Can you use vertex Weight as falloff? My question is how I could use vertex paint as falloff.
My goal is to make something just like with a object falloff but when the object falloff is gone over a polygon it must stay "disappeared".

I know you could do it with a paint modifier and after that a mask modifier and use the weight group made by the paint modifier but the mask modifier does more of a "cut" than slowy dissovling the poygons + in animtion nodes you have more control over the how the animtion plays.

I think the problem is in difference in list lenghts after you use the "Prepare Polygon Transformation" node but I can't a solution or a work-a-round.

So I hoped someone here could help me
Welcome to Stackexchange! You are trying to transform polygons based on weights of vertices, so your current approach wont work as you expected.

Instead, you need to somehow compute a weight for each polygon based on the vertices that make it. One way is to take the average of the weights of the vertices of each polygon. To do so, loop over the polygon indices, get the weights at those indices and average them:



Then you can use the Offset Polygons node to transform the polygons based on the custom falloff just as you did. There is no need to extract the polygon info or recreate it, the Offset Polygons node takes care of this: