Hello @cpalmers,
You have two options to compute volumes in PIX4Dsurvey after creating your volume measurements.
The first one is the one mentioned by @mark.nunn: select the volume you want to compute, and click on the Compute button in the Properties panel that is on the right by default. Note that in versions prior to 1.59.0 this button was in the lower part of the Content panel, on the left.
The second option is to use the Compute outdated volumes action in the Layers 3-dot menu, available since version 1.57.0. Note this will compute the volume for all outdated volumes, not only the one selected, contrary to the first method.
Using any of these methods, your volumes will be computed and you will see the results in the Properties panel, these volumes will then be available for the volume report.
For more information on the volume measurement in PIX4Dsurvey, please visit Volume measurement - PIX4Dsurvey
Best regards,
Jessica