How to split a body with a curved surface

I have attached a file. In it is a curved surface placed where i want it. My goal is to intersect it in a way that it splits the body of the square into two separate objects, where they can be easily moved without it grabbing other geometry. made in 2021 but saved in 2019 format

splitting the body 2019.skp (567.5 KB)

Put the curved surface in the component and use Intersect Faces. Then copy the component to the clipboard, erase the unwanted geometry. Exit edit model, paste in place, open the pasted component for editing and erase the unwanted geometry in that. It’ll leave you with the two halves.

Done with keyboard shortcuts.

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hmmm, ok, probably the wrong order i did then.

so, make the curved surface a component, then intersect with the other compoent via rmc intersect model, then copy the curved surface component, and enter the square component, and paste in place, then remove geometry?


No! Put the curved surface inside the box component. Select it, cut it to the clipboard, open the box component for editing and paste in place.

Select the geometry and using Intersect Faces>With Selection.

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thats what i did the first time and it does put the curved surface face inside the box, i can see it when i turn on xray, but its not allowing me to move the top half of the box, it stays connected to the edges:)

my steps:

  1. selected the curved surface, and cut
  2. opened box comp
  3. paste in place
  4. select the geometry and intersect faces>selection

intersecting faces

After you intersect the curved surfaces with the rest of the box follow the rest of my steps. Exit component edit mode, copy the component to the clipboard. open the component for editing, delete the unwanted geometry leaving only the bottom of the box with the curved top. Exit edit mode, Paste in place, open the pasted component for editing and delete the bottom half of the box leaving the top with the curved surface. Just like I did in my GIF.

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I need to get on better wifi than the trains. Your gif is not there at the moment. Ill be to class in 5 minutes, then i can look.

Thanks for helping as usual:)

Ok, now that im off the train, and at campus, your gif shows up. I see now how its a multi process. I got half of it rihht, it was the second half. For some reason i thought it would split it forbme without the extra copy and paste step.

If i knew how to program, this would be a good extension haha.

Ill try to follow the steps and see what i get.


You can also select within the component context and make group/comp.
Split group
BTW, Dave’s version gives you the split face on both groups, mine you would need to copy it over or deal with it in some other way.

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Awesome. Thanks for this. I came very close to discovering this method before i posted. I juat never made the top piece a group haha. If i would have done that, i would have been closer, but then i would have never seen daves way of things.

I wonder if im at the.point where i could possibly answer questions on the forums now hahaha.

The right to left select and group is also a useful way to delete some things, it doesn’t leave a bunch of stray edges to manually cleanup.

A simple example.
Group delete

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I wonder why going fromnleft to right, even though only the top portion 2as select3d, that it deleted moat the box

Surely you know that right to left selects differently to left to right!?


Yes i do haha. Just in the gif, i couldnt see all the highlighted edges, only top portion was selected. I couldnt tell that it grabed the 4 primary edges.

I use right to left when making the mask i dis last week.

That’s like saying I remember the last time I breathed in.
The two versions of select should be something you use constantly, so much so you don’t even think about it. I know for me every time I need to write left to right I have to do it to check which one I mean.


Hahahaha, yeah, i dont use the two different select modes with the mouse to often. I usually do the solid line box selection, i think thats left to right. I dont use the dashed line box select all to often