vasturiano / d3-force-registry Goto Github PK

Thanks so much for curating and assembling this. As I mentioned on Twitter, I think beeswarm not M.Bostock and force in a box belong here. If so, I will happily submit pull.

Great resource! Is it possible to add d3-force-reuse to your registry? Here is an example row you could add to the table:

Would you also consider this as a good spot to collect other resources, such as videos and presentations? If so, will gladly help collect links.

Wasn't too sure where to post this, but this repo seems to curate d3-force plugins for use in (perhaps) unusual use-cases, like physical simulations - so figured I'd alert users to energy-conservation in d3-force.

In particular, the Pendulum example asks:

Ok, I'm confused. Why isn't energy conserved and does the pendulum eventually stop?

Similarly, the Newton's Cradle example also 'thermalizes' albeit both explicitly setting:

d3.forceSimulation()
	.alphaDecay(0)
	.velocityDecay(0)

The issue is that d3.forceLink actually performs iterative relaxation. The offending lines in the source code are:

        x = target.x + target.vx - source.x - source.vx || jiggle(random);
        y = target.y + target.vy - source.y - source.vy || jiggle(random);

Note the link distance is specified by 'peeking ahead' to the anticipated position of the node ⟨x + vx,y + vy⟩.

This notebook further explains the issue using examples, and suggests two alternatives.