Note that if point N has M in its ConnectionsIndices array, and point M has N in its ConnectionsID array, there are effectively two springs and/or dampers in parallel between N and M. You may need to adjust accordingly (for example, use half the value) to get the desired result if you only wanted one spring or damper.
If a point has itself in its own ConnnectionIndices array, that connection is ignored. The corresponding entries in the ConnectionMute, DamperCoeffs, SpringCoeffs, and SpringLengths arrays are also ignored.
If you want to combine spring-only connections and damper-only connections on the same object, set the appropriate coefficients to 0.0. For example, if you want the Nth element in the ConnectionIndices array to be a spring only, set the Nth element in the DamperCoeffs array to 0.0. Conversely if you want the Mth element in ConnectionIndices to be a damper only, set the Mth element in SpringCoeffs to 0.0.