Mechatronic Concept Modeling Best Practices (Practitioner Sources)

Best-practice guidance drawn from the Siemens NX Design blog's tips-and-tricks post and from consulting-firm practitioner pages (Blue Automation, a Siemens partner focused on NX MCD implementations), supplementing the official product help with field-tested sequencing advice.

Build order: Rigid Bodies before anything else

The NX Design blog is explicit that adding physical behavior — starting with Rigid Bodies — is the foundational step that turns a static assembly into a working mechatronic concept model. Without designating movable components as Rigid Bodies (via the Mechanical tab, where mass, inertia, and initial velocity are configured), objects that are supposed to move through the production assembly simply stay static regardless of what joints, sensors, or logic you add on top.

Recommended build sequence, per the blog:

1. Rigid Bodies — establish which components are dynamic.
2. Collision Bodies — for every surface that needs to physically interact with something else.
3. Transport surfaces (e.g. conveyors) — via the Sensors and Actuators folder in the Physics navigator.

Source: https://blogs.sw.siemens.com/nx-design/nx-tips-and-tricks-mechatronics-concept-designer/

Choosing collision shapes: match the shape type to geometry complexity

A specific, non-obvious tip from the same source: for simple geometries use the Solid Body collision option with a Box collision shape; for complex surfaces (the blog's example is a conveyor belt with holes) select the Face option and use Mesh as the collision shape. Using a coarse Box collision shape on a geometrically complex surface will misrepresent the actual physical interaction (e.g., objects appearing to float over or fall through holes that should catch them); using Mesh collision everywhere by default is unnecessarily expensive from a simulation-performance standpoint. Match the collision shape granularity to the geometry.

Physics engine identity matters for expectations

Multiple independent sources (DEVELOP3D's original 2011 review of the product, and general product descriptions) confirm NX MCD's real-time physics simulation is built on the PhysX engine, licensed from Nvidia — the same physics engine family used broadly in game development and real-time visualization. Knowing this explains some observed behavior: PhysX is tuned for real-time, plausible-looking rigid-body dynamics rather than high-precision engineering-grade multibody solving. For concept-level validation (does the mechanism work, does the sequence make sense, will these parts collide) this is exactly the right tradeoff; for final quantitative engineering answers (precise force/torque values for actuator sizing), treat MCD's physics output as a good first estimate that should be cross-checked in higher-fidelity tools (e.g., NX Motion Simulation, downstream Sizer calculations) before being treated as final data — which is in fact the documented intended workflow (MCD extracts approximate force/dimension needs which feed the Siemens Sizer system for actual drive/actuator selection).

Source: https://develop3d.com/product-design/siemens-mechatronics-concept-designer/

Reuse Library as a validated-component strategy

Per the NX Design blog, the Reuse Library is positioned as the mechanism for validation and speed: it lets modelers quickly add pre-validated joints, motion definitions, sensors, actuators, and collision behavior for common components, rather than re-deriving physics behavior from scratch for every recurring mechanism (grippers, standard conveyors, common joint types). Building and maintaining an internal Reuse Library of your organization's recurring mechanisms is a practical scaling strategy once you move beyond one-off concept models.

Functional model as a cross-discipline contract

Both the blog and the original DEVELOP3D review emphasize the same organizational point from different eras: a functional model in MCD provides a common language for mechanical, electrical, and automation disciplines to work in parallel, rather than the traditional sequential handoff (mechanical design finished → then electrical → then software). The 2011 DEVELOP3D review frames this historically as MCD's original reason for existing: electrical and software teams historically had to wait for mechanical design to near completion before they could start meaningful work, and MCD's function-structure/V-model approach (especially when linked to Teamcenter requirements) was explicitly built to break that bottleneck by keeping functions traceable back to requirements from day one.

Source: https://develop3d.com/product-design/siemens-mechatronics-concept-designer/ and https://blogs.sw.siemens.com/nx-design/nx-tips-and-tricks-mechatronics-concept-designer/

Consulting-firm perspective: know when MCD is the right tool

Blue Automation (a Siemens implementation partner) frames adoption advice around fit-for-purpose use cases rather than blanket recommendation: they list mechanical engineering with high product variance, remote machine commissioning, operator training, and feasibility/cycle-time analysis requiring physics-based modeling as the scenarios where MCD provides genuine advantage, and explicitly advise conducting a comparative analysis before adoption rather than assuming MCD is always the right investment. They also cite a concrete efficiency data point from their own engagements: virtual validation of a gripper design "saved several weeks of time, as real grippers would each have had a delivery time of 3 weeks" — a tangible example of how virtual iteration avoids physical procurement lead time, not just avoiding rework.

Source: https://www.blue-automation.de/en/software/mechatronics-concept-designer-mcd