Trying to intersect two tunnels I'm trying to create sewer tunnels for game development and I cant seem to figure out how to make an intersection.

We've tried boolean but it doesnt seem to want to work properly nor cutting... Does anyone have any suggestions?
There are several ways to do it, here is one:

Create your tunnel section, create an empty close to it, give your tunnel a Mirror modifier with the empty as Mirror Object, enable Axis, Bisect and Flip on the right axis (here X):




Rotate your empty 45° on the Z axis and move it so that the tunnel and its mirrored version cross each other:



Apply the modifier, go in Edit mode, select all, in the header menu &gt; Mesh &gt; Symmetrize, and in the Operator box choose the right axis:




Symmetrize in the other axis: