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Split and Trim

Reshape and divide geometries by splitting polygons and trimming away unwanted areas.

Written by Holly Conrad Smith

Split and Trim give you precise control over polygon boundaries. Use them when a site is subdivided, ownership changes, or your first geometry needs to be broken apart.

Split

Split cuts a polygon or line into pieces along a line you draw. Use it when a single site needs to become two lots.

  1. Select the polygon. OR skip this step and click the polygon after you start the tool.

  2. Press X, or click the Split tool in the drawing toolbar and choose Split.

  3. Click to place each point of a line through the polygon.

  4. Press Space or Enter, or click your last point again, to make the cut.

  • Hold Shift to constrain the angle of the line.

  • Type a number to set the length of a segment.

  • Hold S to snap to other geometries.

Each piece keeps the original geometry's properties. Split cuts every selected geometry the line crosses.

Offset split

Offset split cuts a polygon straight across at an exact distance along one of its edges. Use it to carve a lot to a set frontage, like a 20 m lot off the end of a block.

  1. Select the polygon. OR skip this step and click the polygon after you start the tool.

  2. Press Shift+X, or click the down arrow on the Split tool and choose Offset split.

  3. Move your mouse near the edge you want to measure along. A dashed cut line appears across the polygon, square to that edge. Two labels show the distance from each end of the edge to the cut.

  4. Type a number to set the distance exactly.

  5. Click, or press Enter, to make the cut.

  • Press Tab to lock the current cut and type the distance from the other end of the edge instead.

  • Press Esc to clear the cut and start over.

Offset split stays on after each cut, so you can keep cutting.

Each piece keeps the original geometry's properties. Offset split only works on single polygons. If a cut would leave a sliver too thin to keep, Giraffe leaves the shape whole.

Change how offset split works in the Tools menu under Offset Split. Splitting cuts through everything selected is on by default. Turn it off to cut only the polygon you're measuring along. Turn on Tab swaps the dimension to make Tab switch ends without locking the cut.

Trim

Trim cuts away part of a geometry along a line, like an area that falls outside a boundary.

  1. Draw a line that crosses the geometry.

  2. Select the line.

  3. Open the Command Bar and choose Trim.

  4. Click the part of each geometry you want to remove.

Trim uses one cutter line at a time.

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