Animating with expressions

When using expressions to make an object follow another I noticed that the position of the object that has the expression doesn’t update automatically when you move the ‘parent’ object. I have to pretend I’m editing the expression again and click apply to see the changes. This pretty much make expressions useless, unless its something you’re adding to the scene after you’ve already finished animating. Is this how it is supposed to work?

I wrote a script that updates all the expressions values. Visit next monday to download.

What about when you save the project after doing the movement of the original object?

I tried your suggestion, but it doesn’t update. Another thing that works is closing and opening the file again, but it isn’t practical.