I have recently have a look into the obj files in AFP, trying to create a 3ds max I/O plugin, I have a few questions:

1.what are the lines started with 'q' for, ie: "q 3 147 147 148"? it seems to me its some sort of vertex indices, but what are they for?
2. what are the lines started with 'ch' for?, this one is totally lost me
3. what are the lines started with 'chp' for?, it seems to be some sort of normal vector, what are they for?
4. what are the lines started with 'chf' for?, it seems to be some sort of vertex indices again, what are they for?

It seems there are more than just the 3d object data in the obj file. I can pretty much reconstruct a 3d object with information only up to 't' in each section. Does AFP use the rest of the data for some other unknown purpose?

Hi,

1. the 'q' lines not only describe a single triangle as the 't' lines do.
They describe an entire queue of faces, which seems to speed up the processing in the simulation.

2. The 'ch' line is the start line of the convex hull

3. The 'chp' stands for convex hull points and is just a point coordinate

4. The 'chf' then contains the convex hull faces from the points above.

The entire ch.. set creates a framework around the aircraft, which is used for crash detection.

Regards
Rodeo
www.rodeo.onlinehome.de