Problem with intersect faces command ( level: beginner )

I have a problem when i use the intersect face command. I’m a beginner when it comes to sketchup so the solution could be a easy one.

when i try to intersect two cylindrical shapes i lose certain faces and some unexplainable faces appear.

In general, whenever two edges cross and you force SketchUp to create new edges where they cross, there might be new edges that are too small. Then endpoints will merge.
See the image where new red edges (like in your situation) may be to short: they’ll vanish and you may even loose faces there.

Lower the number of segments of the smaller cilinder to better match the larger cilinder.

Working at a larger scale will work too but as soon as you scale down again to the actual size the same problems will arise: Endpoints will merge.

Edit: the left red edge shouldn’t be a problem to SketchUp. It’s even larger than the corresponding top edge of the cilinder facet. But the right ones are definitely shorter.

1 Like

Thanks, problem solved!