# Cutting an object out of a few others

Hey, I’m having trouble with Boolean-Difference.

I’m designing a “fort” of sorts, has segments cut out at angle so that it can fold together. It will look a lot like a die-line.
I have made the basic shape of the fort (after some trouble… turns out you cannot make a surface from more than 4 points), and now I am trying to cut out the angled slices on the overall shape. Boolean - Difference is not working for me, it isn’t removing that angled shape from the other shapes.

Attached FortWallsnRoof.3dm (2.6 MB)

Thanks.

Hi Kevin - to make a planar surface from multiple points, try `Polyline` (make sure it’s closed and planar, then `PlanarSrf` from that or `ExtrudeCurve > Solid=Yes.` Make your cutters a little oversized as well in this case to avoid coincident faces and edges. However, you’re V-shapes are cutting right to the bottom of the object - that means you have zero thickness there and a non-manifold edge, which should be avoided. Make your cutters not quite the full depth of the object you’re cutting.

FortWallsnRoof_PG.3dm (100.5 KB)

-Pascal

Whoa pascal! Thanks for the awesome response.

Can you explain why it won’t cut into the object and make it into two objects?

Thanks.

Hi Kevin - if the point of the cutter, so to speak, is right on the bottom surface the extruded object, there’s no clear separation between sides - the edges there are all coincident. I suppose it should or may be possible to sort things into multiple polysurfaces but that is not currently possible, or at least not done, and the input object is kept ‘whole’. If your cutter extends a little deeper, so there is a clear separation - even only a few thousandths (depending on the file tolerance) it will split it up.

https://mcneel.myjetbrains.com/youtrack/issue/RH-39807

-Pascal