Motion path drawing code (drawanimviz.c) is not currently implemented in 2.8, meaning that old files with motion paths and/or files where motionpaths have been freshly calculated do not show up.
**Branch / Current Code**: `tmp-b28-motionpath-drawing`
* This should work as an overlay (visible in the overlays popover), so that it can be turned on/off independent of other stuff we draw in the viewport. It should not be tied to manipulator/relationship line visibility.
* Motion paths work with both objects and bones. They can either be defined on Object Level (e.g. ob->mpath), or Bone Level (e.g. pchan->mpath)
* The old drawing methods use immediate mode. Could/should be optimised.
* Appearance could be updated a bit - for example, thicker/nicer line quality + shading, different ways of visualising the keyframe positions (e.g. with lines perpendicular to path - similar to what animators use for timing charts - [ [[http://profspevack.com/archive/animation/course_cal/week05/week05.html | 1]], [[http://www.brianlemay.com/Pages/animationschool/animation/lipsyncbook/timingcharts.html | 2]] ]