Recent attention has been focused on the assignment of behaviors to graphical entities. Most of these behaviors are targeted for the runtime environment. By defining modeltimeTM behaviors, behaviors whose sole purpose is to help with the task of modeling and whose scope is limited to the modeling environment itself, great gains in productivity can be realized in rapid assembly tasks.
"Increased productivity through Modeltime behaviors", Proc. SPIE 2409, Stereoscopic Displays and Virtual Reality Systems II, (30 March 1995); doi: 10.1117/12.205867; https://doi.org/10.1117/12.205867