Animating Constraints...

(Nayman) #1

Okay… i want something to a ball to follow an empties location perfectly, and then stop, and then start again, but the empty keeps moving the entire time.
How can i animate the Influence of a constaint to be 100% and then in the course of 1 frame, 0%?

(theeth) #2

try giving a look at that example file:

thanks to Slikdigit for explaining the technique the first time.


(harkyman) #3

Yeah, it’s a great technique. The actions you need to take to set a constraint key aren’t really intuitive though, so I’ll give you the easy rundown:

You need to have three views available: 3D window, constraint buttons, and ipos.

  1. Set your constraint (copy location, etc.) . On the slider to the left of the constraint, set your influence value (0-1).

  2. In the ipo window, make sure that you are displaying CONSTRAINT ipos, the little chain link at the bottom.

  3. In the buttons window, click on the EDIT IPO button immediately to the right of the constraint influence value you set in step 1.

  4. Left-click on the “inf” in the upper right hand corner of the ipo window.

  5. Ctrl-left-click in the workspace of the ipo window. Every time you Ctrl-LMB in this window, it sets a new key.

You can decide how you want to do it from here on out, but here’s how I work with it…

I figure out how many keys I’ll need to get the effect I’m after, then Ctrl-LMB that many times. The horizontal axis represents what frame you are on; the vertical axis indicates constraint influence. I hit tab to edit the keys directly, then select each in turn and set their values numerically with the N key. If you want a hard start and stop to the constraint, say to have something be uninfluenced on one frame but locked down the next, you can change the whole ipo to “linear” by pressing the T key.

Have fun!

(Nayman) #4

hey thanx guys…

it’s for my spidey movie… :Z