Part Design Plus in CATIA 3DEXPERIENCE involves building complex solid features such as pockets, pads, holes, ribs, and shelled bodies that repeat across parts and product families. Managing these as individual features means every variant requires manual duplication, and every design change requires updating each copy separately.

When multiple design solutions exist for the same feature, each variation resides in a separate file with no shared interface and no efficient way to switch between them. However, with Modules and Interfaces in Part Design Plus, solid feature clusters are packaged into named modules with defined inputs and outputs. Competing solutions are registered as alternative modules under a shared parent ensuring changes propagate automatically and switching between alternatives requires just one action, with no downstream disruption.

Mechanical Designers, Conceptual Designers, Mechanical Surface Designers

Part Design Plus: Modules interfaces in Part Design Plus unlocks the ability to create and manage multiple solid geometry alternatives within a single managed structure eliminating the need for separate files per variant. A ribbed structure and a solid structure, a single bolt hole pattern and a four-bolt hole pattern each becomes a formal alternative module under the same parent, sharing the same interface contract and switchable in one action without touching any upstream or downstream geometry. This is the most immediate value addition, variant management that was previously handled through file duplication is now a controlled, reversible operation inside one part.

Beyond alternatives, Modules and Interfaces adds a formal structure to solid feature design that Part Design Plus does not have by default. Packaging solid feature clusters into named geometry modules with defined input and output interfaces allows geometry to be driven from external parameters and references, and design changes to propagate automatically across all instances. Input interfaces make the module adaptable to any part context, accepting a support face, a sketch plane, or a dimension value and rebuilding the solid geometry automatically. Output interfaces publish symbolic references, derived planes, axes, and parameters that downstream modules consume as stable named connections, keeping the design intact even when upstream geometry changes.

Use Case: Best Practices for Working with Modules in Part Design Plus.

Scenario: In the Part Design Plus design process, building features as loose, unstructured elements means that every design change requires manual updates across all dependent features. By packaging those features into modules, you establish clear boundaries and formal interface contracts, allowing a single change to propagate automatically.

However, when connecting modules in Part Design Plus, directly referencing solid BRep geometry such as a face or edge from one module to another triggers a Feature Definition Error, preventing the downstream module from building as intended.

Here, you can see how to resolve this by publishing a symbolic reference such as an offset plane or parameter as an output interface from the upstream module and consuming it as an input interface in the downstream module. This approach allows all dependent geometry to update automatically without crossing the BRep boundary.

Play the video to watch the implementation of Modules and Interfaces for improved model robustness in Part Design Plus.

To learn more about Modules and Interfaces, You can refer Explore the Mechanical and Shape Engineer Role Learning Module.