GrasshopperAsyncComponent

Less Janky Grasshopper Components

See the companion blog post about the rationale behind this approach. This repo demonstrates how to create an eager and responsive async component that does not block the Grasshopper UI thread while doing heavy work in the background, reports on progress and - theoretically - makes your life easier.

We're not so sure about the last part! We've put this repo out in the hope that others will find something useful inside - even just inspiration for the approach.

Looks nice, doesn't it? Notice that the solution runs "eagerly" - every time the input changes, the the computation restarts and cancels any previous tasks that are still running. Once everything is done calculating, the results are set. And the best parts:

• Grasshopper and Rhino are still responsive!
• There's progress reporting! (personally I hate waiting for Gh to unfreeze...).

Approach

Provides an abstract GH_AsyncComponent which you can inherit from to scaffold your own async component. There's more info in the blogpost on how to go about it.

Even better, there's a sample component that shows how an implementation could look like! There's two components in that folder:

• The Useless Spinner: does no meaningfull CPU work, just keeps a thread busy with SpinWait()
• The N-th Prime Calculator: can actually spin your computer's fans quite a bit (for numbers > 100.000)

Current limitations

Main current limitation is around data matching. Solved! See this PR. Components inheriting from the GH_AsyncComponent class can now nicely handle multiple runs and any kind of data matching:

Flash of null data Solved! These Async Components now only expire their downstream dependants when they're done with their tasks.

Other limitations:

• This approach is most efficient if you can batch together as many iterations as possible. Ideally you'd work with trees straight away.

• Task cancellation is up to the developer: this approach won't be too well suited for components calling code from other libraries that you don't, or can't, manage.

FAQ

Q: Does this component use all my cores? A: OH YES. It goes WROOOM.

Q: Can I cancel a stuff that's in progress?

A: Yes. The GH_AsyncComponent class now exposes the RequestCancellation() method, which you can invoke from a custom menu action, or however you want. Note, to properly handle this and ensure the component's inner flow state is properly reset, when respecting the cancellation in your component, you should call the Done() function before returning from DoWork(). E.g.:

public override void DoWork(Action<string, double> ReportProgress, Action Done)
{
  // note: call done from inside DoWork(), then return abruptly. 
  if (CancellationToken.IsCancellationRequested) { Done(); return; } 
  // more code
}

Debugging

Quite easy:

• Clone this repository and open up the solution in Visual Studio.
• Once you've built it, add the bin folder to the Grasshopper Developer Settings (type GrasshopperDeveloperSettings in the Rhino command line) and open up Grasshopper.
• You should see a new component popping up under "Samples > Async" in the ribbon.
• A simple

Contributing

Before embarking on submitting a patch, please make sure you read:

• Contribution Guidelines,
• Code of Conduct

License

Unless otherwise described, the code in this repository is licensed under the Apache-2.0 license.