Animation Group Order

Question

Using animation nodes I was able to make a procedural animation of a bridge made up of tiles coming from above and forming said bridge.

I created it by taking a plane, subdividing it 10 times, separating the faces, made them separate objects and added them to a group. I use said group in a loop subprogram for the animation.

The issue arises when the tiles come in, they come in at a weird order. I wanted to know if there is a way to control the order of which the tiles(objects) come in? Is that possible or would I have to connect hundred of objects in the correct order in an object list.

Thank you for your time!

Answer 1

First of all, blender group is not reliable as objects order.

Otherwise, you need a fixed location of objects as a reference for sorting by location. Given that they are moving around you have to consider only the final position (landed) for sorting.

This goes 2 ways:

• you use instancer to copy same object. Here you need to sort the vectors positions (vector list) that give the location of objects (instances), and not the objects

• if have a list/group of objects that are different, you have to use id key node (object submenu) to get the initial rot/loc . But first, make sure you set initial transforms (in 3d view, AN panel) for all objects. This is slightly different and I'll not detail here.

I will detail the first case

For the examples below I use the template Grid Arrange.

1. Just use the grid order This goes naturally if u use the respective template or similar.

2. Use a distance to object to sort In comparison to above, use a vector/ vector distance node to compare each position to an empty (or something else)

3. U can further use some expressions U can do the same by sorting the vector (landed positions) first as distance to or as direction as shown in the pics with formula:

distance to:

sorted(list, key = lambda item: (item - point).length_squared, reverse = reversed)

direction:

sorted(list, key = lambda item: item.dot(direction), reverse = reversed)

where the inputs are: a vector list, a vector, a boolean

Please note that in all these case I basically sort the vectors, not the objects. For the other case, you would sort the objects based on the list of (id key ) initial locations.