To populate a custom metric so that it shows on the forecast grid, you can use either of the following options:
Implement a record trigger flow on Account Product Forecast (APF): A record trigger flow is a type of Salesforce Flow that runs when a record is created, updated, or deleted. You can use a record trigger flow to update the custom metric field on the APF object based on some logic or formula. The APF object stores the forecast data for each account and product combination. The custom metric field must be added to the APF object as a custom field. For example, you can create a record trigger flow that calculates the profit margin as a custom metric by dividing the revenue by the cost for each APF record1.
Implement a record trigger on Account Product Period Forecast (APPF): A record trigger is a type of Apex trigger that runs when a record is inserted, updated, deleted, or undeleted. You can use a record trigger to update the custom metric field on the APPF object based on some logic or formula. The APPF object stores the forecast data for each account, product, and period combination. The custom metric field must be added to the APPF object as a custom field. For example, you can create a record trigger that calculates the average revenue per unit as a custom metric by dividing the revenue by the quantity for each APPF record2.
The other options are not valid methods to populate a custom metric for the forecast grid.
Implementing an apex trigger on APF or APPF will not work because apex triggers cannot update the same object that triggered them. This will cause a recursive loop and throw an error3.
Using the recalculate all forecast button on the account forecast settings page will not work because this button only recalculates the existing metrics based on the account forecast calculation settings. It does not populate any custom metrics that are not part of the calculation settings4. References: 1: Create a Record-Triggered Flow | Salesforce Help 2: Triggers | Apex Developer Guide | Salesforce Developers 3: Apex Trigger Best Practices and the Trigger Framework - Salesforce Developers Blog 4: Recalculate All Forecasts | Salesforce Help