You appear to be using the Piezo & MEMS ACT. It saves us time if you specify that your question pertains to a feature that is only available in the GUI when an extension such as the Piezo & MEMS ACT is installed.
Please look at the section starting on slide 146 in attached "ACT_Piezo & MEMS Extension_Lecture.pdf", which describes the usage of the capacitance extraction tool that the Piezo & MEMS ACT makes available. I also attached a relevant workshop (additional pdf and project archive) that will hopefully help you understand the usage of this feature.
These files are among those that are included in the Piezo & MEMS download. If you do not have access to these or have lost them, please try to download them once again from our Customer Portal. They describe all of the features that the Piezo & MEMS ACT make available in the Mechanical GUI.
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