Intersection to delete portion of a Group

I have an item that is a Group. I place it in my model and it intersects another item in the model. I tried Intersect With Model and selecting the portion I don’t want so I can delete it, but the whole Group that I inserted gets deleted.

Another way to look at what I am trying to do is think of a horizontal line segment and a vertical line segment. If you place them on top of each other the form a “+”. I want to cut the part of above the horizontal line segment resulting in a “T”.

How about uploading the model so we can see what you’ve got.

It sounds like you need to do something you aren’t. Maybe exploding the group before running the intersection. If you intersect a group with something else in the model, the geometry inside the group won’t be modified because it is protected in the group “container”. If you want the geometry of the group to be modified you need to either get rid of the group container by exploding or you need to open the group for editing and then use Intersect. The latter will put the intersection inside the group, though, and it won’t modify the rest of the model.

rafter.skp (108.5 KB)

Intersect Faces with … creates its edges in the current drawing context.
If you apply the operation on both groups you get edges outside both groups.
Hence groups themselves won’t be affected.
You’ll need to open the blue group for editing and (selecting its context) apply the same operation … to intersect with model. The new edges will now appear inside the blue group.

Thanks, I new I was doing something wrong with the “Intersect with …” !

I haven’t touched SketchUp in over a year and even then I was only an Advanced Beginner !

Well, that worked, mostly ! It left a couple of vertical lines on two of the face of purple item. Those are still part of the Group. When I select the Group for editing, I can not delete them.rafter.skp (105.6 KB)

You can’t delete them with the purple group open because they are not in that group. Most of them are loose in the model. There is also a stray edge left in the blue group. Seems like you weren’t careful enough cleaning things up after the intersection.

The purple item is not a Group. The lines are part of the blue item, which is a Group, but even when I edit the group and draw lines around where the blue touches the purple I can not delete those line.

I tried editing the blue Group again and drawing a line completely around where it touched the purple face, exited the Group edit and I COULD delete the lines !

Oh well !

OK, it’s a component. Not an important difference in this situation.

purple

No, they are loose in the model, not within either the purple or the blue object. The bounds of the blue object stick up because it has a stray edge at the other side.

edges

These loose edges outside the group are probably the remainders of your earlier intersect operation outside groups. You don’t see them but they are created.