While using the whole OpenGL handling provided by MuJoCo Pro (C++): Is there a straightforward way to draw a straight line (i.e. a thin cylinder, or tendon) or an arrow-like vector (like the reaction forces in the simulate.cpp demo program) between two time varying points, given in global coordinates? Right now I move my visual movement 'target points' around by adding them as multiple spheres (that are excluded from collision) as geometry in the <worldbody></worldbody>. Before every visual render instance I change their positions 'm->geom_pos[i + 3 * bodyNo]' dependent on simulation time (where i = 0,1,2). This works fine. But the same 'trick' did not work for me for cylinders drawn with the 'fromto' option. I want to avoid the work-around of moving 1 attachment point around and then rotating my cylinder such that it points in the direction of the other and then scaling the cylinder length (if I find the way to do that). For example, among other uses, I would like to draw a line or arrow-vector to show the COM velocity of a moving system, or a straight line reference trajectory that changes over time. For me it is OK to have these lines as geometry in <worldbody></worldbody> or in any other way.