Why does my EASE model have a negative room volume?
A negative volume means that your room is "inside-out", which might result from the fact most or all faces or your model have the wrong orientation.
EASE distinguishes between the acoustically effective side (thick grey frame) and the exterior side (no frame) of a face.
All acoustically active sides (thick grey frame) must be orientated facing in the room.
To change all faces of your room, go to SURFACES > ORIENTATION > INVERT ALL FACES. Your room volume now is positive and turns green.
If only some faces are wrongly orientated, select all those faces and navigate to SURFACES > ORIENTATION > INVERT FACE. Multiple faces can be selected by drawing a frame over those faces with the left mouse button or selecting faces by clicking the left mouse button + CTRL.