1.25 Concave Hull


The Concave Hull app is used to creates a bounding area enveloping a set of 2D points.


  1. We will use the sample project file in this tutorial. Right click the Concave Hull app icon Concave Hull icon.png in the App Gallery and select Show Samples in Folder. In the folder that opens, drag -and-drop example.opju file into Origin workspace to open it.
  2. The contour in Graph1 is created from columns A-C in [Book1]Sheet1. We can see that there should be a hole in the contour, which is now filled with color as well. We will use Concave Hull app to create boundaries. With the contour active, click Concave Hull app icon Concave Hull icon.png from App Gallery. The Concave Hull dialog will open.
  3. By default, if the active plot is created from XY datasets, it will be auto-picked as input. However, in this example, contour is created from XYZ datasets. So we will need to add it as Input manually.
  4. Enter 0.1 for Alpha. Note that you can check Auto Preview checkbox at the bottom to see the boundaries changes according to the alpha value.
    Concave Hull Settings.png

    Click OK button.
  5. A red boundary line are added to the graph. And its XY coordinates appends to the source worksheet, [Book1]Sheet1.
  6. To use this boundary for contour, double click on the contour to open the Plot Details dialog. Active Contouring Info tab on the right panel. Check Custom Boundary check box and select the newly added column D and E for Boundary X Data and Boundary Y Data respectively.
    Concave Hull Plot Details Settings.png

    The final graph should look like following:
    Concave Hull Contour.png