How to symmetrize object in angle? Here what I'm trying to achieve:


In 3ds max it can be done by rotating mirror plane of symmetry modifier. Video

In blender we can do almost the same with mirror modifier and rotating "mirror object", but the main difference is lack of slicing. Part of the mesh that cross mirror plane is not removed automatically.

So how we can do symmetry with rotation similar to 3ds max in blender?
You could probably achieve this with a combination of two modifiers.

You can use any object type as a mirror object, set up a mesh as object as mirror center, and use it also in a Boolean modifier.

Model it in the shape of a 'half box' so that it is a volume bounding only the half of the object you want to remove, then use it also as mirror axis.