An History-based Binary Tree for Assemblies

Most of commercial CAD assembly modules are based on a geometric entities constraining. DOF between surfaces (or faces), axis alignments and point-to-point constraining are targeted to a final product digital mockup. The assembly components are not specifically time sequenced and ordered and the assembly simulation is targeted to improve and optimize the component interaction. The final assembly appears in a thorough group and subgroup tree, but a correct subsequent action based assembly is hardly deducible. In this paper a binary tree for mechanical assemblies is proposed and implemented. The time (or action) sequence is recorded and stored in a parallel data structure called BAT (Binary Assembly Tree), directly by the operator, avoiding complex automatic assembly sequence extraction from geometry. The BAT has been also provided by an addictive algorithm, which allows the incremental interactive check of large mechanical assembly components in case of direct connection with Mixed Reality systems.