I am currently working on an orbital simulation program, and using Blender to render the paths that the various planetary bodies and satellites follow in the simulations. A feature I would like to add is a trail following each body as they move along their precomputed paths. Ideally, this would also be relatively simple to script with the Python API, and light on processing power (though that is somewhat flexible)
Currently, I have set up two potential solutions, which aren't entirely ideal:
1: At set intervals along the paths, add markers (like the primitive cube or plane), and set their visibility with keyframes (invisible at the start of the animation, visible as soon as the frame with which they are associated is passed) - this is acceptable, but it does cause a performance hit as more markers are added - rendering anything upwards of 500 frames with around 5 objects whose paths are being tracked causes adding and editing objects, as well as iterating over them all to take substantially longer.
2: Real-time extrusion of a plane - also at an interval, extrude the edge of a plane along the same path traced by the orbiting body itself - this is tricky to use, as it will require rendering as the positions are computed, rather than using keyframes (or otherwise, all the edges from the Nth one to the final one will have to be repositioned for each keyframing interval - which will definitely be a heavy load on the scene)
Is there a simple, scriptable mechanism by which to leave a trail - like a glowing line or something similar - along the path traced by a moving object in a Blender scene? Ideally, this trail should persist indefinitely, though a slow fade would also be fine.