Arc tracking joints

A question came up in our group on how to arc track Ballie’s knees, so thought I’d show how to do it step by step as it’s quite useful.

1. Open up ballie.
09_arcTrack_01

2. In your perspective window click on Show and make sure Joints is ticked and turn off Nurbs Surfaces. Most of Ballie should disappear.
09_arcTrack_02

3. Create a polygon sphere and snap it to the knee joint by holding down v when you move it. Duplicate the sphere and move the 2nd sphere to the other leg.

Grab one sphere then Shift+select the knee joint it’s placed on and press P. Do the same for the other leg.

09_arcTrack_03 

5. It might be worthwhile placing both spheres in a new layer, this way you can hide + show them easily. I also did this again for the ankles, but later realised the heels are a better place to track.

09_arcTrack_04

6. Go back to Show and uncheck the Joints and check Nurbs Surfaces to bring them back. If you move his legs around the balls should follow. If so, save your Ballie file. 09_arcTrack_05

6. Go back to your animation, if you click on a sphere you should now be able to track it.
09_arcTrack_06_2

**I should at the time of writing this post we were using a different arc track tool. Thanks to Ben for this heads up in the comments:
“One additional step I needed to take was set a key on the first frame on each sphere, then I could see the arc using ‘Create editable motion trail'”.

2 thoughts on “Arc tracking joints

  1. Ben Boyle

    super useful Tim, thanks! one additional step I needed to take was set a key on the first frame on each sphere, then I could see the arc using ‘Create editable motion trail’ (there’s no other arc tracking option is there?)

    Reply
  2. admin Post author

    Ah cheers for that. When I wrote this post we had access to a different arc tracking tool, which in my opinion was better than motion trails. Will update the post, thanks.

    Reply

Leave a Reply

Your email address will not be published. Required fields are marked *