Planar VS Spatial Close VS Open mm If every link in the chain is connected to two or more links then the chain form one or more closed loops. If NOT,the chain is said to be open. How to do kinematic analysis of a given mechanism? 99 Planar VS Spatial Close VS Open If every link in the chain is connected to two or more links then the chain form one or more closed loops. If NOT, the chain is said to be open. How to do kinematic analysis of a given mechanism?