Hello Brian,

I had a look to the code. I'm sure you will not find a bug. It seem that the line 35 generates the problem.
The function to create the vector-display works as follow:
- creating a line with length 1 and a cone for the tip of the base vector display
- orient this base vector display to start and end of the vector that should displayed by using "factory('orientlinetoline', that.bVec, bPt0, bPt1, tPt0, tPt1, null, 'scale, stretch');"

but it seems that here is a problem - orientlinetoline generates weired results (tested with MoI V3) when the target has the same orientation as the start orientation especially in the main directions. After the factory is initialised and get other inputs (not in the main dirs) everything works fine as espected. Maybe Michael have a look.

Which Version do you an Pilou use at the moment.

A nice day to all
Karsten