# How to quickly fix (or avoid) the n-gons caused by boolean operation?

I'm trying to model a pistol slide with grooves in it which is supposed to look like this:

What I did was creating an array of cubes and subtracting it from the slide with boolean modifier. This precedure ended up with multiple n-gons:

I thought those n-gons might cause some trouble later on, so I used the knife tool to manually cut all the faces into quads.

As there were only 7 grooves in the mesh, I didn't spend too much time doing this. But I wonder if there is a easier or better way to get the same result, in case the object is much more complex than the one I'm making.

If you were making a lot of these grooves, maybe it would be quicker to model them than to fix a Boolean ... something like this ...

Throughout the example, the pivot is set to 'Active Element', and Snap is set to 'Vertex' and 'Active'. This object is X along, Z up.

• Starting with your beveled cuboid
• Decide on the depth of the groove, CtrlR cut a loop in the base and, using an active vertex on it, GY snap it in Y to the corresponding bevel-profile edge. Select all the faces which will contain the grooves
• ShiftDMake a duplicate of the whole object (to keep your selection)
• On the duplicate, deselect all but three of the sections.

• In the duplicate, CtrlI Invert the selection, X delete all other faces, and EY extrude the central section in Y
• Select all the vertices on the front of the extrusion, and lastly, one of the ones on minimum Y, and SY0scale in Y to 0. select all, and CtrlVRRemove Doubles.
• X Delete faces appropriate to making a repeating unit.

• Assign an Array modifier to the unit, with merge switched on, with the right length to fill the grooved section, and select the edges you will want to dissolve later. Apply the array, and the edge selection is preserved, CtrlX Dissolve the selected edges in the arrayed grooves.

• X Delete the selected faces on the original ,and CtrlJ join the ridged section to it.
• Again , with all vertices of the ridged section selected, and an active vertex somewhere on its minimum Y, snap the ridged section back into the original mesh, and remove doubles.

• Thank you for your effort making this very detailed answer! This inspires me a lot. Dec 7, 2018 at 3:17
• BTW is it possible to make the grooves and gaps between them have different widths? For example let grooves be 3mm in width and gaps 2mm? Dec 7, 2018 at 3:32
• @sacrish Sure. Surrounding details permitting, instead of patching the grooves in, as in this answer, probably the quickest way would be to build the entire block from an array of in+out elements, where the in and out sections have different X-widths. I don't quite know why I didn't do that here. I think I was imagining surrounding pre-existing details, handles, etc, and trying not to interfere with transitions to them. Dec 7, 2018 at 6:46
1. Select the N-gons with Shift+G
2. CTRL+T
3. Alt+J

This is the fast and easy way. The minus is that it's not always all quads. And avoid Boolean if you can as corrections are required if you use it

OR, easier yet

Use CTRL+R once on the pointed edge and snap it to vertices before you OK it.

Btw. okaying answers gives you +2 reputation.

• UV for the attempted bribery in your answer :D Dec 6, 2018 at 14:43
• Sorry but I tried the easier way you suggested, and it seemed only to add one loop cut on that single face (probably because the face next to it was not a quad). Did I do something wrong? Dec 7, 2018 at 3:28