To have a customizable intensity, it would be better to add a light power option in the room modification panel like lights.

Here's what it gives in a derived version.


To add this feature, I modified 4 source files (RoomPanel.java, RoomController.java, Room.java and PhotoRenderer.java).
The main constraint is that for each update of Sweet Home 3D it will be necessary to create a corresponding derived version (SH3D-version_derived.jar).