How to compute dimensions of solar masks

[iaselle]

Hi everybody,

I've been browsing this forum for a couple of days but since I'm a dummy about 3D geometry, here is a new thread !

According to attached image, I have to write a piece of code that will detect, for a dedicated wall, if other faces can cast shadows to it : adjacents wall with re-entrant angles or adjacent horizontal faces like overhangs.

The variables the code has to compute (imposed by an external program) are the following :

• distR and deptR (see figure) for a reentrant wall located on the right of the wall
• distL and deptL for a reentrant wall located on the left of the wall
• distT and deptT (see figure) for a overhang that is on the top of the wall

My questions are :

• how to detect reentrant wall since the "angle_between" function does not work as expected (see post alternative to angle_between?)
• how to know when an adjacent face is "on the right" or "on the left" of the current face (viewed from outside)
• how to compute the "left", "right" and "top" distances between a window (componentinstance) and the edges of a wall ?

Thank you very much in advance

PS : here are some posts that might be helping
alternative to angle_between? http://www.sketchucation.com/forums/viewtopic.php?f=180&t=19300
http://forums.sketchucation.com/viewtopic.php?f=180&t=31448
http://groups.google.com/group/Ruby-API/browse_thread/thread/82c3f9c764171be9

---

[TIG]

You might be interested in this tool http://forums.sketchucation.com/viewtopic.php?p=371243#p371243

[iaselle]

Thank you very much TIG for your work.

Your ShadowProjector is great and I'll try to do some reverse engineering on it