The Math Forum

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

Advanced Search

Back to Topic List Back to Topic List Jump to Tree View Jump to Tree View   Messages: [ Previous | Next ]
Dave Rudolf

Posts: 37
Registered: 10/3/05
Pivot point for two bodies
Posted: Jan 8, 2009 8:46 PM
  Click to see the message monospaced in plain text Plain Text   Click to reply to this topic Reply

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 ball-and-socket 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



Point your RSS reader here for a feed of the latest messages in this topic.

[Privacy Policy] [Terms of Use]

© The Math Forum at NCTM 1994-2018. All Rights Reserved.