This python script, as the title implies, will allow you to loosely offset a curve. What this means is that the original point count of the curve will be kept in tact. Often when you are building curves that will later be used for (loose) lofts, they need to have a clean surface structure.
The only way to achieve this is by making sure that the point count and structure of each curve is the same.
There are different methods to make something like a loose offset, the simplest being scaling.While that might work well in some cases, it won't work well for example when the curve is mostly flat, or oddly shaped.This script will offset the control points of the curve, and build a new control-point curve through these points with the same degree as the original curve.
You can either copy and past the script below to Rhino for Windows' Python scripting editor, or if you're using Rhino for Mac, use the recommended Atom editor in combination with Rhino Python code completion support, which you can find here. To use the script on a Mac, load the script in Atom, and save the script as OffsetCrvLoose.py. Then in Rhino, run the command StartAtomEditorListener, so that Atom and Rhino can communicate with each other. To run the script, use ^⌥R.