How to Animate Mechanical Movements in FreeCAD

This guide provides a step-by-step walkthrough for creating keyframe animations of mechanical movements in FreeCAD. You will learn how to install the appropriate animation tools, prepare your mechanical parts, define keyframes along a timeline, adjust movement interpolation, and render the final animated sequence.

1. Install the Animation Workbench

FreeCAD does not include a dedicated keyframe timeline editor in its default installation. The most efficient way to achieve timeline-based keyframe animations is by installing the Animation Workbench.

  1. Open FreeCAD.
  2. Go to Tools in the top menu and select Addon Manager.
  3. In the Workbenches tab, locate Animation.
  4. Click Install.
  5. Restart FreeCAD when prompted to finalize the installation.

2. Prepare the Mechanical Components

Proper part hierarchy and origin placement are critical for realistic mechanical motion, such as pivots, rotations, and sliding actions.

  1. Ensure each moving part or sub-assembly is grouped logically or modeled as distinct solid bodies.
  2. Adjust the placement origins of rotating parts. A hinge, gear, or lever must have its local coordinate system centered on its pivot point so that rotating along an axis (X, Y, or Z) produces the correct mechanical movement.
  3. Switch to the Animation workbench from the workbench dropdown list.

3. Create a Timeline Manager

The Animation Workbench relies on a central manager to control the timing, frame rates, and execution of movements.

  1. Click the Create a Manager icon in the Animation toolbar.
  2. In the Tree view, select the newly created Manager object.
  3. In the Property panel under the Data tab, configure the project settings:
    • Start Time: Typically 0.0.
    • End Time: Set the total duration of the animation in seconds or frames.
    • Time Step: Set the interval between frames (e.g., 0.04 for roughly 25 frames per second).

4. Add Animators and Keyframes

Animators link specific properties of your mechanical parts (such as rotation angles or linear offsets) to the timeline.

  1. Select the component you want to animate from the Tree view.
  2. Click Create an Animator in the toolbar.
  3. In the Property panel of the Animator:
    • Set Property to Animate: Select the specific property (for instance, Placement.Rotation.Angle for rotating shafts or Placement.Base.x for sliding pistons).
  4. Add your initial keyframe:
    • Set the component's position at the start time.
    • Add the initial value to the Animator's keyframe list.
  5. Move the timeline forward to the desired time marker.
  6. Adjust the target mechanical property to its new position and commit the second keyframe.
  7. Repeat this process for each moving part in your mechanical assembly.

5. Adjust Interpolation and Constraints

To make the mechanical action appear physically accurate:

  1. Select the Animator for each part.
  2. Choose the interpolation mode between keyframes:
    • Linear: Best for constant-speed motors, conveyor belts, and standard mechanical feeds.
    • Ease-In / Ease-Out: Ideal for mechanisms starting from a rest position or coming to a stop due to inertia.

6. Preview and Export the Animation

  1. Select the Manager object in the Tree view.
  2. Use the Play, Pause, or frame-scrubbing controls in the Animation toolbar to review the mechanical motion directly inside the 3D viewport.
  3. To export the sequence, open the export dialog within the Animation workbench to render individual image frames (such as PNGs) of each time step.
  4. Compile the generated image sequence into a video format (such as MP4) using external tools like FFmpeg, Blender, or any dedicated video editing software.