How to Import Blueprint Images in FreeCAD

Importing a blueprint or reference image into the FreeCAD 3D viewport allows you to trace contours and match real-world dimensions directly within your design environment. By using the dedicated Image Workbench, you can place 2D raster files onto specific planes, scale them to real-world dimensions, and adjust their opacity so they serve as reliable guides while you model in workbenches like Part Design or Sketcher.

Step 1: Switch to the Image Workbench

Launch FreeCAD and open your existing project or create a new document. In the top toolbar, click the workbench drop-down menu (which defaults to "Start" or "Part Design") and select the Image workbench.

Step 2: Load the Blueprint into the 3D Viewport

  1. Click the Create a planar image in the 3D space button on the toolbar (represented by an icon showing an image on an axis plane).
  2. Browse your file system to select your blueprint image (supported formats include PNG, JPG, BMP, and SVG).
  3. In the dialog box that appears, select the plane that matches your blueprint's view:
    • XY-Plane for top/bottom views.
    • XZ-Plane for front/back views.
    • YZ-Plane for side/profile views.
  4. Click OK. The image will now appear in your 3D viewport centered at the origin.

Step 3: Calibrate the Image Scale

Blueprint images are not imported at actual scale by default. To scale the drawing to match real-world measurements:

  1. Locate the imported image object in the Tree View (labeled as ImagePlane).
  2. Click the Scale an image plane tool on the Image toolbar.
  3. Click the first point on a known dimension line in your blueprint.
  4. Click the second point on that same dimension line.
  5. In the pop-up window, enter the actual target distance (for example, 150 mm) and confirm. The entire image will resize proportionally to real-world scale.

Step 4: Adjust Transparency and Positioning

To model effectively over the blueprint without obscuring your sketch lines:

  1. Select the ImagePlane in the Tree View.
  2. In the Property View panel at the bottom left, switch to the View tab.
  3. Adjust the Transparency setting to roughly 50% to 70%.
  4. Switch to the Data tab to adjust the Placement values. Here, you can translate the image along the X, Y, or Z axis to align key reference features (such as centerlines or corners) directly with the FreeCAD global origin, or push the image slightly behind the sketch plane to prevent graphical clipping.

Once positioned and scaled, switch to the Part Design or Sketcher workbench to create sketches directly over the calibrated reference image.