September 10, 2012, 11:13:13 am
As arch_bd said, it is not yet possible to achieve perfect planar reflections for mirrors etc in Lumion.
Reflections in Lumion rely on a single 360 degree panoramic reflection texture which is projected onto all reflective materials, such as the window on your screenshot.
This 360 degree panoramic reflection texture is rendered high above the scene by default.
If you want to change the position of this 360 degree panoramic reflection texture, you will have to add the Reflection Control object to your scene (Lights -> Utilities -> Reflection Control). This lets you specify the position where the 360 degree panoramic reflection texture should be rendered at.
However, even if you move the Reflection Control object around, just bear in mind that you will still not be able to achive perfect reflections. The closest you get is an approximation.
TIP: In some situations, the best position for the Reflection Control object is at the camera position.