MATLAB: Low-level plotting functions

MATLABplotting

does Matlab have any low-level plotting functions, such as plot a point or a line, or a polyline? I cannot find any in the documentation

Yes.

Why not ask this question over at CoolProp (issues or mailing list)? Much better chance of a response. That said, there are now examples online in the development docs: http://www.coolprop.org/dev/coolprop/wrappers/MATLAB/index.html#example-code

No, there is not.

In the special case that you are changing all of the fields, you can do something like

level1.level2(3).time = struct('best',  something, 'worst', somethingElse, 'Avg', somethingAvg);