3D CAD is very well suited to designing mechanisms and can include flexible parts. This pumping concept was done in Inventor.
The device bellow is used to cap off two ducts under water and is gravity operated. It is lifted into place using hooks on the weight and then as the crane is lowered it swings against the ducts before the weight drops and closes the duct flange clamps
Another concept is shown below for plugging in a sub-sea cable. It first swings into position before removing and stowing a protective cap (pale blue) and then finally plugging in the connector. At each stage one operating hydraulic ram is taken through it's full stroke. This allowed for a very simple sequenced control of the whole cycle
The Benbow Group produce Specialist Joinery and Architectural Ironwork. They produce very high quality bespoke interiors which often include mechanisms for displays or doors etc. We have had the great pleasure of working with their highly skilled design department from time to time on some of these mechanisms, including a glass retracting wine cellar door.