A polygon does not mirror as it should, it merely copies it over, so I need to rotate it afterward)
When I want to edit the rotated (copy) of the polygon (model->edit ) it appears in its original rotation, which is quite confusing.
When you mirror in Capture it is not the model of individual objects that gets mirrored, but rather the placement or arrangement of all the objects you have selected. The main reason for this is that it is impossible to mirror fixtures as well as many truss items. The kind of mirroring you were expecting would be the one found in a 3D modelling tool where you are defining the shape of an object rather than placing objects.