blender - Animation Nodes - change scale of objects inside the collection with fall off?

Question

I'm using Blender 2.91 and Animation Nodes 2.1.8. So far, I have half-working solution to my problem, but I am stuck, when I try to make it work 100%.

Simply, I want to animate a number of objects within a Collection, using a Spherical Empty. Empty scale goes up, objects scale animate as well to 100% with some sort of Fall Off in place. Basically a Cinema 4D effector.

Here is how my Animation Node tree looks like:

Null at Scale of 20 - all objects are scaled to final size I want

Empty scaled down to 0.1 scale - objects nearly gone - so far so good

When empty reaches 0, objects go back to their starting scale

and I don't know how to fix that. I suspect it is because, I am using Vector Math to Subtract Empty scale from Objects. And when Empty Scale reaches 0 - objects go back to their initial size?

Is there a better Animation Nodes set up?

Second question is, is it possible to affect all objects at once with a fall off to animation smoother? At the moment objects scale quite rapidly, but I would prefer they scale more gradually? For example the ones in the centre are at 100% and the ones at the edges at like 10% so it looks nicer?

GIF to help visualize what is happening

I just joined Stack Overflow, so can't embed images directly yet. But I hope the links will illustrate my problem.

question from:https://stackoverflow.com/questions/65852413/animation-nodes-change-scale-of-objects-inside-the-collection-with-fall-off

Answer 1

I think I figured out.

Animation Nodes set up:

There was no need for Map Range node. Simply, set Fall Off on Empty for smoother animation and make sure Invert is checked. Then animate empty scale. Offset Matrix should have Scale set to 0.

Also, place an empty 7m in Z space above the collection/objects, if you are using Fall Off Width. This way Fall Off won't affect it, when empty Scale is 0.

And done. Empty scales to 20 and all the objects animate from the centre to outside with a nice Fall Off.