Create Light Volume (From Faces)

What you must prepare first

• Blender must be in Object Mode.
• You must have exactly two mesh objects selected.
• Each selected mesh must have exactly one selected quad face.

If any of those conditions is not met, the operator stops and returns a warning instead of creating a broken volume.

Why selection order matters

The addon reads the two selected mesh objects in a strict A → B order. The first selected object defines the source side of the volume (A), and the second selected object defines the target side (B). In Blender, that second selected object is typically also the active object.

This is important because the generated prism, the locked fade direction, and the spread logic are all built around that A → B construction. In practical terms, you should select the object that represents the light source first (for example a window), then select the object that represents the destination area second (for example the floor).

What happens when you click the button

The addon reads the two selected quad faces in world space, reorders face B to best match face A, then generates a prism between them. The created object receives a dedicated material configured in Light Volume mode, and the new object becomes the active selection.

Expected geometry behavior

If face A and face B do not match perfectly, the generated prism may differ slightly from the original B face. This is expected. The addon prioritizes planar faces in the generated prism to avoid twisted or deformed faces that could produce unstable or ugly volumetric results. Face B is therefore adjusted as little as possible while keeping the generated volume usable and clean.

What changes after creation

Fade Direction is locked on From Faces objects because the object already has a built-in A → B direction. That control is therefore hidden in the panel. Invert Fade remains available, so the user can still reverse the internal fade without rebuilding the object.