Digitizing Material Curves (with SpyCurve)

Our Project Engineers were tired to manually extract material data and properties from PDF documents and images. So we developed SpyCurve as a Free add-on to Grapheme and Nexus

How It Works

The SpyCurve add-on works by loading an image (among the supported formats: *.bmp, *.png, *.jpg, *.tif) and allowing you to transform screen coordinates in real-world coordinates so that every time you click on the screen the point is transformed in the image axes and saved in a tabular format.

The process follows four simple steps:

1. Import the image


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Once the SpyCurve wizard opens up, you can select the image you wish to digitalise. Supported formats are: *.bmp, *.png, *.jpg, *.tif.
Once the image loads up, this is displayed in the lower part of the wizard.
Press Next to move to the calibration page.

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2. Calibrate SpyCurve

The calibration process requires to select two points from the image providing their corresponding real-world coordinates.


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In this specific case, we select as first calibration point the bottom left corner and we assign it coordinates (0.0, 0.0) and as second calibration point the top right corner having coordinates (20.0, 300.0).

Once the calibration process is completed, press Next to move to the point-selection page.

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3. Pick Points

Once the calibration process is completed, real-world coordinates are displayed on the chart when hovering the mouse.


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Points can be picked-up by clicking with mouse:

  • Left click to add a new point to the current series
  • Right click to remove the closest point from the current series

Please note that you can extract multiple series at the same time by using the series selector on the left of the Wizard toolbar.
The toolbar also allows you zoom in/out and to pan the image to allow you achieving higher precision when extracting sample points.

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4. Review and save data

On this final step, the tool display all the points selected so far, organized in tabular form. If more series have been extracted, the tool offers different options to merge data to assure for examples they are all expressed with respect of the same X coordinates.
Resulting table can thus be saved on file or directly within the current project if any opened.

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Installing the Add-on


The SpyCurve add-on is not installed by default. However it can be easily installed from the main menu either of Grapheme or Nexus.
Simply click on: Help => Install New Software and select SpyCurve from the list of available plugins.

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