CAD software is simple and does not require much effort to start with basic modeling. In this article I will explain the basic principles of CAD modeling and will make a simple model in freeware CAD (called FreeCAD).
About free CAD software.
Good news is that these days you don’t need buying CAD software license to start working with it. Simple CAD freeware would suite basic tasks and can help you getting familiar with basic modeling techniques. As soon as you feel that you need something more advanced, you can try some mid-market commercial packages. Most of them have a trial period and, if you are already a confident CAD user, this period is enough for deciding whether the software suits you.
Each software has its “specialization” and does certain things better. Also interface can be intuitive for people who do 3D design or for 2D CAD users. Consider the following software packages:
- Free CAD
Because of background in parametric modeling and Mechanical engineering I found it easier to use “FreeCAD”.
Typical modeling workflow.
1. Create a base body with one of basic operations. It can be extruded/revolved body or a primitives like block, sphere, cone, etc.
2. Create smaller details of the model and unite with or subtract from the base
3. When needed, make patterns of features
4. In the end add minor details like fillets, chamfers, etc.
5. Forward the model to the next stage (like drafting, export for 3D printing, assembly modeling)
Step-by-step instructions for FreeCAD
- Create new part
Create first sketch and “base body”
- Create new file
- Select Part Design workbench
- Select a plane, for example XY
- Draw a sketch geometry for the main body using polyline, make sure you automatically set vertical and horizontal constrains
- Add required constraints
- Select two points and add coincident constraint
- Select the line and add horisontal constraint
- Add dimensions:
- Select the line
- Choose dimension type
- Finish adding the dimensions
- Press Close for sketch
- To create rotation geometry choose Revolve a selected sketch
Add detailed features
- Select the bottom surface of the body
- Create a new sketch (sketch is now connected to surface)
- Draw geometry and dimensions as shown
- Close the sketch
- Choose Create pocket with selected sketch
- Choose Up to Face and define the top face
- Choose Pocket in the model tree
- Choose Select polar pattern
- Set occurrences to four
- Press OK
Add minor details
- Finnish up by adding fillets, chamfers
- Select the edge (multiple selection can be done with Ctrl)
- Choose Fillet or Chamfer
- Enter the size
- Press OK
Forward the model further
In this example model is forwarded for 3D printing
- Choose the model (last element in the model tree)
- Choose File, Export
- Select Mech formats as type
- Enter name with required extension
The instruction shows most of the features, required for simple parts in mechanical engineering. It can help understanding CAD basics in relatively short time period.
Do you use any Free CAD software? How did you start using it?