Combine, Merge, and Intersect Shapes in LibreOffice Draw

LibreOffice Draw provides built-in vector operations that allow you to construct complex custom graphics by combining, merging, subtracting, and intersecting basic 2D shapes. This guide explains how to access these shape operations, how each tool modifies your objects, and the practical steps needed to perform boolean transformations in your drawings.

Understanding the Shape Operations

LibreOffice Draw groups shape modification tools under the Shape menu. These tools perform boolean operations on two or more selected vector objects:

• Merge: Combines all selected overlapping shapes into a single polygon. The resulting shape adopts the outer boundary of all combined shapes, and interior overlapping lines are deleted. The merged shape takes the fill and line properties of the bottom-most object in the stacking order.
• Subtract: Uses the top shape(s) to cut into the bottom-most shape. The overlapping area and the top shapes are removed entirely, leaving behind only the modified bottom shape.
• Intersect: Creates a new shape consisting strictly of the overlapping region shared by all selected shapes. Any non-overlapping areas and original shapes are discarded.
• Combine: Connects multiple shapes into a single compound path. Unlike Merge, overlapping areas in combined shapes become transparent cutouts (holes). You can reverse this action later using the Split command.

How to Apply Shape Operations

Follow these steps to apply boolean operations to your vector shapes:

1. Insert Your Shapes: Draw two or more overlapping 2D shapes on the canvas using the toolbar (e.g., rectangles, ellipses, or custom polygons).
2. Set the Stacking Order: For Subtract and Merge, the layer order determines the outcome. If needed, right-click a shape, select Arrange, and adjust its position (e.g., Bring to Front or Send to Back).
3. Select the Objects: Hold the Shift key and click each shape you want to include, or click and drag a selection marquee around them.
4. Execute the Command:
   • Navigate to the top menu and select Shape.
   • Choose your desired operation: Merge, Subtract, or Intersect.
   • Alternatively, right-click the selection, hover over Shapes, and choose the command from the context menu.

How to Use Combine and Split

When you need overlapping areas to appear transparent rather than fused into a solid shape:

1. Select two or more overlapping vector objects.
2. Go to Shape > Combine (or press Ctrl + Shift + K).
3. To restore the individual shapes back into independent objects, select the combined object and choose Shape > Split.