Toolbar / Icon:
Add-on:  QCAD Professional
Menu: Draw > Polyline > Morph
Shortcut: O, M
Commands: polylinemorph | om


With this tool, you can morph between two polylines. A number of new intermediate polylines are created. Each intermediate polyline is a mix of the two chosen polylines. With each step of the morphing operation, the position and shape of the first polyline is transformed to be more like the second polyline.


  1. Prepare the two polylines.
    Usually the two polylines should have the same direction or orientation. For closed polylines, you would typically want the start point to be aligned, so that no rotation occurs while morphing. More complex polylines can be split at sharp corners to maintain the position of those corners throughout the morphing process.
  2. Launch this tool.
  3. Enter the number of desired steps in the options toolbar.
  4. Choose the desired easing function in the options toolbar. The normal easing function is "linear" which interpolates linearly between the two polylines. Easing functions can be used to create various uneven types of interpolations.
    For example to start morphing at the first polyline, first advancing slowly toward the second polyline and then accelerate toward the second polyline in a quadratic function, choose "in quadratic".
  5. Click the first polyline. You can also select a line, an arc, a circle, an ellipse or a spline.
  6. Click the second polyline.
  7. The entered number of intermediate polylines is created.

In this example, the rounded rectangle is morphed to the ellipse in nine steps. Both shapes are first converted into polylines (the ellipse is exploded into a polyline with arc segments). The startpoint of the rounded rectangle is set to be at the bottom center (1). The start point of the ellipse is set at its bottom center (2). Both polylines are made counter-clockwise.