Search All of the Math Forum:
Views expressed in these public forums are not endorsed by
NCTM or The Math Forum.


Math Forum
»
Discussions
»
sci.math.*
»
sci.math
Notice: We are no longer accepting new posts, but the forums will continue to be readable.
Topic:
Pivot point for two bodies
Replies:
2
Last Post:
Jan 9, 2009 7:42 PM




Pivot point for two bodies
Posted:
Jan 8, 2009 8:46 PM


Hey folks,
I am trying to find pivot point locations for two connected objects by filming them and analyzing their relative positions to each other. So, for a simple example, suppose we have two rigid bodies connected by a ballandsocket joint. Now suppose I am tracking features/markers on the two objects with cameras, and triangulating multiple camera views to get the 3d locations of those features.
So, if I have three features on one object, I can determine the position and orientation of that body over time. If I then have at least one feature on the other object, I can transform that feature's position into the coordinate system of the other object. So, that feature will sweep across the surface of a sphere, relative to the other object, and the center of that sphere is the location of the pivot point. Problem solved.
Now, suppose I only have two features on each object. I can't find an exact position and orientation for either object by themselves. So, has anyone heard of a way to determine the pivot location in this case?
Thanks.
Dave



