In the attached video you can see how the link between Spark3D and CST Studio Suite works by using as an example, a dielectric-loaded cavity filter. The video presents a Spark3D new development that enables the multipactor analysis when more than one surface material is present within the device.
It shows how to export the EM fields computed in CST Studio Suite and import them into Spark3D. Once imported, the surface materials can be visualized and a multipactor simulation configured. Finally, a simulation is done to show how Spark3D runs and how results are presented.