FreeCAD CAD CAM: Your Free Guide

Introduction to FreeCAD for CAD CAM

Okay, guys, let's dive into the amazing world of FreeCAD and how it's a total game-changer for both CAD (Computer-Aided Design) and CAM (Computer-Aided Manufacturing). FreeCAD is this awesome open-source software that lets you design and create 3D models. What's super cool is that it's free—yes, you heard that right, totally free!—which makes it accessible to everyone, from hobbyists tinkering in their garages to professional engineers needing powerful design tools without the hefty price tag. When we talk about CAD, we mean using software to create detailed 2D or 3D models of physical parts or products. This is crucial for visualizing and planning your projects before you even think about building them. CAM, on the other hand, takes those designs and prepares them for manufacturing, often using CNC (Computer Numerical Control) machines. This involves creating toolpaths, which tell the machines exactly how to cut, drill, or shape the material to match your design. FreeCAD bridges this gap beautifully, allowing you to design your parts and then prepare them for manufacturing all in one place. It supports a wide range of file formats, so you can easily import and export designs from other CAD software. Plus, with its modular architecture, you can add extra functionality through plugins and extensions, tailoring it to your specific needs. Whether you're designing a simple bracket, a complex mechanical assembly, or even artistic sculptures, FreeCAD provides a robust and versatile platform to bring your ideas to life. And the best part? The active community around FreeCAD means there's always help and support available, making it easy to learn and master this incredible tool.

Setting Up FreeCAD for CAD CAM Projects

So, you're ready to get started with FreeCAD CAD CAM projects? Awesome! The first step is setting up FreeCAD correctly to ensure a smooth and efficient workflow. First things first, head over to the FreeCAD website and download the latest stable version for your operating system (Windows, macOS, or Linux). Installation is pretty straightforward – just follow the prompts. Once you've got FreeCAD installed, it's a good idea to tweak a few settings to optimize it for your specific needs. Go to the 'Edit' menu, then 'Preferences.' Here, you can customize everything from the interface language and theme to the units of measurement and default file locations. For CAD CAM work, I recommend setting the default units to millimeters or inches, depending on your typical projects. Next, let’s talk about workbenches. FreeCAD uses a modular system called workbenches, each designed for specific tasks. The 'Part Design' workbench is essential for creating solid models, while the 'Sketcher' workbench is perfect for creating 2D profiles that you can then extrude or revolve into 3D shapes. The 'Path' workbench is where the magic happens for CAM – it allows you to generate toolpaths for CNC machines. Make sure these workbenches are enabled. You can also explore and install additional workbenches through the Addon Manager (under the 'Tools' menu). These addons can extend FreeCAD's functionality, adding support for specialized tasks like architectural design, FEM analysis, or even more advanced CAM operations. Finally, don't forget to configure your mouse and keyboard shortcuts. FreeCAD allows you to customize these to match your preferences, making it faster and more intuitive to navigate the interface and perform common tasks. With these initial settings configured, you'll be well-prepared to tackle your first CAD CAM projects in FreeCAD.

Designing with FreeCAD: A CAD Workflow

Alright, let's get into the nitty-gritty of designing with FreeCAD. Your CAD workflow in FreeCAD will typically start with creating a 2D sketch. Open the 'Sketcher' workbench and create a new sketch on one of the planes (XY, XZ, or YZ). Use the various tools available to draw the basic shape of your part. Don't worry too much about precision at this stage; just get the overall form down. Next, you'll want to add constraints to your sketch. Constraints are rules that define the relationships between different elements of your sketch, such as making lines parallel, perpendicular, or equal in length. Applying constraints ensures that your design remains consistent and predictable, even when you make changes. The 'Sketcher' workbench provides a range of constraints, including dimensional constraints (defining lengths and distances) and geometric constraints (defining relationships between lines and curves). Once your sketch is fully constrained (meaning it's fully defined and cannot be accidentally altered), you can exit the 'Sketcher' workbench and switch to the 'Part Design' workbench. From here, you can use features like 'Pad' (extrude), 'Revolve,' or 'Pocket' to create 3D solids from your 2D sketch. The 'Pad' feature, for example, takes your sketch and extrudes it along a specified direction, creating a solid with a defined thickness. The 'Revolve' feature rotates your sketch around an axis, creating a circular solid. The 'Pocket' feature removes material from an existing solid, allowing you to create holes or cavities. As you build your 3D model, you can use Boolean operations (like 'Union,' 'Difference,' and 'Intersection') to combine or subtract different solids, creating complex shapes. You can also add fillets (rounded edges) and chamfers (beveled edges) to improve the appearance and functionality of your design. Remember to save your work frequently! FreeCAD supports a variety of file formats, but the native format is .FCStd. Regularly saving your design ensures that you don't lose any progress in case of a crash or unexpected interruption. By following this workflow, you can efficiently create detailed and accurate 3D models in FreeCAD, laying the foundation for your CAM operations.

CAM with FreeCAD: Preparing for Manufacturing

Now that you've got your 3D model designed in FreeCAD, it's time to prepare it for manufacturing using the CAM capabilities. This is where the 'Path' workbench comes into play. The 'Path' workbench allows you to generate toolpaths that CNC machines can follow to cut, drill, or shape your part from a raw material. The first step is to create a 'Job.' A Job in the 'Path' workbench defines the overall manufacturing process, including the stock material, the cutting tools, and the coordinate system. You'll need to specify the dimensions and position of your stock material, as well as the type and size of the cutting tools you'll be using. Next, you'll start creating operations. Operations are specific machining steps, such as facing, profiling, pocketing, or drilling. Each operation requires you to select the geometry you want to machine, as well as the cutting parameters, such as the feed rate, spindle speed, and depth of cut. FreeCAD provides a variety of operation types, each optimized for different machining tasks. The 'Profile' operation, for example, is used to cut around the outside of a part, while the 'Pocket' operation is used to remove material from the inside of a closed shape. The 'Drilling' operation is used to create holes. As you create operations, FreeCAD generates toolpaths that visualize the movements of the cutting tool. You can simulate these toolpaths to check for collisions or other issues before you send the code to your CNC machine. Once you're satisfied with your toolpaths, you can export them as G-code. G-code is a programming language that CNC machines understand. FreeCAD allows you to customize the G-code output to match the specific requirements of your machine. Before running the G-code on your CNC machine, it's always a good idea to double-check it in a G-code simulator. This helps you catch any potential errors or issues before they cause damage to your machine or workpiece. With a little practice, you'll be able to use FreeCAD's CAM capabilities to efficiently and accurately prepare your designs for manufacturing.

FreeCAD vs. Other CAD CAM Software

Okay, so you might be wondering how FreeCAD stacks up against other CAD CAM software out there. That's a fair question! One of the biggest advantages of FreeCAD is, of course, its price – it's completely free! This makes it an excellent choice for hobbyists, students, and small businesses who can't afford expensive commercial software like SolidWorks or Autodesk Inventor. But don't let the price fool you; FreeCAD is still a powerful and capable tool. While it may not have all the bells and whistles of some of the more expensive packages, it offers a solid set of features for both CAD and CAM. In terms of CAD, FreeCAD supports parametric modeling, which means you can easily modify your designs by changing parameters like dimensions or angles. It also supports a wide range of file formats, so you can easily import and export designs from other software. For CAM, FreeCAD's 'Path' workbench allows you to generate toolpaths for CNC machines. While it may not be as advanced as dedicated CAM software like Mastercam, it's perfectly adequate for many machining tasks. One area where FreeCAD shines is its extensibility. Thanks to its modular architecture, you can add extra functionality through plugins and extensions. This allows you to customize FreeCAD to meet your specific needs. Another advantage of FreeCAD is its active community. There's a large and helpful community of users who are always willing to answer questions and provide support. This can be a huge asset when you're learning the software or troubleshooting issues. Of course, FreeCAD does have some limitations. It can be a bit more challenging to learn than some other CAD software, and its user interface may not be as polished. However, with a little patience and practice, you can definitely master FreeCAD and use it to create amazing designs and prepare them for manufacturing. Overall, FreeCAD is a great option for anyone looking for a free and open-source CAD CAM solution. It may not be the most powerful or feature-rich software out there, but it's a capable tool that can handle a wide range of tasks.

Advanced Techniques in FreeCAD CAD

Once you've mastered the basics of FreeCAD CAD, it's time to dive into some advanced techniques to take your designs to the next level. One such technique is using expressions. Expressions allow you to create relationships between different parameters in your model, so that when one parameter changes, others update automatically. This can be incredibly useful for creating parametric designs that are easy to modify and adapt. For example, you could use an expression to define the length of a part as a multiple of its width, so that when you change the width, the length updates automatically. Another advanced technique is using macros. Macros are essentially scripts that automate repetitive tasks. If you find yourself performing the same series of actions over and over again, you can create a macro to automate them. FreeCAD comes with a built-in macro recorder that makes it easy to create macros. You can also write your own macros using Python scripting. Python scripting is a powerful way to extend FreeCAD's functionality and customize it to your specific needs. You can use Python to create custom tools, automate complex operations, and even develop entire workbenches. Another advanced technique is using external workbenches. As mentioned earlier, FreeCAD has a modular architecture that allows you to add extra functionality through plugins and extensions. Many of these extensions are packaged as external workbenches. There are external workbenches available for a wide range of tasks, such as architectural design, FEM analysis, and even more advanced CAM operations. Finally, don't underestimate the power of the Assembly workbench. While FreeCAD's assembly capabilities aren't as advanced as some dedicated assembly software, they're perfectly adequate for many tasks. You can use the Assembly workbench to create assemblies of multiple parts, define constraints between them, and simulate their motion. By mastering these advanced techniques, you can unlock the full potential of FreeCAD and create truly impressive designs.

Optimizing FreeCAD for CAM Operations

To really get the most out of FreeCAD for CAM operations, you'll want to optimize your setup and workflow. One key area to focus on is tool management. The 'Path' workbench in FreeCAD allows you to create and manage a library of cutting tools. You should take the time to define your tools accurately, including their geometry, material, and cutting parameters. This will help FreeCAD generate more accurate and efficient toolpaths. Another important optimization is to carefully consider your machining strategies. FreeCAD offers a variety of operation types, each optimized for different machining tasks. You should choose the operation type that is best suited for the geometry you want to machine and the material you're working with. For example, the 'Profile' operation is ideal for cutting around the outside of a part, while the 'Pocket' operation is better suited for removing material from the inside of a closed shape. You should also experiment with different cutting parameters, such as feed rate, spindle speed, and depth of cut, to find the optimal settings for your machine and material. Another way to optimize your CAM operations is to use stock models. A stock model is a 3D representation of the raw material you're starting with. By defining a stock model in FreeCAD, you can help the software generate more efficient toolpaths and avoid unnecessary cuts. You can also use stock models to simulate the machining process and check for collisions or other issues. Finally, don't forget to post-process your G-code. The G-code generated by FreeCAD may need to be tweaked to match the specific requirements of your CNC machine. You can use a G-code editor to make these adjustments. By optimizing your setup and workflow, you can significantly improve the efficiency and accuracy of your CAM operations in FreeCAD.

Troubleshooting Common FreeCAD CAD CAM Issues

Even with the best setup and workflow, you're bound to run into some issues when working with FreeCAD CAD CAM. Here are some common problems and how to troubleshoot them:

1. Sketcher Constraints Not Solving: This is a common issue, especially for beginners. If your sketch is over-constrained (meaning there are too many conflicting constraints), FreeCAD may not be able to solve it. Try removing some of the constraints to see if that helps. Also, make sure that your sketch is not under-constrained (meaning it's not fully defined). Add more constraints until the sketch is fully constrained.

2. Toolpath Generation Errors: If FreeCAD is unable to generate a toolpath, there could be several reasons. First, check that your geometry is valid and that there are no gaps or overlaps. Second, make sure that your cutting tool is appropriate for the geometry you're trying to machine. Third, try adjusting the cutting parameters, such as the stepover or stepdown.

3. G-Code Not Working on CNC Machine: If the G-code generated by FreeCAD doesn't work on your CNC machine, there could be several reasons. First, make sure that the post-processor you're using is compatible with your machine. Second, check that the G-code syntax is correct. Third, try adjusting the machine settings in FreeCAD to match your machine's configuration.

4. FreeCAD Crashing: If FreeCAD is crashing frequently, there could be several reasons. First, make sure that you have the latest version of FreeCAD installed. Second, try disabling any external workbenches or macros that you're not using. Third, check that your computer meets the minimum system requirements for FreeCAD.

5. Slow Performance: If FreeCAD is running slowly, there are several things you can try to improve performance. First, close any unnecessary applications. Second, increase the amount of memory allocated to FreeCAD. Third, simplify your model by reducing the number of features or faces. By following these troubleshooting tips, you can overcome many of the common issues you'll encounter when working with FreeCAD CAD CAM.

FreeCAD for 3D Printing: A Complete Guide

FreeCAD is not just for CAD CAM; it's also an excellent tool for preparing models for 3D printing. To get started, you'll need to ensure your 3D model is manifold, meaning it's a closed, watertight solid. This is crucial for 3D printing, as the slicer software needs to understand the inside and outside of your model. In the 'Part' workbench, use the 'Check Geometry' tool to identify any issues like open edges or faces. Repair these issues before proceeding. Once your model is manifold, export it as an STL file. STL (Stereolithography) is the standard file format for 3D printing. You can adjust the resolution of the STL file during export. Higher resolution results in a more detailed model but also a larger file size. A good balance is usually sufficient for most prints. Next, you'll need to use a slicer software like Cura, PrusaSlicer, or Simplify3D. Import the STL file into the slicer. The slicer software will convert your 3D model into a series of layers that the 3D printer can understand. In the slicer, you'll need to configure various settings, such as layer height, infill density, print speed, and support structures. Layer height determines the resolution of your print – lower layer heights result in smoother surfaces but longer print times. Infill density affects the strength and weight of your print – higher infill densities result in stronger but heavier prints. Print speed affects the overall print time – slower speeds generally result in higher quality prints. Support structures are needed for overhangs or complex geometries to prevent them from collapsing during printing. Once you've configured the slicer settings, generate the G-code file. This file contains the instructions that your 3D printer will follow to create your model. Finally, transfer the G-code file to your 3D printer and start printing! Keep an eye on the print during the first few layers to ensure everything is going smoothly. By following these steps, you can use FreeCAD to design and prepare models for 3D printing with excellent results.

Integrating FreeCAD with CNC Machines

Integrating FreeCAD with your CNC machine is essential for bringing your designs to life. After generating G-code in the 'Path' workbench, the next step is to transfer it to your CNC machine. This is typically done using a USB drive or a direct connection between your computer and the CNC controller. The specific method will depend on your machine's capabilities. Before running the G-code, it's crucial to set up your CNC machine correctly. This involves setting the work coordinate system (WCS), which defines the origin point for your machining operations. You'll also need to load the appropriate cutting tools into the machine and calibrate their lengths. The WCS should match the coordinate system you used in FreeCAD when generating the toolpaths. If the coordinate systems don't align, your part will be machined in the wrong location. Once the machine is set up, you can load the G-code file into the CNC controller. Most CNC controllers have a built-in G-code editor that allows you to review the code and make any necessary adjustments. Before starting the machining process, it's always a good idea to run a dry run (also known as an air cut). This involves running the G-code without any material in the machine to check for collisions or other issues. Watch the machine carefully during the dry run to make sure the toolpaths are correct and that the machine is moving as expected. If everything looks good, you can then load the material into the machine and start machining. Monitor the machining process closely, especially during the first few passes. Listen for any unusual noises or vibrations, and watch for any signs of tool wear or breakage. If you encounter any problems, stop the machine immediately and investigate the cause. By carefully integrating FreeCAD with your CNC machine, you can create accurate and high-quality parts from your designs.

Mastering Parametric Modeling in FreeCAD

Parametric modeling is a powerful technique in FreeCAD that allows you to create designs that can be easily modified and adapted. In parametric modeling, you define the geometry of your model using parameters, such as dimensions, angles, and relationships. When you change a parameter, the entire model updates automatically. To master parametric modeling in FreeCAD, start by using the 'Sketcher' workbench to create 2D sketches. Constrain your sketches using dimensional and geometric constraints. Dimensional constraints define the size of elements, while geometric constraints define the relationships between them (e.g., parallel, perpendicular, tangent). Use expressions to create relationships between parameters. Expressions allow you to define one parameter in terms of another. For example, you could define the length of a part as a multiple of its width. When you change the width, the length updates automatically. You can access the expression editor by right-clicking on a dimension in the 'Sketcher' workbench and selecting 'Properties.' In the 'Properties' panel, you can enter an expression in the 'Value' field. Use named parameters to make your models more readable and maintainable. Named parameters allow you to assign meaningful names to dimensions and other values. This makes it easier to understand the purpose of each parameter and how it affects the model. You can create named parameters by using the 'Create Alias' tool in the 'Sketcher' workbench. Use spreadsheets to manage complex parameters. Spreadsheets provide a convenient way to organize and manage large numbers of parameters. You can create a spreadsheet in FreeCAD and link its cells to dimensions and other values in your model. This makes it easy to change multiple parameters at once and see how they affect the model. By mastering parametric modeling techniques, you can create designs that are flexible, adaptable, and easy to maintain in FreeCAD.

Creating Assemblies in FreeCAD: A Step-by-Step Guide

Creating assemblies in FreeCAD involves combining multiple parts into a single model. This is essential for designing complex products or machines. FreeCAD's assembly capabilities are primarily handled through external workbenches like Assembly3 or A2plus, which offer more advanced features than the built-in assembly tools. First, install an assembly workbench. Go to 'Tools' -> 'Addon Manager' and search for 'Assembly3' or 'A2plus.' Install your preferred workbench and restart FreeCAD. Import your individual parts into a new FreeCAD document. You can either import existing part files or create new parts directly in the document. Position the parts using constraints. Assembly workbenches use constraints to define the relationships between parts. Common constraints include:

• Fixed: Fixes a part in space.
• Coincident: Aligns two faces or edges.
• Distance: Specifies the distance between two faces or edges.
• Angle: Specifies the angle between two faces or edges.

Add constraints one by one to define the desired relationships between the parts. Start with the most important constraints and gradually add more constraints until the assembly is fully defined. Use the assembly tree to manage the assembly. The assembly tree shows the hierarchy of parts and constraints in your assembly. You can use the assembly tree to select parts, add constraints, and modify the assembly structure. Check for interferences. Once you've created the assembly, check for interferences between the parts. Interferences occur when two parts occupy the same space. FreeCAD provides tools for detecting and resolving interferences. Update the assembly. After making changes to the parts or constraints, update the assembly to reflect the changes. The assembly workbench will automatically recalculate the positions of the parts based on the new constraints. By following these steps, you can create complex assemblies in FreeCAD using external assembly workbenches.

Simulating CNC Toolpaths in FreeCAD

Simulating CNC toolpaths in FreeCAD is crucial for verifying your CAM operations and preventing costly mistakes. FreeCAD's 'Path' workbench provides a built-in simulation tool that allows you to visualize the toolpaths and check for collisions or other issues. To simulate a toolpath, first, generate the toolpath in the 'Path' workbench. Select the 'Simulate' command from the 'Path' menu. The simulation window will open, showing a 3D representation of your part, the cutting tool, and the toolpath. Use the simulation controls to control the simulation speed and view. You can pause, resume, rewind, and fast-forward the simulation. Watch the simulation carefully to check for collisions between the cutting tool and the part, the stock material, or the machine fixtures. Collisions can damage the cutting tool, the part, or the machine. Check for excessive material removal. The simulation can show you how much material is being removed by each toolpath. If you see that too much material is being removed in a single pass, you may need to adjust the cutting parameters, such as the depth of cut or the stepover. Check for sharp corners or sudden changes in direction. Sharp corners or sudden changes in direction can cause the cutting tool to vibrate or break. If you see any sharp corners or sudden changes in direction, you may need to adjust the toolpath to smooth them out. Use the measurement tool to measure distances and angles in the simulation. This can be helpful for verifying that the toolpath is accurate and that the part is being machined to the correct dimensions. If you find any issues during the simulation, adjust the toolpath or the cutting parameters and simulate again until you are satisfied with the results. By simulating your CNC toolpaths in FreeCAD, you can catch potential problems before they cause damage or waste material.

Using FreeCAD for Reverse Engineering

FreeCAD can be a valuable tool for reverse engineering, the process of creating a 3D model from an existing physical part. This is useful for recreating damaged parts, creating variations of existing designs, or simply understanding how a part was made. The basic workflow for reverse engineering in FreeCAD involves scanning the physical part, importing the scan data into FreeCAD, and then creating a 3D model based on the scan data. First, scan the physical part using a 3D scanner. There are many different types of 3D scanners available, ranging from handheld scanners to industrial-grade scanners. Choose a scanner that is appropriate for the size and complexity of the part you are scanning. Import the scan data into FreeCAD. FreeCAD supports several different file formats for scan data, including STL, OBJ, and PLY. Clean up the scan data. Scan data often contains noise and errors. Use FreeCAD's mesh editing tools to clean up the scan data and remove any unwanted artifacts. Create a 3D model based on the scan data. There are several different ways to create a 3D model from scan data in FreeCAD. One approach is to use the scan data as a reference for creating a parametric model. This involves creating sketches and features that match the shape of the scan data. Another approach is to create a mesh model directly from the scan data. This involves converting the scan data into a mesh object and then editing the mesh to create the desired shape. Verify the accuracy of the 3D model. Once you have created a 3D model, it is important to verify its accuracy. Compare the 3D model to the physical part and make any necessary adjustments. You can also use FreeCAD's measurement tools to measure the dimensions of the 3D model and compare them to the dimensions of the physical part. By using FreeCAD for reverse engineering, you can create accurate 3D models of existing physical parts.

FreeCAD for Architectural Design

While FreeCAD is primarily known for its mechanical design capabilities, it can also be used for architectural design. FreeCAD's Arch workbench provides a set of tools specifically designed for creating architectural models. To use FreeCAD for architectural design, start by switching to the Arch workbench. The Arch workbench provides tools for creating walls, doors, windows, roofs, and other architectural elements. Create a basic floor plan using the Wall tool. The Wall tool allows you to create walls by specifying their length, width, and height. Add doors and windows using the Door and Window tools. The Door and Window tools allow you to create doors and windows by specifying their size, position, and style. Create a roof using the Roof tool. The Roof tool allows you to create different types of roofs, such as gable roofs, hip roofs, and flat roofs. Add other architectural elements, such as stairs, columns, and beams. The Arch workbench provides tools for creating these elements as well. Use the BIM (Building Information Modeling) capabilities of FreeCAD to manage the data associated with your architectural model. BIM allows you to store information about the materials, dimensions, and properties of each element in your model. Create drawings and renderings of your architectural model. FreeCAD provides tools for creating 2D drawings and 3D renderings of your model. You can use these drawings and renderings to communicate your design to clients and contractors. Export your architectural model to other file formats, such as IFC (Industry Foundation Classes). IFC is a standard file format for exchanging BIM data between different software applications. By using FreeCAD for architectural design, you can create detailed and accurate architectural models.

Creating Custom Parts Libraries in FreeCAD

Creating custom parts libraries in FreeCAD can significantly speed up your design process. A parts library is a collection of pre-designed parts that you can easily insert into your models. This eliminates the need to create the same parts over and over again. To create a custom parts library in FreeCAD, first, create a new folder to store your parts. Choose a location that is easy to access and remember. Create individual FreeCAD files for each part in your library. Design each part carefully and save it in its own file. Use descriptive filenames for each part. This will make it easier to find the parts you need when you are working on a project. Create a FreeCAD project file to organize your parts library. This project file will contain links to all of the individual part files in your library. Use the 'Link' feature in FreeCAD to create links to the part files in your library. This will allow you to insert the parts into your models without copying the files. Add metadata to each part, such as descriptions, keywords, and thumbnail images. This will make it easier to search for and identify the parts in your library. Use the 'Parts Library' workbench to manage your parts library. This workbench provides a convenient way to browse, search, and insert parts into your models. Share your parts library with other FreeCAD users. You can share your parts library by exporting it as a ZIP file or by uploading it to a shared repository. By creating custom parts libraries in FreeCAD, you can save time and effort when designing your models.

FreeCAD Scripting with Python: An Introduction

FreeCAD's scripting capabilities, using Python, offer immense power and flexibility. With Python scripting, you can automate tasks, create custom tools, and extend FreeCAD's functionality in countless ways. To get started with FreeCAD scripting, open the FreeCAD console. The FreeCAD console is a Python interpreter that allows you to execute Python code directly within FreeCAD. You can open the console by going to 'View' -> 'Panels' -> 'Python console.' Import the FreeCAD module. The FreeCAD module provides access to FreeCAD's objects and functions. You can import the FreeCAD module by typing import FreeCAD in the console. Create a new document. You can create a new document by typing doc = FreeCAD.newDocument() in the console. Add a new part to the document. You can add a new part to the document by typing `part = FreeCAD.ActiveDocument.addObject(