The talk is about modeling and simulating mechanical 3D-systems with the Julia package Modia3D.jl. Modia3D initially supports mechanical systems and it shall be expanded into other domains in the future. The package uses the multiple dispatch and metaprogramming concepts of Julia to implement features of modern game engines and multi-body programs such as component-based design, hierarchical structuring, and closed kinematic loops. The mechanical systems are treated as Differential Algebraic Equations which are solved with the variable-step integrator IDA of the Sundials.jl package.

Modia3D performs collision handling with elastic response calculation for convex geometries or shapes approximated by a set of convex geometries. A broad phase is executed where each geometry is approximated by a bounding box and only if the bounding boxes are intersecting, the Euclidean distance or the penetration depth is computed in the narrow phase with an improved Minkowski Portal Refinement algorithm.

It is planned to combine 3D modeling closely with equation-based modeling. Therefore, the Julia packages Modia3D and Modia needs to interact, for example a joint of a Modia3D system is driven by a Modia model of an electrical motor and gearbox.