CAD Support

Why CAD?

CAD is a critical engineering tool used to capture design intent, get ideas out of your head, and help make stuff.

Which Software Should I Use?

We primarily teach Onshape because it is a CAD program that is:

  • Free for university students, faculty and staff.
  • Easy to learn using Onshape’s tutorials.
  • Browser- and cloud-based. Works on any computer that has a browser (Mac, Windows, Linux…) and does not require extra software to be installed. Hardware requirements are significantly less for Onshape than for installed desktop CAD programs (e.g. memory, processor speed, graphics).
  • Great for collaborating. It’s often referred to as the “Google Docs of CAD” since files can be easy viewed and/or edited among teams. 
  • A real engineering tool. Onshape was created by the founder of Solidworks (article), so this is not your typical freeware CAD software.

Create a Free Onshape Account

Other options at UW-Madison College of Engineering (Solidworks, Autodesk, NX, etc.):

CAE CAD Software List

CAE Computer Labs

Citrix Remote Use Through a Browser

CAD Help

Our staff is available at the times below (during the semester) to help you get started with CAD or answer specific questions.

Drop in Support
Tuesdays, 4-5pm
Makerspace (directions here, check in at the front desk)

Workshop and Q&A
Wednesdays, 1-2pm
Design Hub (TEAM Lab Atrium, ask at check-out window)

Bookable One-on-One sessions
Thursdays 2-4
Design Hub (TEAM Lab Atrium, ask at check-out window)

Book a 1/2 hr session

CAD Tutorials

Just getting started with CAD or want to level up? Explore these tutorials:

CAD Fundamentals

CAD is slow

CAD is used to develop an idea once hand sketching stops being useful. (Don’t shortchange the sketching phase. CAD is slow and once you start modeling you often reduce the number of options you are considering. Doing that too early may set you on the wrong path.)

 

CAD is a means to an end

The CAD tool you choose is often interchangeable since the final output is something like a PDF (machining drawing or laser cutter) or an STL file (3D printer).

 

CAD is Hierarchical

There are many hierarchical relationships you will encounter in CAD. You often need to create reference geometry before you create functional geometry. A few of the key hierarchies include:

Make a Plane or Surface and then use it to draw a Sketch

Use your Sketch to create a Feature (like a cut or an extrusion)

Create Parts and then put them together into an Assembly

Create and accurately dimension Parts or Assembly and then add them to a Drawing

 

CAD can capture Design Intent

A good CAD model and drawing will properly convey design intent, “the intelligence built into the solid model to control the behavior of the part when subjected to changes or alteration” (such as changing a dimension). Here’s one example for how you create and dimension a hole in a block. The hole can be a certain distance from a corner or edge, or it can be in the middle of the face, for example. If the size of the block or the hole changes, the part rebuilds correctly if the design intent has been considered in the definition.

Parametric modelers (like SolidWorks and Onshape) capture the intent of a design, including relations, parameters, and model behavior. You can draw lines approximately, and later dimension them exactly. You can also change the sketch and feature dimensions at any time and rebuild the part.

In this example, one hole is fixed, one is driven by an equation, and the other two are mirrored. As the size of the hinge changes, the holes remain properly spaced along the length and width.

How will it be made?

As you design a part and assembly, you can consider how it will be made and create relationships and dimensioning schemes that communicate the manufacturing approach.

Initial Setup

  • Orient your part the way it makes sense in the world
  • Use the origin and the starting planes

This sewing machine sits on a table. Consider using the table surface as the Top plane. You typically approach the long side of the sewing machine, so the Front would go through the long dimension of the sewing machine

Start from the ground up

  • Build a strong foundation of reference geometry (Planes, surfaces, curves, axes and sketches)
  • Avoid referencing edges and features that will change frequently when dimensioning or adding relations. Use those initial planes, surfaces, curves and sketches to drive the rest of the design.

Minimize Features

Use symmetry and patterning whenever you can

Revolve instead of extrude round things

Other stuff

  • Know when to start your model over. When you iterate over and over, your model tree gets full of junk. Now that your design is solidified, you should be able to quickly model it from scratch.
  • If you are designing an injection molded part, you will need drafts and rounds (fillets) to help with the molding process. Add these features at the end of your model tree to simplify the modeling.

Onshape has an amazing learning platform. Look there first to get unstuck or add to your skillset.

Here’s your OnRamp to OnShape:

Onshape Learning: CAD Basics

 

Sheet metal modeling is awesome for anything you bend or fold including soft goods:

Onshape Learning: Sheet Metal

 

Want to level up? Surfacing gives you freedom and lets you model organic shapes like car bodies or computer mice:

Onshape Learning: Surfacing

 

Virtual simulation (FEA, CFD, etc) is one way to “prototype” your design.

Onshape Learning: Simulation

 

The best way to learn CAD is by using it for your own project. At our workshops we use the Design Hub Bambu 3D printer to make keychains / backpack hangers you design. Come to a workshop or just design your own.

Our criteria:

  • Your design should have at least two parts so you can think about the relationship between two bodies, figure out how to provide the proper clearance and once you build it, see what is working and what isn’t so you can iterate.
  • Uses this steel cable key ring (provided). The cable is 2 mm in cross-section diameter.

  • Here are a couple examples (fidget and a detachable spork)

  • Once you have your design, download Bambu Studio here. Setup your plate, slice it, and export the plate to a *.gcode.3mf file.
  • Put that file on a mini SD card, insert it into the Bambu, go to files, select your file and hit print.