This is a UI for making N-bar linkage systems with one degree of freedom and any number of rotary inputs. Here's an example making Theo Jasen's Strandbeest Linkage:

Play around with this example here: http://tinyurl.com/gwcuhhr

To run locally, first install npm, clone this repository, then run:

$ npm install
$ npm run-script build

Then open index.html with a browser (I've only tested in the lastest versions of Chrome). You should see a single, loney rotary input that looks like this:

Here are the controls so far:

• Press space to toggle pause
• When paused:
  • Click and drag a ground vertex to move it around
  • Some ground verticies are used as references for rotary inputs, so dragging them will change the phase the input
  • Hover over any bar*, then press w or s to change its length
  • To add an additional ground vertex connected to the linkage, click on two different places on the background, then click on a vertex on the linkage
  • To add additional bars, click a bar, or on any two verticies of the linkage, then click once on the background
  • To add a new rotary input, hold down r and then click somewhere on the background
  • To delete parts of the linkage, click on a vertex, then press d. Note that this only works if other parts of the linkage don't depend on the bars connected to the vertex.
  • To see the path that a vertex traces, click on a vertex, then press space to unpause
  • To automatically optimize the linkage to follow a path, click a vertex, then press o, then draw the desired path for that vertex. Press space to stop the optimization.
  • To select a rotary input, click the vertex that a bar is rotating around
• When unpaused:
  • Press w or s to increase or decrease the speed of a selected rotary input, or t to reverse its direction. If no rotary input is selected, these changes in speed will apply to all of them.

* any bar except one between a rotary input and its reference vertex

Rotary inputs will automatically reverse if they're about to put the linakge into an impossible configuration.