When does CameraPipelineModule onUpdate trigger?

I am using the Legacy Editor.

I am attempting to re-render the scene after users change a dat gui slider, as this reforms some of the meshes. However, calling renderer.render(scene, camera) in the method within the scene pipeline module (called on start) does not work. It seems re-rendering on update would be the best move, but the documentation is not clear on when/how update event is triggered.