RE: Shadow Findings

This post is more for newbie modelers.

I’ve been playing with a simple “box house” with a peaked roof and have made some interesting findings about shadows that confirms much of what has been recently discovered at Beamdog and Ossian about why shadow artifacts occur.

  1. Using a fully rendered (e.g. no faces deleted) cube with the top polygon slit into two polygons and raised to a peak, all shadows rendered correctly.

  2. Removing the bottom faces of the cube, which would not be visible, resulted in shadow anamolies.

  3. Using a more complex structure, simulating how a house would be constructed, all shadows rendered correctly. The house consisted of four “wall” cubes, a “floor” cube, and two “roof” cubes.

  4. When I removed faces from the cubes that would not be visible, numerous shadow artifacts occurred.

While this may be a bit premature given my limited testing, I have come to the conclusion that nearly all shadow anomalies can be fixed by not eliminating hidden faces from objects.

Cutouts for windows and doorways in walls should have faces that properly “frame” the cutout. Recessed features such as the inverted boxes used for doorways do not need to render shadows - such cutouts should use a “shadowplane” (a flat vertical plane with Render 0, Shadow 1) aligned with the wall so that the building’s shadow appears correctly.