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CAD & Design·Lesson 4 of 31

Why FRC Teams CAD Their Robots

Understand what CAD is, why nearly every competitive FRC team designs the whole robot digitally before building, and what 'good CAD' buys you during the short build season.

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What is CAD?

CAD stands for Computer-Aided Design. In FRC, it means building a complete, accurate 3D model of your robot on a computer before you cut a single piece of metal. Every tube, plate, gear, motor, bearing, and bolt exists in the model, positioned exactly where it will go on the real robot.

Modern FRC CAD is parametric, which means the model is built from a recipe of features (sketches, extrudes, holes) driven by dimensions. Change one dimension and the model updates everywhere it matters. This is what lets a designer say 'make this gearbox plate 0.125 in thicker' and have the whole assembly stay correct.

Why bother? The build season is short

FRC gives teams roughly six to eight weeks from Kickoff to their first competition. Building the wrong thing wastes irreplaceable time and money. CAD lets you:

  • Catch interference before you cut metal. The software flags when two parts occupy the same space, when a motor won't fit, or when a bolt has no clearance.
  • Check the rules. You can verify your robot fits the legal envelope. For 2026 REBUILT, rule R104 says the robot's starting configuration may not have a ROBOT PERIMETER greater than 110.0 in and may not be more than 30 in tall; R103 caps weight at 115.0 lb without bumpers and R408 caps it at 135.0 lb with bumpers.
  • Plan manufacturing. A finished model produces a parts list and drawings so the build team knows exactly what to make and buy.
  • Communicate. A 3D model is the single source of truth that mechanical, electrical, and programming sub-teams all reference.

CAD is part of a bigger process

CAD does not start at Kickoff. It comes after your team has analyzed the game, picked a strategy, and prototyped key mechanisms. CAD turns a proven prototype concept into a precise, buildable design. Treat the model as a living document: as prototypes teach you things, you update the CAD, and as you CAD, you discover constraints that send you back to prototyping.

A realistic FRC CAD workflow

  1. Strategy and prototyping decide what mechanisms you need.
  2. A layout sketch lays out the major dimensions and how subsystems fit together.
  3. Designers model each subsystem (drivetrain, intake, scorer) as parts and assemblies.
  4. COTS parts (motors, gearboxes, wheels) drop in from libraries.
  5. Drawings and a bill of materials feed manufacturing and purchasing.
  6. Design reviews catch problems before anything is built.

Learn this loop and you become the person who turns ideas into a robot.

A great starting point is the free FRCDesign.org Learning Course, built by experienced FRC CAD mentors.

Key takeaways

  • CAD is a parametric 3D model of the entire robot built before manufacturing, used to catch problems, check rules, and plan the build
  • The short FRC build season makes designing-before-building essential, not optional
  • CAD follows strategy and prototyping; it turns a proven concept into a precise, buildable design
  • The 2026 REBUILT rules define the legal envelope your CAD must respect: R104 sets a 110 in perimeter and 30 in height; R103/R408 set 115 lb (no bumpers) / 135 lb (with bumpers)

Go deeper

Lesson quiz

Required

Answer all 3 questions correctly to complete this lesson.

1.What is a primary reason FRC teams CAD their robot before fabricating parts?

2.How does a CAD model help FRC teams during the manufacturing stage of building a robot?

3.Why is a shared CAD model valuable to an FRC team as a whole, beyond a single designer?

Answer every question to submit.