Trouble with Intersect Faces


A simple project where I’m try to cut a piece of pipe in half and it won’t let me, would you please tell me what I’m doing wrong.

2 components, select both, right click and choose IF with selection, explode both components and it only works on part of the pipe.test.skp (42.2 KB)


I found I had to select the inner and outer circle lines and do an Explode Curve. Then the intersect faces worked ok.


The problem with your technique is that Intersect Faces with always creates Edges only in the currently active edit context. In your case, that was the model as a whole, so the new Edges did not actually cut any Faces inside either of the Components. When you explode, that is not enough to cause those Edges to cut the Faces.

What you need to do is to get all the geometry into a single context before you do the intersection. For example, open the plane for edit, select the face, copy or cut it, then close that component. Next open the pipe component, do edit->paste in place to deposit a copy of the plane, and then do the intersection. Now, since the new edges are in the same context as the pipe’s geometry the faces will be cut.


Thanks Colin, that worked but was pretty tedious. I’ll try @slbaumgartner suggestion might be easier.


It only worked partially, the front and back faces of the pipe did not get cut, so I tried exploding the curves and it still didn’t work.

Tried it again and it worked perfectly! Most have done something wrong the first time.


Although you already got it, here’s an animation for the next person who might want a way to do this. No need to explode curves with this method.

  1. Explode the component with the rectangle. It doesn’t want to be a component.
  2. Select the rectangle and cut it to the clipboard. Ctrl-X, Command+X, etc.
  3. Open the pipe component for editing.
  4. Edit>Paste in place. I have a keyboard shortcut for that.
  5. The pasted rectangle will be selected. Hold Ctrl and triple click on the pipe to add all of its geometry to the selection.
  6. Right click and choose Intersect Faces>With Selection.
  7. Erase/delete the unwanted bits.
  8. Correct the face orientation as needed.


Thanks Dave, even better than @slbaumgartner solution, less clicks.


Just to be clear, it is the same basic idea just with a variation on how you get all the geometry into the same context before doing the intersect!