Why is this happening. I’ve rebuilt the main volume as cleanly as possible and yet whenever I go to cut the input ports I get a confusing mess.
Hello- hard to say without the file.
-Pascal
Most of the time when I get this it is a meshing problem. As brep is rendered as mesh there is a bad meshing. Try to settle a better meshing quality in “Render Mesh Settings”
Typically when you have bad meshes like that, you have bad trims. I would not change the mesh settings to try and “fix” the problem, I would try to fix the object instead, then it should mesh correctly.
I would first explode the big box and use rebuild edges then rejoin. If it doesn’t rejoin into a closed box, you will find your out of tolerance edges. Also use DivideAlongCreases>SplitAtTangents=Yes on the big box to make sure the rounds are separate surfaces, the mesher doesn’t like internal G1 joints.
When all else fails, post the model… 
MacStudio.3dm (2.8 MB)
There’s some corruption I can’t find. When I make an edges copy of the face and extrude ‘closed planar curve’. I get this error.
I’d made two rectangles and aligned them then did some trimming after adding some diagonal lines to get the HDMI shape. Lookin closely it’s apparent what’s happened. Is there some command or best practice method of avoiding this sort of micro error?
