[Chimera-users] bond transparency as a function of length?

Hi, Very recent to Chimera. Trying to set the transparency of a bond to be a function of bond length in each frame of a trajectory. I have figured out how to define a transparent color, and now I am imaging the solution might use something like range color to vary the blending of the opaque version of the color and the fully transparent version based on distance, with the distance being determined as a per frame attribute of those atoms, but someplace around here I am lost. Any hints, links or suggestions would be very much appreciated. Cheers, KB