making the footprints is not the issue
(and thx Andy will check out Sparrowhawk)
it is the animated placing as the figure walks.
hence the need for a cummulative image series to place in the displacement, or just bump and layered diffuse map
making a series of images to match the footsteps easy enough but getting them to add in each consecutive frame my issue
needs to be a series of alpha mapped images that do not show the sole when not in contact with the ground.
hence a view of black feet invisible figure, below a shadowcatch plane with penetration against a white BG
but you can see from my layered in Gimp gif’s I cannot get the footprint forming effect.
I would do as Man suggested. You could do an animation to create it, but it’s not just a matter of turning the footprint “on.” You’d want to fade the effect in. The print would be the same color as the the rest of the displacement map, but as the “weight” is put down, the print would darken, thus making the indentation deeper. Any video editor that handles layers or can otherwise composite should be able to handle it. You would need to time your stride and match the figure to the footprints.
I recall a thread a long time ago in the old forums where someone talked about trying some kind of magnet or deformer to do the job. I can’t recall how that worked unfortunately.