How to create an animation by choosing rows in a matrix to switch with time. Truss simulation

I downloaded the following files from:

Frank McHugh (2020). Truss Analysis (LINK), MATLAB Central File Exchange. Retrieved April 1, 2020.

I have edited them for my project which is to create a 3d model of a truck(lorry) going over a bridge. The members in the bridge will change colors based of the force applied to each member, and that force changes as the lorry goes across the bridge. I have the animation of the lorry moving across the bridge, but I need help figuring out how to make the forces within the bridge change rows in the matrix F based on the position of the lorry. I attempted it in the bottom but no success.

Answer 1

[darova]

Here is my achievement: i just scaled colors while moving