Introduction to 3D CAD (with Fusion 360)

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(Generally, this workshop is offered at least once a week on a rotating basis. Check the Lab calendar for up-to-date availability!)

Fusion 360 is a Computer-aided design software package. It is parametric, which means that you can always go back and change parameters and the entire design will update to match. This wiki page is in no way exhaustive, therefore be sure to check out the help button in the top right of the Fusion 360

Typical workflow

Create a pencil and paper drawing of your idea.

  1. Create a sketch
  2. Extrude the sketch into a body
  3. Modify the resulting body
  4. (Rinse and repeat)
  5. Export

Creating a sketch

Create a Normal Sketch Plane

Press the Create Sketch button in the top left of the tool bar. Then select the plane on which you would like to create a sketch. If there are no components to select a plane from, you must select a plane from the 3D space (X plane, Y plane, Z plane). It may be helpful to choose the initial orientation that best suits your preferences and your project. For example, if the component is relatively long and flat, it may be useful to start on the Z plane. In this scenario, you will create the sketch of the bottom or top surface.

Example of Sketch Planes

If you'd like to create a sketch from a component that already exists, press the Create Sketch button and select the surface of the component you'd like to make a sketch plane from. The surface will be highlighted a light yellow color. Sketch planes must be created from a 2D plane. In other words, the surface you choose must be flat if you do not create additional planes. To see advanced information about planes, see the appropriate Wiki page.

Drawing

Lines

Perhaps as a starting exercise, create a simple shape on your newly made sketch plane. There are four main ways of selecting the line tool.

  1. Press the L key
  2. Click the line icon in the tool bar.
  3. Select line from the SKETCH drop down menu in the tool bar.
  4. Right click on a sketch to access the option wheel, then hover over sketch and then line with the mouse.

Select the line tool and draw a simple line. By default, you can see that the units are millimeters. Additionally, the dimension box is highlighted so any number typed while making the line changes the dimension instantly. Type in "5 in" and see what happens.
Fusion 360 interprets the inches as a unit of distance and converts it into millimeters. Although it is advised to use the metric system for ease of calculations, make sure you consider the tools you are using as well as any other software before making a definite decision on measurement units. Make a 100 mm x 100mm in square with these lines. Notice that the surface grid is also measured in mm. Also note that every left click creates a new line segment. To stop, either create a completed shape (denoted by an orange-colored fill) or right click and select Cancel on the option wheel.

If you started your square from the origin (0,0 on the sketch plane), you will notice that the two lines touching the origin are constrained (denoted by a black color). Conversely, the two lines not touching the origin are not constrained (denoted by a blue color). Constraints are characteristics of your sketch objects that limit movement and change. For example, if I give a line a vertical constraint, no further actions will change the orientation of that line. It will remain vertical. Logically, a sketch or shape is fully constrained when there can be no movement in the 2D space from further actions. Any attempt to move the sketch will move the entirety as long as it is not constrained to the origin. In order to learn the specifics of constraints it is recommended to play around with the sketch palette. It is a bar that appears on the right side of the screen and can be collapsed. All of the options on the sketch palette lock a characteristic of a line, point, angle, curve, or circle and help make drawing in Fusion much easier. You can make a line parallel, equal, or perpendicular to another. You can make a line horizontal to the origin or vertical, or make a point coincident (lie on top of) another point, as well as other constraints.

Specifying Dimensions

In order to change the dimension of a sketch curve, press D and then click on the line (or two lines to measure the space between) you want to size. Note that this adds a specific size constraint not shown in the sketch palette. You can input a dimension in a few different ways.

  1. Enter another dimension in the form of d1 or d2 to make a dependent dimension
  2. Enter a math expression
  3. Enter a number


In order to complete a sketch, click the "Stop Sketch" button on the tool bar.

Stop Sketch Button

Extruding a sketch

  1. Select sketch
  2. Select parameters
  3. Finish

Modifying bodies

  1. Fillets/chamfers
  2. Combining bodies

Exporting

  1. Select object
  2. Select destination
  3. Export

In order to 3D print your design, the file must ideally be saved as an STL file. STL was not originally an acronym (several backronyms have been formed), although it is a shorthand for stereo-lithography CAD (computer assisted design). The STL file converts the design into a huge amount of tiny triangles. For more information visit the wikipedia page on STL files.

To save the design as a STL file, you can press the icon in the toolbar representing a 3D printer, above MAKE. After pressing the icon, the settings window pops up. It is recommended you keep the refinement HIGH and you do not send the file to any printing utility. Simply click OK and then determine where you want the file to be saved.

Terminology

  • Curve: 2D feature (line, spline, et al.) in a Sketch. A Closed Curve is one whose start and end points are at the same spot.
  • Profile: 2D shape (circle, polygon, et al. created by a complete set of curves in a Sketch
  • Path: 3D Curve
  • Face: 3D Profile
  • Body: 3D shape comprised of Faces and Edges
  • Edge: 3D Path created by intersections of Faces
  • Surface: a Face that need not be flat
  • Sketch: digital drawing consisting of Curves.

Other Sources