Computer Aided Design lab manual FreeCad.pdf

Computer Aided Design lab (ME604P)
LIST OF EXPERIMENTS:
1. Introduction of 3D Modelling software
2. Initiating the Graphics Package; Setting the paper size, space; setting the limits, units; use of snap
and grid commands.
3. Drawing of primitives (Line, arc, circle, ellipse, triangle etc.)
4. Dimensioning the drawing and adding text.
5. Setting the layers and application of layers.
6. Isometric and Orthographic projections.
7. Viewing in three dimensions.
8. Removal of hidden lines – Shading and Rendering

Experiment 1: Introduction to 3D Modelling Software (FreeCAD)
AIM
To become familiar with FreeCAD software by exploring its interface, setting up a new project, and
creating basic 2D sketches that are transformed into 3D models using parametric tools.
REQUIREMENTS
Hardware:
 Computer with a minimum of 4GB RAM and 64-bit processor
 Graphics card compatible with OpenGL 2.0 or higher
 Screen resolution of 1920×1080 pixels or more
Software:
 FreeCAD version 0.20 or later (Windows/Linux/macOS)
 Python and OpenCascade (included with FreeCAD installation)
THEORY
FreeCAD is an open-source parametric 3D CAD software used for designing mechanical parts and
assemblies. It enables parametric modeling, which simplifies the process of editing designs by adjusting
parameters. FreeCAD supports multiple workbenches, such as Part Design, Sketcher, and Draft,
which are essential for mechanical CAD applications.
PROCEDURE
1. Launching FreeCAD
o Open FreeCAD and choose the Part Design workbench from the start screen.
2. Exploring the Interface
o Observe the layout of the interface, including the toolbar, combo view, model tree, 3D
view, and task panel.
3. Setting Preferences
o Navigate to Edit → Preferences to configure:
 Units (e.g., mm)
 Grid visibility and snapping
 Default background and color settings
o Save the preferences for future use.
4. Creating a New Document
o Create a new project using File → New.
o Save the project with an appropriate name (e.g., Basic_Model.FCStd).
5. Working with Workbenches
o Explore different workbenches:

 Sketcher for creating 2D profiles
 Part Design for creating and editing 3D models
 Draft for technical drawing functions
6. Creating 2D Sketches
o In the Sketcher workbench, select a plane (XY, XZ, or YZ).
o Use sketching tools such as:
 Line for edges
 Circle for holes
 Rectangle for base shapes
7. Converting Sketch into 3D
o Switch to the Part Design workbench.
o Select the sketch and apply the Pad (extrude) tool.
o Enter the desired length of extrusion (e.g., 20 mm).
8. Modifying the Model
o Apply basic features like fillet, chamfer, or pocket to modify the 3D object using
appropriate tools in the Part Design workbench.
9. Saving and Exporting
o Save the model using File → Save.
o Export the model in formats such as .STL or .STEP using File → Export for
compatibility with 3D printing or other software.
10. Practice Task
 As an application of the above steps, create a box with multiple holes on the top surface and
add fillets to its edges.
RESULT
By performing this experiment, the FreeCAD interface was explored, basic project settings were
configured, 2D sketches were created, extruded into 3D models, and modified using fundamental
parametric tools. The model was successfully saved and exported for further use.
CONCLUSION
This experiment provided a practical introduction to FreeCAD and its capabilities in 3D modeling. The
essential skills of navigating the interface, using sketch and part design tools, and saving/exporting
models were acquired. These foundational skills are vital for mechanical CAD applications and will be
built upon in subsequent experiments.

Experiment 2: Initiating the Graphics Package; Setting Paper Size, Space; Setting Limits, Units;
Use of Snap and Grid Commands (FreeCAD)
AIM
To understand the setup process of the FreeCAD environment by configuring the workspace, units,
limits, paper size (for drawings), and learning how to use grid and snap tools for accurate sketching.
REQUIREMENTS
Hardware:
 Computer with minimum 4GB RAM, 64-bit processor
 Graphics card supporting OpenGL 2.0 or higher
 Monitor with at least 1920×1080 resolution
Software:
 FreeCAD (version 0.20 or higher)
 Python and OpenCascade (included in FreeCAD)
THEORY
In CAD modeling, accurate dimensioning and layout are essential. FreeCAD provides options for
setting units, limits (drawing boundaries), and grid visibility for easier drawing alignment. The Snap
feature ensures precision by automatically aligning geometry to specified reference points like
endpoints, midpoints, and intersections.
Although FreeCAD is different from AutoCAD in the use of paper space and model space terminology,
its TechDraw and Draft workbenches allow setup of similar drawing templates and controls for grid
and snapping.
PROCEDURE
1. Launching FreeCAD
o Start FreeCAD and choose a workbench like Sketcher or Draft.
2. Setting Units
o Navigate to Edit → Preferences → General → Units.
o Choose appropriate unit (e.g., mm for mechanical design).
o Click OK and restart FreeCAD if required for settings to apply.
3. Setting Drawing Limits
o In the Draft workbench, use grid size to visually manage drawing boundaries.
o Limits in FreeCAD are managed by setting grid spacing and size under:
 Edit → Preferences → Draft → Grid and snapping
4. Activating Grid and Snap

o Enable grid visibility: Toggle the grid from the bottom toolbar or from Draft → Utilities
→ Toggle Grid.
o Activate snapping by selecting snap options like:
 Endpoint
 Midpoint
 Intersection
 Center
o Access snapping options from the Snap toolbar or Draft → Snap.
5. Configuring the Drawing Sheet (TechDraw Workbench)
o Switch to TechDraw workbench.
o Create a new drawing using Insert default page.
o Set paper size: Right-click on the drawing page → Change Page Size → Choose from
A4, A3, etc.
o Insert views from the model for technical documentation.
6. Setting the Workspace Appearance
o Customize background color and grid color:
o Edit → Preferences → Display → 3D View or Draft options.
o Adjust zoom and view settings for better visibility.
7. Creating a Simple Draft
o Using Draft workbench, draw simple shapes like rectangles or lines aligned with the
grid using snap tools.
o Ensure the snapping points are engaged correctly for alignment.
RESULT
The FreeCAD environment was successfully configured by setting units, enabling the snap and grid
tools, and adjusting drawing area properties. A sample drawing with correct snapping alignment and
limits was created using the Draft and TechDraw workbenches.
CONCLUSION
This experiment provided a clear understanding of how to initialize and customize the FreeCAD
workspace for precise CAD drafting. The concepts of unit configuration, snapping, grid visibility, and
drawing page setup were explored. These steps ensure an accurate and efficient modeling environment
essential for further design tasks.

Experiment 3: Drawing of Primitives (Line, Arc, Circle, Ellipse, Triangle, etc.)
AIM
To understand and practice the use of basic geometric drawing tools (primitives) in FreeCAD, such as
lines, arcs, circles, ellipses, and polygons, within the Sketcher and Draft workbenches.
REQUIREMENTS
Hardware:
 A computer with at least 4 GB RAM
 Graphics card with OpenGL 2.0 or higher
 Full HD monitor (1920×1080 resolution or higher)
Software:
 FreeCAD (version 0.20 or newer)
 Operating System: Windows, macOS, or Linux
 Pre-installed Python and OpenCascade (automatically included)
THEORY
Drawing primitives are the fundamental building blocks in CAD modeling. In FreeCAD, these elements
can be created using tools provided in the Draft or Sketcher workbench. Sketches act as profiles for 3D
modeling, while drafts can be used for 2D schematics or technical illustrations.
Understanding how to use and constrain basic geometries allows users to create accurate and parametric
models suitable for engineering design and analysis.
PROCEDURE
1. Launch FreeCAD
o Open FreeCAD and create a new document via File → New.
2. Switch to Sketcher Workbench
o Select the Sketcher workbench from the dropdown in the top toolbar.
3. Create a New Sketch
o Click on Create New Sketch.
o Select a base plane (XY, XZ, or YZ) for sketching.
4. Drawing a Line
o Click on the Line tool in the Sketcher toolbar.
o Click to set start and end points.
o Constrain the line using horizontal, vertical, or length constraints.
5. Drawing a Circle
o Click the Circle tool.

o Select center point and radius by clicking.
o Add dimensional constraint to fix the radius if required.
6. Drawing an Arc
o Choose the Arc tool (by 3 points or center and end-points).
o Click the three points: start, a point on the arc, and end point.
o Add radius and angle constraints as needed.
7. Drawing an Ellipse
o Select the Ellipse tool.
o Define the center and major axis, followed by minor axis.
o Optionally constrain lengths or axis orientation.
8. Drawing a Triangle
o Use the Polygon tool (in Draft workbench) or draw three Lines connected at endpoints
to form a triangle.
o Use Coincident constraints to join endpoints.
9. Using the Draft Workbench (Optional for Comparison)
o Switch to Draft workbench for another way of drawing primitives.
o Try drawing:
 Line, Circle, Arc, Ellipse, and Polygon.
 Observe that objects here are not parametric unless converted into sketches.
10. Constraining Geometry
 Apply constraints such as:
o Distance
o Angle
o Vertical/Horizontal alignment
o Coincidence (joining ends)
11. Close and Save the Sketch
 Once drawing is complete, click Close to exit the sketch mode.
 Save the file via File → Save.
RESULT
Basic geometric primitives such as lines, arcs, circles, ellipses, and triangles were successfully drawn
using the Sketcher and Draft workbenches. Constraints were applied where necessary to maintain
geometry control and parametric integrity.
CONCLUSION
This experiment introduced the usage of essential geometric tools in FreeCAD. Mastery of these
primitives and their constraints is crucial in creating complex models. These skills form the basis of
parametric CAD design, allowing future operations such as extrusion, revolution, and Boolean
operations in 3D modeling.

Experiment 4: Dimensioning the Drawing and Adding Text
AIM
To understand and apply dimensioning techniques and text annotations to 2D sketches in FreeCAD for
clear communication of design intent and geometry specifications.
REQUIREMENTS
Hardware:
 Full HD monitor (1920×1080 resolution or higher)
Software:
 FreeCAD (version 0.20 or newer)
 Required libraries (pre-installed with FreeCAD)
THEORY
Dimensioning is a vital part of engineering drawing, used to convey size, location, and geometric
features. In FreeCAD, dimensions are applied using constraints in the Sketcher workbench. For
presentation and documentation purposes, annotations and text are added in the TechDraw workbench.
Parametric dimensions in sketches help maintain relationships between geometric elements. Text
annotations are useful for adding descriptions, labels, or notes in the drawing.
PROCEDURE
1. Open FreeCAD and Create or Load a Sketch
o Start FreeCAD.
o Either create a new sketch or open a saved file from a previous experiment.
2. Switch to Sketcher Workbench
o Go to Sketcher workbench via the dropdown menu.
3. Apply Dimensional Constraints
o Length Constraint: Select a line and click the Length Constraint tool to set its length.
o Radius/Diameter Constraint: Select a circle or arc and apply radius/diameter as
needed.
o Horizontal/Vertical Distance: Use these constraints to define spatial distances
between points or lines.
o Angle Constraint: Select two lines and apply an angle constraint.
4. Apply Geometric Constraints (if needed)

o Use Coincident, Tangent, Parallel, Perpendicular, etc., to control shape behavior.
5. Close the Sketch
o Once dimensioning is complete, click Close to exit the sketch.
6. Switch to TechDraw Workbench
o Change to the TechDraw workbench for annotation and documentation.
o Create a new drawing page using Insert Default Page.
7. Insert View of the Model
o Use Insert View to place the 2D projection of the model/sketch onto the drawing page.
8. Add Dimensions
o Use Add Horizontal/Vertical/Radius/Angle Dimension tools to place readable
dimensions on the view.
9. Add Text Annotations
o Click on the Add Annotation tool.
o Click on the drawing page to place the annotation.
o Enter the desired text (e.g., part name, notes, tolerances).
10. Adjust Formatting
 Modify font, size, and placement of dimensions and text via the property editor panel.
11. Save and Export
 Save your FreeCAD file.
 Export the TechDraw page as a PDF or SVG for documentation using File → Export PDF.
RESULT
Dimensional constraints were successfully applied to the sketch using the Sketcher workbench. Views
of the model were inserted onto a drawing sheet using the TechDraw workbench, and appropriate text
annotations were added.
CONCLUSION
In this experiment, important skills related to dimensioning and annotation were developed.
Dimensional constraints ensure parametric control, while the use of TechDraw allows creation of
professional-quality 2D documentation. This knowledge is essential for creating manufacturing-ready
technical drawings.

Experiment 5: Setting the Layers and Application of Layers
AIM
To learn how to organize elements in a 2D drawing using layers in FreeCAD and understand their
application in managing visibility, editing, and design clarity.
REQUIREMENTS
Hardware:
 A computer with minimum 4 GB RAM
 Full HD monitor (1920×1080 or higher)
Software:
 FreeCAD (version 0.20 or later)
 Required Python and OpenCascade libraries (bundled with FreeCAD)
THEORY
In many CAD applications, layers help in managing complex drawings by organizing similar elements
(e.g., dimensions, hidden lines, centrelines, etc.) into groups. FreeCAD does not have traditional layer
support like AutoCAD, but similar functionality can be achieved using the Draft Workbench and
groups or Draft VisGroups.
By assigning different objects or components into groups or setting display properties (like color, line
weight, and visibility), one can simulate the layer-based workflow. This method helps in controlling
visibility, making selective edits, and improving drawing clarity.
PROCEDURE
1. Launch FreeCAD
o Open FreeCAD and start a new project.
o Switch to the Draft Workbench.
2. Create Drawing Elements
o Draw some primitives such as lines, circles, or rectangles using the Draft tools.
3. Select Objects for Grouping
o Click to select the elements you wish to organize (use Shift or Ctrl for multiple
selection).
4. Create a Group (Simulating a Layer)
o Right-click in the Model Tree area.
o Select Create Group and name it (e.g., “Dimensions”, “Construction Lines”, etc.).

o Drag and drop your selected objects into the group.
5. Change Object Appearance by Group
o Right-click on the group name.
o Select Appearance and modify color, line thickness, transparency, etc.
o These properties apply to all objects within that group.
6. Control Visibility
o Use the eye icon in the model tree to toggle visibility of the entire group.
o This simulates the “On/Off” feature of traditional layers.
7. Using Draft VisGroups (Optional for Advanced Control)
o Install and activate the Draft VisGroup add-on if available.
o Use it to assign layer-like controls with more predefined layer properties.
8. Edit Objects in Groups
o Expand the group, double-click an element, and make required changes.
o Edits will not affect other groups unless objects are moved between them.
9. Create Additional Groups
o Repeat the above steps to create more groups and organize your drawing logically.
10. Save and Export
 Save the FreeCAD project.
 Export as .FCStd, .DXF, or .SVG for further use or printing.
RESULT
Drawing elements were successfully grouped into separate logical sets simulating layers. These groups
were customized in terms of appearance and visibility to manage a clean and organized drawing
environment.
CONCLUSION
Though FreeCAD does not natively support traditional layering like AutoCAD, similar functionality
was achieved using groups and appearance settings. This approach is essential for managing complex
designs, controlling element visibility, and ensuring design clarity and discipline in engineering
drawings.

Experiment 6: Isometric and Orthographic Projections
AIM
To understand the concepts of isometric and orthographic projections and to generate these projections
using FreeCAD tools.
REQUIREMENTS
Hardware:
 A personal computer with at least 4 GB RAM
 Graphics support for OpenGL 2.0 or higher
 Full HD monitor
Software:
 Compatible OS: Windows, macOS, or Linux
 Necessary libraries (included in FreeCAD)
THEORY
Isometric Projection represents a 3D object on a 2D plane with equal angles (120°) between each axis,
giving a pseudo-3D appearance.
Orthographic Projection, on the other hand, uses multiple 2D views (front, top, right, etc.) to represent
the object accurately from different directions.
In engineering drawings, orthographic views provide precise measurements, while isometric views
offer better visual understanding.
PROCEDURE
1. Launch FreeCAD
o Start FreeCAD and create a new project.
o Switch to the Part Design Workbench.
2. Create a 3D Object
o Design a simple object (like a box with a hole or a cylinder with chamfer).
o Use the Sketcher to draw the base profile and Pad or Revolve to create the 3D model.
3. Switch to TechDraw Workbench
o Go to Workbenches and select TechDraw.
o This workbench is used to create technical drawings including both isometric and
orthographic views.
4. Insert a New Drawing Page
o Click on Insert Default Page from the TechDraw toolbar.

o A drawing sheet will be added to the project.
5. Insert Orthographic Views
o Select the 3D model in the tree view.
o Click on Insert View → Insert Orthographic Projection Group.
o Choose views such as front, top, right, and isometric. The views will be generated
automatically on the sheet.
6. Adjust the View Settings
o Click each view on the drawing sheet.
o Use the property panel to change scale, projection method (First Angle or Third Angle),
and line thickness.
o Arrange the views neatly on the page.
7. Create a Standalone Isometric View (Optional)
o Select the object and choose Insert Isometric View separately if only an isometric
representation is needed.
8. Add Dimensions and Annotations
o Use the dimensioning tools in TechDraw to annotate the drawing.
o Add labels, centrelines, and section views if needed.
9. Save and Export
o Save the project in .FCStd format.
o Export the drawing sheet as PDF or SVG for printing or submission.
RESULT
Orthographic and isometric projections of a 3D model were successfully created using the TechDraw
Workbench in FreeCAD. The projections were dimensioned and organized for a technical drawing
sheet.
CONCLUSION
This experiment helped in understanding and visualizing the difference between isometric and
orthographic views. Using FreeCAD’s TechDraw Workbench, these views were created accurately for
engineering documentation. The experiment reinforced the importance of multi-view drawings in
design communication.

Experiment 7: Viewing in Three Dimensions
AIM
To understand how to view and manipulate 3D models from various angles using FreeCAD’s 3D
navigation tools and visual styles.
REQUIREMENTS
Hardware:
 A computer with a minimum of 4 GB RAM
 Graphics support for OpenGL 2.0 or higher
 Full HD monitor or better
Software:
 Operating system: Windows, macOS, or Linux
THEORY
In 3D modelling, it is essential to inspect objects from various perspectives to ensure proper shape, size,
and alignment. FreeCAD provides several viewing options such as top, front, side, isometric, and
custom views. Navigation tools like pan, zoom, and rotate allow for an interactive modeling experience.
The 3D View in FreeCAD is part of the main workspace where the model can be visually explored
using the mouse or view toolbar.
PROCEDURE
1. Launch FreeCAD
o Open FreeCAD and start a new project or open an existing 3D model.
2. Switch to an Appropriate Workbench
o Use Part Design, Part, or Draft Workbench as needed for your model.
3. Explore Standard Views
o Use the View Toolbar or the menu View > Standard views to select:
 Top View
 Front View
 Right View
 Left View
 Bottom View
 Rear View
 Isometric View
4. Use Mouse Navigation for 3D Viewing

o Rotate: Hold the middle mouse button and then left-click and drag.
o Pan: Hold the middle mouse button and then right-click and drag.
o Zoom: Scroll the mouse wheel forward/backward.
5. Use Navigation Cube
o Enable the Navigation Cube from Edit > Preferences > Display > 3D View.
o The cube helps switch views quickly by clicking on its faces, edges, and corners.
6. Change Display Modes
o Select the model and go to View > Draw Style or use the dropdown in the top bar.
o Explore different styles:
 Wireframe
 Shaded
 Flat lines
 Points
7. Toggle Axes and Grid
o Enable or disable the coordinate axes and grid through the view settings.
o This helps orient the model and understand its alignment in space.
8. Practice Rotating Around Specific Points
o Use the “Select then rotate” method to focus the rotation around a selected object or
feature.
9. Save the View Orientation (Optional)
o Use Tools > Save Picture or the Camera Icon to take a screenshot of the current 3D
view for reports or documentation.
RESULT
Various three-dimensional views of the model were explored successfully using FreeCAD. Different
visual styles and navigation techniques were used to examine the model from multiple perspectives.
CONCLUSION
This experiment provided hands-on experience in navigating and interacting with 3D models in
FreeCAD. Understanding these views helps in detailed inspection, error detection, and effective
presentation of CAD designs. These viewing skills are fundamental in design validation and review
processes.

Experiment 8: Removal of Hidden Lines – Shading and Rendering
AIM
To understand the visual representation of 3D models in FreeCAD by exploring shading, rendering
styles, and removal of hidden lines for better model visualization.
REQUIREMENTS
Hardware:
 Graphics card supporting OpenGL 2.0 or higher
 High-resolution monitor
Software:
 Operating system: Windows, macOS, or Linux
THEORY
In computer-aided design, hidden lines and surfaces often make the model appear cluttered or difficult
to interpret. Removing or hiding such elements can enhance visual clarity. FreeCAD offers several
display modes that allow viewing models in wireframe, shaded, or rendered form. These tools help in
evaluating the form and aesthetics of a 3D object, particularly before finalizing a design.
Shading and rendering refer to how light and shadows are simulated on the model surfaces, making
them appear more realistic and easier to analyze.
PROCEDURE
1. Open FreeCAD
o Launch the FreeCAD software and either create a new 3D object or open an existing
model.
2. Switch to a Relevant Workbench
o Use the Part, Part Design, or Mesh Design workbench for model manipulation.
3. Select the Model
o Click on the object to be viewed or modified.
4. Access Display Options
o Go to View > Draw Style from the top menu or use the visual style dropdown in the
toolbar.
5. Change to Different Visual Styles
o Experiment with the following styles:
 Wireframe – all edges visible, including hidden lines

 Flat Lines – smooth surfaces with edges shown
 Shaded – surfaces visible with basic shading
 Shaded with Edges – combines smooth surface and visible edges
 Points – only vertices are shown
6. Observe the Hidden Line Removal
o Switch from Wireframe to Shaded or Shaded with Edges.
o Note how hidden lines are automatically removed, and only the visible surfaces are
displayed.
7. Adjust Lighting and Appearance
o Right-click the object and select Appearance to:
 Change material color
 Modify transparency
 Enable or disable lighting effects
8. Render a Realistic View (Optional)
o For advanced rendering, install external FreeCAD workbenches like Raytracing or use
tools like LuxRender or Blender.
o Export the model as .STL or .OBJ if needed.
9. Take a Screenshot
o Use Tools > Save Picture to capture the visual output of the shaded or rendered view.
RESULT
The hidden lines of the 3D model were successfully removed, and the model was visualized using
different shading and rendering styles in FreeCAD for enhanced clarity.
CONCLUSION
This experiment demonstrated the importance of visual styles in CAD modeling. By removing hidden
lines and applying shading, models became easier to interpret and aesthetically pleasing. These
techniques are valuable for design presentations, technical documentation, and better geometric
understanding.

Computer Aided Design lab manual FreeCad.pdf

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