As of Grapher 15, you can define custom fits to graphs in Grapher by adding a fit curve to one class, or to all classes in a class scatter plot. To do so:

1. In the Object Manager, select the class scatter plot you wish to add the fit curve to.
2. Click Home | Add to Graph | Fit Curve.
3. In the Object Manager, select the fit curve plot.
4. In the Property Manager, click the Plot tab.
5. In the Fitted Plot section, in the Class field, either choose a specific class to fit the curve to, or select (All).

To edit any aspect of the fit curve, you can select the fit curve in the Object Manager and then edit the various parameters (such as the Fit type and Plot Interval) In the Property Manager. More details on editing fit curves can be found here: Grapher Fit Curves Training Video

Updated March 2023