# Join 2 faces with different shapes together

I want to join the bottom part of that octagon in the plane below it (both are selected in the image). I also want to keep the size of both of them, I just want to insert the octagon in the plane, with the same X, Y coordinate and the Z coordinate of the plane.

Thanks.

• Drop the bottom face of the octagon down to the same z location as the plane.
• Then delete the faces on the plane and bottom of the octagon.

You can then select the edges of the bottom of the octagon, as well as the edges of the plane, and F to create a face (which would be an n-gon)...

• Then with the face you just created selected, press Ctrl-Fto bring up the face menu and select "triangulate faces"...

This will result in triangle faces connecting the outer edge of the octagon to the inner edge of the plane.

If you are not happy with triangular faces, you can select the faces in question and use Ctrl-F > Tris to quads

Edit: you may have to join the objects first by selecting both, pressing spacebar, and searching for "join"

EDIT 2: Upon testing my explanation, it didn't work for me as intended... i will leave it there for posterity but ill post the way i did it that DID work.

1: extend the bottom face of the octagon down JUST BELOW the face of the secondary mesh

2: ensure that only the octagon is selected and add a boolean modifier to it [Properties Window > Modifiers > Boolean]

3: Set the "Operation" to "Union" and the "Object" to the mesh in question.

4: Apply the modifier

• note that the boolean modifier will create a copy of the "Object" you selected and work with that, so you may need to delete the unmodified mesh that is left behind from the modifier...

good luck, and sorry if my first answer didn't work =(

• The first way worked. I was so stupid trying to find out a Blender function to do that, and it was so simple. Thanks. – Pacha Mar 27 '14 at 22:03