If a mesh is good enough, the Rhino command "MeshToNURB" may be used to convert the mesh into a valid boundary representation of a solid. The mesh polygons become legitimate faces of the solid, and Scan&Solve may be used to perform stress analysis as with any other valid boundary representation. However, for this to work, the mesh must satisfy several fairly technical conditions, including:
These conditions may be verified and corrected using the Mesh Repair and Mesh Edit tools in Rhino. In addition, currently Rhino restricts the MeshToNURB command to meshes with fewer than 20,000 faces.
A brief video demonstrating Scan&Solve analysis from meshes may be viewed here.