Partial Path Extrusion

I have no Python background, but I saw this ILM guy perform a partial path extrusion in Maya (and I learned). I wanted to do it in Blender, but I don’t think its possible- so I wonder if anyone knows how to script that, or point me in the right direction for accessing the proper commands.
Basically, it would work off of the [evaluation time] and extrude the path only up to the current time. Kinda like a ribbon growth. This way you could animate the extrusion. I guess it would be called as a linked object script??

I know the other ways- but this seems a whole lot simpler for clean growth effect.
Any thoughts on how to build it would be great- mocking it up would be better! But I would like to know how its working also…

Here is what I’m referring to:

and… I found this Bevel script (non-secure):

Have a look hier, rotoscoping used :wink:

Rotoscoping is clever, but it definitely would be easier to build it from a script. How would I access the path length data in a path? Would I have to perform the extrude algorithm, or simply hack the process to stop before it completes the extrude based upon frame number?