Using Vendor CAD and Commercial Off-the-Shelf (COTS) Parts

What COTS means

COTS stands for Commercial Off-The-Shelf — parts you buy ready-made rather than fabricate. FRC robots are built largely from COTS: motors, gearboxes, wheels, bearings, gears, sprockets, belts, electronics, and fasteners. The major vendors include REV Robotics , WestCoast Products (WCP) / VEXpro , AndyMark , and CTR Electronics (CTRE).

Why use vendor CAD instead of modeling it yourself

When you put a motor or gearbox in your design, you want its exact geometry: real mounting hole locations, real shaft size, real bounding box. Modeling that yourself is slow and error-prone. Vendors publish official CAD so you can drop in an accurate model in seconds. Using accurate COTS CAD means:

• Mounting holes line up with what you actually bought.
• The bounding box is right, so packaging and interference checks are trustworthy.
• The model often carries the correct mass , which makes your weight estimate meaningful against the 115 lb limit (R103).

Where to get vendor CAD

• REV Robotics publishes CAD for NEO and NEO Vortex motors, SPARK MAX and SPARK Flex controllers, the MAXSwerve module and the REV ION Build System parts, and more. Their documentation site hosts downloads and Onshape examples.
• WCP / VEXpro publish CAD for gearboxes (e.g., the Single Speed/SS gearbox and the VersaPlanetary), wheels, gears, and structure.
• AndyMark publishes CAD on individual product pages — for example, their box tube extrusion (6061-T6 aluminum, sizes like 1x1, 2x1, and 2x2 in).
• CTR Electronics publishes CAD for the Kraken X60 (with integrated Talon FX), the Kraken X44, Talon FXS, CANcoder, and Pigeon 2.0 IMU.

Vendors usually offer common neutral formats like STEP (.step/.stp), which import into any CAD package, plus sometimes native SolidWorks or Onshape links.

Importing into Onshape

In Onshape you can import a STEP file directly into a Document, then insert it into your assembly. Even better, many vendor parts are already available inside FRC-specific libraries (covered in the next lessons) so you can insert them natively without manual downloads.

A workflow caution

Imported STEP parts are ‘dumb solids’ — they have no editable feature history. That is fine for COTS parts you will not modify. Keep your own designed parts parametric, and treat vendor imports as fixed references to design around.

Always verify against the real part

CAD can lag behind product revisions. Before manufacturing a mating part, double-check critical dimensions (bolt circle, shaft diameter) against the vendor’s drawing or a physical sample. A 0.030 in error in a bolt pattern can make a part unusable.

Key takeaways

• COTS (Commercial Off-The-Shelf) parts make up most of an FRC robot; major vendors are REV, WCP/VEXpro, AndyMark, and CTR Electronics
• Use official vendor CAD so mounting holes, shaft sizes, bounding boxes, and masses are accurate
• STEP is the universal interchange format; imported parts are non-parametric ‘dumb solids’ to design around, not edit
• Always verify critical mating dimensions against the vendor drawing or a physical sample before manufacturing

This lesson was adapted from learnfrc.com.