A physical mirror is a reflective surface, a reflector.
Often the reflector, (mirror), is a flat piece of glass coated with silver or aluminum.
In MoI the planar mirror is accomplished with math. The virtual object is the new mirrored object

Operation of the Mirror command:
1. Select objects to mirror.
2. Pick start point.
3. Pick a (different) end point.

In MoI Top View:
The start point is on the plane of the reflector, and establishes a rotation center.
The end point, with (x and/or y) different from the start point, is also on the plane of the reflector, and determines the angle of the reflector.
The z values of the two points could be different.
Any z value different from the start point z value determines a plane of reflection.
Moving the end point changes the ANGLE of the reflector.
The z value of any point P on the object is the same as its mirror.
The new x and y value of any point P are determined by the ANGLE.

In MoI Front View:
The x and z values of the end point determine the ANGLE of the reflector.

In MoI Right View:
The y and z values of the end point determine the ANGLE of the reflector.

In MoI 3D View:
The x, y, and z values together can change the 3D angle.
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Suggestion for another method to perform a mirror.

1. Select objects to mirror.
2. Select the reflector plane, the plane of reflection.
3. Select a point to establish a normal to the reflector plane.
If the point is on the reflector, calculate the normal of the reflector plane, (flipped)?
If the point is not on the reflector, perform drop point to the reflector surface, and find the normal. The point on the reflector surface corresponds to Start Point. Calculate the point corresponding to the End Point. Feed the Mirror factory...
- Brian