SendCutSend Community College is a step-by-step video series designed to teach computer-aided design (CAD) from the very beginning. Whether you’ve never opened a CAD program or you’ve dabbled and want a structured path, this series will guide you from the basics to designing real, manufacturable parts you can bring to life with SendCutSend’s cutting and finishing services.
You can access all lessons on our website sendcutsend.com/education and on YouTube.
If you haven’t gone through Chapter 1: Getting Started with CAD, you’ll want to start there before jumping into Chapter 2. Here’s what you can expect in this Chapter.
Chapter 2: Building Complex Geometry
Lesson 1: How to Reverse Engineer Parts in CAD
In this chapter, we shift from learning CAD tools to designing with intent and building real parts that can actually be manufactured. In the first lesson Jake introduces reverse engineering, where we take an existing object, in this case, an Arduino Uno circuit board, and recreate its essential features in CAD. Instead of modeling every tiny detail, we focus on the key dimensions that matter: the overall rectangular outline, the mounting holes, and critical ports like USB, power, and the reset button. You’ll learn how to measure these features with calipers, apply them in your CAD program, and create a fully defined, robust sketch.
Along the way, we’ll explore simple measurement tricks for hole spacing, highlight why it’s best to capture only what’s necessary, and show how you can use sites like GrabCAD or Thingiverse when you need ready-made STEP files. By the end of this lesson, you’ll understand how to design around real-world parts, setting the stage for creating a custom enclosure and moving into assemblies with joints in the next lesson.
What you’ll learn:
- The importance of designing with intent in CAD
- How to reverse engineer real-world parts for your projects
- Using calipers to measure overall shapes, hole locations, and port positions
- Quick methods for calculating hole center-to-center spacing
- Why focusing on only the key features keeps designs simple and effective
- How to create a robust sketch in CAD for the Arduino Uno
- When to download existing models (GrabCAD, Thingiverse) vs. sketching from scratch
Lesson 2: How to Create Assemblies in CAD with Joints
In chapter 2 lesson 2, we move deeper into assemblies by learning how to create references between parts using joints. After reverse engineering the Arduino Uno board in the previous lesson, we now insert it into a new main assembly file to keep things organized and reusable. Instead of building everything around a single part file, this approach lets you reference the Arduino in multiple assemblies without duplicating work or creating unnecessary clutter.
We cover how to insert the component, manage its link to the original file, and understand options like grounding and ungrounding. From there, we explore the Joint tool, which locks parts together in precise ways. You’ll see how to use a rigid joint—like “super glue”—to attach the Arduino to the origin, ensuring it’s properly anchored in space. We also touch on the different types of joints available (rigid, slider, ball, etc.) and how they can allow controlled motion in more complex assemblies. By the end of this lesson, you’ll have a solid Arduino component placed and fixed in your assembly, ready for designing the enclosure around it.
What you’ll learn:
- Why assemblies in CAD need references to connect parts
- The benefits of creating a main assembly file instead of building everything into one part file
- How to insert a component and manage its link to the original file
- What it means to ground or unground a component
- How to use the Joint tool to fix parts in place (rigid joints)
- The difference between rigid joints and more advanced motion joints
- How to precisely align a part (like the Arduino Uno) to the origin in your assembly
- Setting up a clean, reusable assembly ready for building enclosures and more
Lesson 3: How to Use Offset Planes and Project Sketches in CAD
As we dive deeper into designing real parts in CAD, one of the most important skills you’ll need is controlling space and clearance between components. Not every part sits flush,sometimes pins, connectors, or other hardware extend past surfaces, and you need to account for that in your design. That’s where offset planes and projected sketches come in. These tools let you create precise references in space, add the right amount of clearance, and build features like enclosures that actually work when manufactured.
In chapter 2 lesson 3, we continue our Arduino enclosure project by offsetting the bottom of the box away from the board’s pins and projecting the Arduino’s outline and mounting holes onto a new sketch plane. This ensures the box fits correctly, the ports align, and the design is clean and manufacturable.
What you’ll learn:
- How to create offset planes to add clearance between parts for hardware or connectors
- How to project geometry from one body onto another plane for accurate positioning
- Using calipers to translate real-world measurements into CAD features
- Designing the base of an enclosure with proper spacing and port alignment
- Applying two-sided extrusions to control both upward and downward dimensions
- Organizing your model with named components for a clean, scalable assembly
Lesson 4: How to Use Shell, Fillet, and Analysis Tools in CAD
In chapter 2 lesson 4, we take our Arduino enclosure design further by hollowing out space for the board and refining the box with professional finishing tools. You’ll learn how to use the Shell feature to create an internal cavity, how to add fillets (rounded corners) for cleaner design and improved fit, and how to leverage the Analysis tool for an X-ray view of your model. These tools not only help ensure your part looks good but also verify that components fit together correctly without interference.
What you’ll learn:
- How to use the Shell tool to hollow out a box and create internal voids for components
- How to apply fillets (corner radii) for smoother edges and cleaner geometry
- How to identify and fix interferences inside your model
- Using Section Analysis for X-ray vision to inspect fit between multiple parts
- Best practices for refining enclosures and assemblies
Lesson 5: How to Reference Bodies for Clearance in CAD
In chapter 2 lesson 5, we finish the bottom half of our Arduino enclosure by adding mounting pads and creating clearance for the USB and charge ports. You’ll learn how to use projection and offset tools to reference one body against another, ensuring that features like holes and ports are aligned correctly. We’ll also cover how to manage extrusions with “to object” references for flexible designs that update automatically when parts change. By the end, you’ll have a fully prepared bottom box, complete with standoffs and cutouts, ready to pair with a lid in the next lesson.
What you’ll learn:
- How to reference bodies in CAD to ensure proper clearance and fit
- Using the Project tool to transfer geometry from one body to another
- Creating mounting pads with “to object” extrusion for parametric flexibility
- Adding USB and charge port cutouts with offset dimensions for manufacturability
- Best practices for preventing mistakes when cutting across multiple bodies
- Finalizing the bottom enclosure of your design before building the lid
Lesson 6: How to Design a CAD Lid with Joints, Ventilations & Access Features
In chapter 2 lesson 6, you’ll take your Arduino enclosure one step further by creating a referenced lid component directly from the bottom box. You’ll learn how to properly join components so the lid doesn’t float in space, while also adding design features for real-world functionality like ventilation, a reset button hole, and wire access. This lesson highlights the importance of referencing existing parts when building new ones, ensuring your design stays aligned and functional.
What you’ll learn:
- Create a new component (the lid) based on an existing part in your assembly.
- Use joints to connect components and lock them in space.
- Add locating features (like slip-fit extrusions) for proper alignment.
- Design ventilation slots to handle heat buildup.
- Project references for functional details like a reset button hole.
- Cut wire access slots and manage which components are affected.
- Apply design-for-manufacturing (DFM) thinking when adding features for 3D printing.
Lesson 7: How to Repair Broken References in CAD Assemblies
In this final episode, lesson 7, of Chapter 2, we explore how to make changes to your CAD designs without starting from scratch by leveraging parametric design. You’ll learn how updates made to a referenced part (like our Arduino board) propagate through the assembly, and how to troubleshoot when references are lost or errors appear. By walking through real examples—lengthening the Arduino and relocating a reset button—you’ll see how to repair broken references, update features, and keep your assemblies flexible and functional.
What you’ll learn:
- How parametric design keeps your assemblies adaptable to changes
- Updating a referenced component and syncing it with the main assembly
- Identifying and fixing lost references when parts or features are removed
- Using the timeline to trace and repair errors step-by-step
- Projecting new geometry to replace missing features
- Best practices for keeping assemblies robust as designs evolve
What’s Next?
New chapters will drop week, taking you deeper into CAD and eventually into design for manufacturing, where you’ll learn how to prepare your projects for real-world production.
Ready to sharpen your CAD skills and start turning your designs into reality? Head to the SendCutSend Education hub and follow along on YouTube.
