Getting the matrix on a specific frame.

[matroxI]

I have an empty object that is parented to 3 vertices of a mesh. I want to get the matrix of this empty, but not at the current moment, but with a delay of 4 frames. Sorry for such a basic question.

[OmarEmaraDev]

You can try to use the Evaluate FCurves Transform node for that, see for example:
https://docs.animation-nodes.com/release_notes/v2_3/#evaluate-fcurves-transforms