Introduction

FreeCAD is a free and open-source 3D computer-aided design (CAD) software that offers a wide range of features and tools for creating and editing 3D models. One of the most powerful features of FreeCAD is its ability to create parametric 3D models, which allows users to define a model’s shape and properties using mathematical equations and relationships. In this blog post, we will explore the basics of parametric modeling in FreeCAD and provide a step-by-step guide on how to create parametric 3D models.

Getting Started with Parametric Modeling in FreeCAD

Before we dive into the process of creating parametric 3D models, it’s essential to understand the basics of parametric modeling. Parametric modeling is a way of creating 3D models that are defined by a set of parameters or variables. These parameters can be used to define the shape, size, and properties of the model, and can be easily modified to create different variations of the model.

To get started with parametric modeling in FreeCAD, you’ll need to have a basic understanding of the software and its interface. FreeCAD has a steep learning curve, but don’t worry, we’ll take it one step at a time.

Setting Up FreeCAD for Parametric Modeling

To start creating parametric 3D models in FreeCAD, you’ll need to set up the software to use the parametric modeling feature. Here’s how to do it:

• Open FreeCAD and create a new document by clicking on the “File” menu and selecting “New Document”.
• Once the document is created, click on the “Part” workbench in the left-hand menu. The Part workbench is where you’ll find the parametric modeling tools.
• In the Part workbench, click on the “Parametric” tab to access the parametric modeling tools.

Creating a Basic Parametric Model

Now that we’ve set up FreeCAD for parametric modeling, let’s create a basic parametric model. We’ll create a simple cube with a parameter that controls its size.

Creating the Cube

To create the cube, follow these steps:

• In the Part workbench, click on the “Box” tool to create a new box.
• In the “Properties” panel, click on the “Size” tab to access the size parameters.
• In the “Size” tab, set the “Length”, “Width”, and “Height” parameters to a value of 10 mm.
• Click on the “OK” button to create the cube.

Adding a Parameter to the Cube

Now that we’ve created the cube, let’s add a parameter to control its size. We’ll use the “Expression” tool to create a new parameter.

• In the Part workbench, click on the “Expression” tool to create a new expression.
• In the “Expression” dialog box, click on the “Add” button to create a new parameter.
• In the “Parameter” dialog box, set the “Name” field to “size” and the “Value” field to 10 mm.
• Click on the “OK” button to create the parameter.

Creating a Parametric Relationship

Now that we’ve created the parameter, let’s create a parametric relationship between the cube and the parameter. We’ll use the “Link” tool to create a link between the cube and the parameter.

• In the Part workbench, click on the “Link” tool to create a new link.
• In the “Link” dialog box, select the cube as the “Object” and the “size” parameter as the “Property”.
• Click on the “OK” button to create the link.

Modifying the Parametric Model

Now that we’ve created a basic parametric model, let’s modify it to see how the parametric relationship works. We’ll change the value of the “size” parameter to see how it affects the cube.

• In the Part workbench, click on the “Expression” tool to edit the “size” parameter.
• In the “Expression” dialog box, change the value of the “size” parameter to 20 mm.
• Click on the “OK” button to update the parameter.
• The cube will update automatically to reflect the new size.

Creating a More Complex Parametric Model

Now that we’ve mastered the basics of parametric modeling, let’s create a more complex parametric model. We’ll create a parametric model of a car with a parameter that controls its size.

Creating the Car Body

To create the car body, follow these steps:

• In the Part workbench, click on the “Part” tool to create a new part.
• In the “Part” dialog box, click on the “Shape” tab to access the shape parameters.
• In the “Shape” tab, select the “Parametric” tab to access the parametric shape tools.
• In the “Parametric” tab, click on the “Box” tool to create a new box.
• In the “Properties” panel, click on the “Size” tab to access the size parameters.
• In the “Size” tab, set the “Length”, “Width”, and “Height” parameters to a value of 10 mm.
• Click on the “OK” button to create the box.

Adding Parameters to the Car Body

Now that we’ve created the car body, let’s add parameters to control its size and shape. We’ll use the “Expression” tool to create new parameters.

• In the Part workbench, click on the “Expression” tool to create a new expression.
• In the “Expression” dialog box, click on the “Add” button to create a new parameter.
• In the “Parameter” dialog box, set the “Name” field to “size” and the “Value” field to 10 mm.
• Click on the “OK” button to create the parameter.
• In the Part workbench, click on the “Expression” tool to create another new expression.
• In the “Expression” dialog box, click on the “Add” button to create another new parameter.
• In the “Parameter” dialog box, set the “Name” field to “width” and the “Value” field to 5 mm.
• Click on the “OK” button to create the parameter.

Creating a Parametric Relationship for the Car Body

Now that we’ve created the parameters, let’s create a parametric relationship between the car body and the parameters. We’ll use the “Link” tool to create links between the car body and the parameters.

• In the Part workbench, click on the “Link” tool to create a new link.
• In the “Link” dialog box, select the car body as the “Object” and the “size” parameter as the “Property”.
• Click on the “OK” button to create the link.
• In the Part workbench, click on the “Link” tool to create another new link.
• In the “Link” dialog box, select the car body as the “Object” and the “width” parameter as the “Property”.
• Click on the “OK” button to create the link.

Conclusion

In this blog post, we’ve explored the basics of parametric modeling in FreeCAD and provided a step-by-step guide on how to create parametric 3D models. We’ve covered the basics of parametric modeling, including how to create a basic parametric model, modify it, and create a more complex parametric model.

FAQ

What is parametric modeling?

Parametric modeling is a way of creating 3D models that are defined by a set of parameters or variables. These parameters can be used to define the shape, size, and properties of the model, and can be easily modified to create different variations of the model.

What is FreeCAD?

FreeCAD is a free and open-source 3D computer-aided design (CAD) software that offers a wide range of features and tools for creating and editing 3D models.

How do I create a parametric model in FreeCAD?

To create a parametric model in FreeCAD, you’ll need to set up the software to use the parametric modeling feature. This involves creating a new document, selecting the Part workbench, and clicking on the “Parametric” tab to access the parametric modeling tools.

Can I use FreeCAD for other types of modeling?

Yes, FreeCAD is a versatile CAD software that can be used for a wide range of modeling tasks, including parametric modeling, freeform modeling, and 2D drafting.

What is the difference between parametric and freeform modeling?

Parametric modeling is a type of modeling that is defined by a set of parameters or variables, while freeform modeling is a type of modeling that is defined by a set of geometric shapes and surfaces.

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