How to intersect separate forms?

I have a cylinder meeting an oval and want to create an opening in the oval where they meet.

Select the surface of the oval, right click on it, choose Intersect Faces>With Model. Then erase the unwanted surface.

If these are solid objects you could also use Trim from the Solid Tools. I just did that to create a hole in the side of a thick tube. I used BoolTools 2, an extension that works in a similar way to the native Solid Tools but respects the “component-ness” of components.


Another example.
bool

If you share your .skp file so we can see exactly what you are trying to accomplish we could give you better, more precise instruction.

The oval is part of a group, do I ungroup before I try and delete the part of the surface to create a hole? Not working as part of the group.
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230903_Ornette Memorial_Glass Base in ground plane.skp (4.1 MB)

You need to open the group that is getting the hole so you can select the surface. Double click on the group with the Select tool or right click on it and chose Edit Group. Then right click on the face and choose Intersect Faces>With Model. Best to make sure the oval is passing through the surface, not just sitting on it.

Does that mean edit group?

Yes. Edit Group.

You’ve got some weird stuff in that group.

Excess geometry floating above the surface.

And weird hidden lines that aren’t needed.

After cleaning that stuff up, here’s Intersect Faces. I did also extrude the elliptical ring downward through the surface. That could be undone after the intersection is created.
intersect

I would suggest leaving out the materials until your geometry is all modeled correctly.

I meant to say see scene 104. The back of the cylinder has a line at the back that is 2" from the top of the cylinder. The cylinder needs to be moved down so that point intersects with the angled oval. I had done this and the cylinder outline in the oval is the result. This is the hole in the oval I need but also want the resultant sloped outline on the bottom of the cylinder in the exploded image 104.

note the oval has that sloped bottom a colleague had assisted with, but cant get it to work now so asking here for the cylinder.

Hope this is making sense

Just seeing your in depth response, trying now and thanks

Except you didn’t open that oval thing for editing so the edges created during the Intersect step are outside of the group. If you want the geometry to affect the surface in the oval, you need to open the oval group for editing.

If you clean up the messy geometry so the two objects are solid groups, you can use Trim from the Solid Tools to cut the opening. It would be a better choice in this case.
trim

So I need to make both objects solid before I intersect them, then intersect them?

If you want to use the Solid Tools for that, yes.

Not sure how to make a group into a solid

In order to be considered a solid in Sketchup, every edge in the group must be shared by exactly two faces. So no strray edges, no holes in surfaces, and no internal faces. You could get the Solid Inspector 2 extension from the 3D Warehouse to help you identify what needs fixing to make them solids. In many cases the tool can actually fix the bad geometry for you.

It’s a good idea to shoot for creating solid groups and components as you work. They will be the cleanest and easiest to work with.

OK I see I need to clean up the geometry, got it

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