is this taken into consideration or ot when applying the edgsplit modifier?



Thanks for your explanation!
By the way, love your Wall-e model!

Looking at Henske screenshot I have to re-think my opinion on booleans: it seems to do a good job in this model.

in 2.48a the boolean was improve and seems tom work much better
but still it does not work with all shapes and forms of object

but it has been improbed and it’s much better than the old version


I typically avoid using Boolean operations as the result is unpredictable. In this case I would have created my basic cylindrical box, carefully adopting topology to the final result; then retopoed a rescaled circle on top of it; and finally rebuilt my mesh from there. Might sound complicated, but doesn’t take that long with some experience.

/ Mats