CompuServe Thread

#SXP object coordinates

4 messages in this thread
#76284From: Aaron D. YonasJan 14, 1994 10:38 AM
Could anyone tell me exacty how the the object coordinate system is derived? What is the relationship between its origin and the world origin? Are its basis vectors (the direction and scale of its x, y, and z) the same as the world's? Just to be sure, by object coordinate system, I mean the parameters passed to an SXP via Sxpdata p[3]. My current guess is that the object coordinate origin is the center of the object's bounding box (as defined in the world coordinate system). Is this right? Thanks in advance, Aaron
#76302From: Jonas Ruikis [ADESK]Jan 14, 1994 11:46 AM
Aaron, I'll look into this question and I'll get back to you. jonas[adesk]
#76314From: Phillip L. MillerJan 14, 1994 12:31 PM
Your correct, it is the bounding box as it related to the global axes at the time of creation and its origin is the bounding box's local axis. This is the object's "transformation matrix" and it moves with the object during its movements, rotations, scales, etc. so it will not always be "square to the world". Only commands that create the object at the face level (such as Create/Face/Detach) will reset the bounding box, whereas it can now be reset at any time with Reset XForm.
#76608From: Aaron D. YonasJan 16, 1994 3:52 AM
Phillip, Thanks! It did help — a lot! I probably wouldn't have stumbled across Reset X-form for weeks! Aaron