I'm trying to subtract two surfaces, which are shown below in this image, by using VTK or ParaView. I'm aware of vtkBooleanOperationPolyDataFilter but that filter needs its inputs to be closed manifolds, which is not the case for me. In fact, I want to subtract that orange surface from that cylinder. I'm pretty sure those surfaces are in close contact that it should be possible to subtract them properly but I searched a lot about it but I didn't find a proper way. I appreciate any help or suggestion.