Small miters form when you place 90º elbows on sloped pipes and then route pipe from the end of the elbow instead of letting Smart 3D create elbows based on the angle between the pipes.
Sloped piping typically needs trimmable elbows. If there are no trimmable elbows in the Catalog, Smart 3D cannot adjust the angle for sloped piping.
Use the following procedure to remove these small miter fittings:
Select the miter fitting.
The angle for the small miter fitting displays in the Angle 1 box.
Type 0 in the Angle 1 box.
Smart 3D removes the miter and adjusts the angle and orientation of the fitting to accommodate the sloped piping.