wow, I just did an L and a cross -shaped building and each time I SEO the walls (target) to the roof (operator) using Subtraction with upwards extrusion, all the inside corner wall disappeared
Same results, inside corner walls disappear when subtracting with downward extrusion.
Playing around with this in AC13 the eave edge was showing as custom even though I had set the roof eave to perpendicular . When I set the eaves to perpendicular and then SEO, it works as it should.
Similar in 14 but here the roof eave showed correctly perpendicular and 90° but until I toggled the eave to another edge type and back to perpendicular it would not SEO correctly.
Erika
Architect, Consultant
MacBook Pro Retina, 15-inch Yosemite 2.8 GHz Intel Core i7 16 GB 1600 MHz DDR3
Mac OSX 10.11.1
AC5-18
Onuma System
"Implementing Successful Building Information Modeling"