Using MakeHole to cut holes in an open surface?

I have a surface with single curvature, created by lofting two curves. I need to cut multiple holes in it, so I used “Squish” , created a hole pattern on the squished surface, and projected the holes onto the original surface with “Squishback”. I then tried to use “MakeHole” to cut all the holes in one go ( the help file says: “The MakeHole command projects selected closed curves to a surface or polysurface to define hole shapes.”), but I am getting extrusions of the hole instead. These extrusions are joined with the surface, and can be isolated by exploding which is what I eventually did to remove them.
I tried to “Pull” the hole pattern to the surface to see if that would make it easier, but it didn’t.
I tried using trim, but that is very tedious when you have a lot of holes, since you have to select the surface for each one of them. And for some of the holes I could not get the hole trimmed, Rhino insisted in trimming the remaining surface instead.
It looks like the MakeHole command is not working properly on open surfaces. I noticed that when it has been called, it asks to select a planar closed curve, but no mention of that has been made in the help file. But even a planar curve on a planar surface gives the same result.

My Rhino file:Holetest.3dm (2.5 MB)

A picture of the result. Note that the circle next to it will not work at all, even though it is a closed curve, Rhino considers it “invalid” for the MakeHole command:

Max.

Hi Max - use Split for this, I would say. Try:

Select the surface
Start Split
Select the curves or SelCrv
Enter
Cmd-Click the surface to de-select it.
Hit Delete to delete the split out holes.

-Pascal

1 Like

Thank you, Pascal. That is an efficient way of cutting holes. But my first try did not succeed for all the curves, only after "Pull"ing them to the surface it worked for all curves. It seems that the Squish-Squishback method does not generate the curves exactly on the surface.
And I would like to mention again that the “MakeHole”-command is not working properly on an open surface (version 5.2.1.).
Max.

Hi Max - MakeHole is working as designed - it is really a solid operation that only really makes sense if there is another face to hit behind the front face to connect that new hole surface. That said, it is on ‘the pile’, at least unofficially, to make it work like a trim operation when an open object is the target. I’ll make sure that is actually on the bug tracker.
http://mcneel.myjetbrains.com/youtrack/issue/RH-34945
-Pascal

OK, but at least the help file text needs to be more specific.
Max.

@margaret can the help be more specific here?

Sure. I’ll make a bugtrack item for it. http://mcneel.myjetbrains.com/youtrack/issue/RH-34948