Volumetric Cloud Materials

When using the Volumetrics Content plugin, dropping in the BP_CloudMaskGenerator and a BP_CloudMask_Object certain cloud materials such as M_VolumetricCloud_02_Profiles_PaintClouds_Morning link with the BP_CloudMask_Object and allow it to be moved, scaled and positioned around the scene. What is the property in the cloud volumetrics shader that allows it to link and move to the BP_CloudMask_Object? If we were to create our own cloud shaders, we want to be able to spawn BP_CloudMask_Object’s and move our custom cloud volumetrics around.

Thanks,