Use the Volume Extract tool in the Analysis group on the Prepare tab to create a solid based on the volume enclosed by a single body or set of bodies (including meshes). A solid named Volume is created in the Structure tree, and the bodies used to generate the volume are temporarily transparent when the volume is created.
If a surface intersects all of the edges you select to enclose the region, it will be used to cap the created volume. You can create cleaner caps by placing surfaces at each of the edges you use to define the enclosed region.
Download files: Pipe & Impeller