With this cluster you will be able to avoid the problem coming from the gh conversion from geometry to mesh cluster.
If you input any closed curve in the stndard mesh cluster it will convert them to planar meshes.
This cluster help you avoid it by giving back only the mesh filtered objects among the input ones.
To add this user object, go to Files > Special Folder > User Object Folder & paste the .ghuser file into the folder. You can find the component under CalNic in the Grasshopper Plugins Tabs.
For info and suggestions: firstname.lastname@example.org