CATIA Assembly Design: Flexible vs. Rigid Sub-Assembly

When adding an existing sub-assembly into the main assembly, it is added with the default state of Rigid. The tree symbol for Rigid sub-assembly is with the top left gear in blue: .

The Rigid state means that the position of the components in the sub-assembly will not change from one instance of the sub-assembly to another.

Consider the example of the tooling table, in which there are three instances of the Vise sub-assembly.



As long as the sub-assemblies are in the default Rigid state, changing the distance between vise jaws in one sub-assembly changes the distance between the jaws in all of them.


In the Flexible state, the positions of the components within the sub-assembly can be managed independently for each instance of the sub-assembly.


To change the state to Flexible, select the instance of the sub-assembly in the tree, right-click and select Flexible/Rigid Sub-Assembly in the contextual menu.


The tree symbol changes, now with the top left gear in purple: 

Once the Vise sub-assemblies have been changed to the Flexible state, the distance between the jaws can be changed independently for each instance of the sub-assembly.



In the Flexible state the positions of the components within the sub-assembly are managed and saved at the level of the main assembly product file.

For more information, Assembly Design in CATIA is covered in the Introduction to Modeling and Advanced Assembly Design and Management Rand 3D training classes.

About the Author

Iouri Apanovitch

Senior Technical Training Engineer<br><br>As a senior member of the Rand 3D team with a doctorate degree in Finite Element Analysis (FEA) and over 35 years of experience, Iouri provides design, consulting, and training services to those in the aerospace, automotive, electronics, and consumer goods industries. Iouri is a seasoned pro in 3D parametric design and prototyping using knowledge-based engineering methods, and has worked on a wide range of projects including BOM automation, CMM points generation, automated 3D annotation creation, and die tooling automation design. He is also a sought-after instructor and holds the designations of both CATIA Certified Professional (Expert level) and CATIA Certified Instructor.

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