CATIA

CATIA (Computer-Aided Three-dimensional Interactive Application) is an extremely powerful CAD package providing designers advanced surface modeling options, sophisticated linking of content within and between model files, efficient assembly management, and many simulation tools. Its high cost restricts its use to aerospace, automotive, and the largest consumer goods companies. I first used CATIA at Stanley Black and Decker in 2023, achieving basic proficiency within 4-6 months and advanced understanding by the end of my first year. CATIA is the CAD software I have the most experience with for professional use.

To comply with the policies of companies which I have produced CATIA content for, I am unable to directly share any original work here. As an alternative, below are some broader descriptions of my experience with CATIA:

• My design approach with CATIA:

  • Leveraging master/skeleton modeling techniques to optimize data reuse, streamline links and keep several parts synchronized. This has become my non-negotiable for any assembly containing three or more parts.

    • One parent file (skeleton) containing only 1D and 2D geometry (points, lines, curves, sketches, planes, surfaces, etc.) that define crucial geometry and intersections between parts. Essentially, all design decisions are made here.

    • Each component is a child of the parent, linking to the content relevant to just that component's design. Each component is just a permutation of elements derived from the skeleton, to be toggled on or off.

  • Thorough use of construction geometry to create support features accessible by all features. I attempt to never create sketches directly on solid faces if possible, instead defining a plane as the solid extrude limit and sketching on the plane. This ensures sketches are never orphaned from their supports.

  • Boolean-based modeling where features are compartmentalized into small pieces with limited scope. This prevents cascades of errors and creates a modular design where one iteration of a feature can easily be replaced by another. CATIA facilitates this very well, with solid bodies being the basic building block serving as containers of features, rather than strictly an output of positive operations (pad, revolve, sweep, etc). 

  • Performing operations as early in the design tree as possible to minimize dependencies; ex. create a fillet as soon as its parent edge exists, rather than after the creation of potential conflicting features.

• Special modeling skills:

  • Cavity-core modeling techniques, which actually model the cavity-electrode and core of the mold, producing the part as the negative space between the two. This guarantees no mechanical conflicts in the injection molding process to product the part.

  • Familiarity with injection molding best practices

  • Modeling of wire harnesses and connectors, including wires in both routed and stock states to ensure ample space and compliance with minimum bend radii

  • Fundamental understanding of industrial design principles that contribute to a product's sense of identity and value

  • Bent sheet metal design using stock material thicknesses and industry-proven principles on feature layout

  • Driving sketches, which consolidate relevant geometry together and allow for changes to enacted from one source

  • Orderly linking, creating robust models that won't break due to changes in context

  • Use of formulas to parameterize models wherever possible, accelerating iteration speed

• Drawings:

  • Created part drawings of precision components up to 0.001 mm

  • Applied surface finish callouts to shafts

  • Utilized GD&T (Geometric Dimensioning and Tolerancing) with feature control frames to quantify tolerances for holes, profiles, etc.

• Parts:

  • Created parts for many different purposes:

    • Electrical (strain relief grommets, terminal boxes, cable routing features, custom PCB mounts)

    • Mechanical (motor housings, interface plates, mounting brackets, motor shafts)

    • Airflow (baffles, fans, venting)

    • Testing (angle dials, tool fixtures, jigs)

  • Verified part design using draft analysis and other tools

  • Extensive use of construction geometry (planes, axis systems, lines, points, etc.) to support features

  • Created reference models of existing industry products from technical documents

  • Imported external models of stock components for use in designs

  • Exported parts in additive manufacturing formats (.stl, .3mf)

  • Utilized links to parameters and equations to drive models

  • Surface modeling, use of surfaces to modify or produce solid volumes

• Assemblies:

  • Created assemblies with 100+ parts and many mates

  • Organize top-level assemblies into sets of logical sub-assemblies, grouping parts that share a purpose (fasteners, interface elements, etc.) or which will be assembled together beforehand

  • Verified assembly design using clash checks to identify incorrect fits between parts

  • Widespread use of coincident mates between components to remove all degrees of freedom and precisely locate parts

• Simulation:

  • Created simulation test plans outlining design changes to be examined

  • Set up mechanical, thermal, and CFD airflow studies (boundary conditions, control volumes loading method(s)/speeds, material, etc.)

  • Produced reports with relevant results (isosurfaces, particle studies, flow diagrams, cross section views of velocity/pressure/temperature, mechanical stress, deformation, displacement, factor of safety, etc.)

  • Synthesized results into actionable changes and quantified improvements in performance

Example of the Master/Skeleton modeling approach, using a common door:

Wherever two parts contact one another, there is typically information shared by both parts. This means when one part needs to change, it will likely affect parts it contacts with.

For the example above, the door body contacts both the hinges and the knob, so information about the knob (in yellow) and about the hinges (in blue) need to be accessible by each pair of parts. If the size of the knob changes then the hole in the door must change to match; if the fasteners attaching the hinges to the door change from M6 to M8 then the holes in the door must be enlarged. Within the hinge sub-assembly itself, the bracket and pin are in contact for their entire length, and so it is convenient to define both parts' size from the same diameter andset of limit planes.

For a task like this, I would make sketches like those above to determine shared construction features between parts, then structure the files like the diagram below. Storing circled common content in the Master Skeleton File allows all parts remain synchronized and reduces the definitions of the content from sixteen to to seven.