There are tons of things that affect rendering times.
The big questions would be:
- How large must the images be
- How many frames are you doing
- What would you consider to be an acceptable time limit for each frame
I just finish a project with 2,550 frames @1,536 x 864 that averaged 2 min 20 sec per frame ( 4.5 days ). For me that is a long time in this day and age because I'm used to 20-30 seconds to render each frame. ( The models had tons of glass panels) I could have cut this time in half if I had used one on newer machines, but didn't want tie it up for a couple of days.
Things that can cause render times to increase:
- Highly reflective materials
- Rounded surface or corners
- Too many light sources
- Refraction and reflections settings that are too high
- Background materials that are too detailed
And last but not least, throw as much hardware at the process as you can and keep that machine as lean as possible as far as the number of processes that are running in the background.
I use a larger than required frame size so that I can use a resizing filter as I compile the movie. My final frame size is 1,280 x 720 ( 16:9 HD in You Tube ). It takes a bit longer, but the final results are better.
The stepping thru the path shouldn't be the time issue. So whether its is done thru lisp and any other programming language should take about the same time. I would guess it take 1 second or so to transition from 1 frame to the next. It's the rendering engine. ( I take you are using AutoCADs built in render. )