A simple plugin providing the source for node(s) solving V-Chain IK hierarchies with soft-solution options
This is being worked on for the January 2019 Patreon reward of Cult of Rig.
Please note that this is offered mostly for its pedagogic value. It's not a bad option since it's not exactly raining closed-form solvers out there, even for simple cases like a vChain, but the code itself is written and laid out to teach about the solver, not necessarily to be the fastest or most optimal.
If you want to try and shave a few micro-seconds from it, please, feel free. Just know that the solution part of the node cost is already less than 20% of the evaluation cost, most of it is handle taxes and Maya's internal coordination.
Source is available to under BSD 3 Clause, and the binaries for Maya 2018 are provided in the dist directory. Most people should be able to use the AVX2 binary, but if you have an old CPU (pre-Haswell for intel or pre-Ryzen for AMD) you might have to use the SSE 4.2 (SSE2) version to avoid crashes.
A demo scene is available in the demo directory with two set-up's showing hierarchical and flat modes.