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Not a direct answer to the OP's question, but possibly helpful for those who are finding that Sketchup is no longer free.
As mentioned here by @ericmartinp: a perpetually free older version of Sketchup can be downloaded here.
Then, a version of the Euclid Sketchup plugin that works with that version can be found here.
I found this to be a working, free solution.
Not a direct answer to the OP's question, but possibly helpful for those who are finding that Sketchup is no longer free.
As mentioned here by @ericmartinp: a perpetually free older version of Sketchup can be downloaded here.
Then, a version of the Euclid Openstudio Sketchup plugin that works with that version can be found here.
I found this to be a working, free solution.