Getting Component "input" sources.

Replies to This Discussion

Permalink Reply by Dimitrie Stefanescu @idid on October 2, 2015 at 11:16am

Ok, I'm going to have a dialogue with myself for a bit. I'm slowly getting there: 

GH_Document g = new GH_Document();

A = g.FindAllDownstreamObjects(Component);

Works fine for all the downstream (ie to the right) components. Unfortunately there's no... "FindAllUpstreamObjects(this)" :( 

Permalink Reply by David Rutten on October 3, 2015 at 7:11am

Assuming you have a component called comp and you want to find all top level objects that are immediate sources, here's what you can do (top of my head code):

HashSet<Guid> ids = new HashSet<Guid>();

foreach (IGH_Param param in comp.Params.Inputs)

  foreach (IGH_Param source in param.Sources)

  {

    Guid id = source.Attributes.GetTopLevel.DocObject.InstanceGuid;

    ids.Add(id);

  }

List<IGH_DocumentObject> objects = new List<IGH_DocumentObject>();

foreach (Guid id in ids)

{

  IGH_DocumentObject obj = doc.FindObject(id, true);

  if (obj != null)

    objects.Add(obj);

}

You need to always use GetTopLevel() because a parameter source may be an output parameter of a component, and that is a subobject. If you want the component itself you'll need to use Attributes.GetTopLevel.DocObject

The reason to use a HashSet is because a specific object may be a source for the current object more than once. The HashSet prevents double entries.

Permalink Reply by Dimitrie Stefanescu @idid on October 5, 2015 at 12:36pm

All smooth. Works! Minor typos needed a fix. 

Now i'm in another fix though. How do I get the input sources of the IGH_DocumentObject? Hopefully once I get my head around the GH principles I'll stop asking annoying questions!

Before I get bashed, I am reading and searching through the Grasshopper SDK :) 

Permalink Reply by Dimitrie Stefanescu @idid on October 5, 2015 at 1:07pm

Answering my own question: 

Simple, just cast to IGH_Component instead of IGH_DocumentObject. 

I am though wondering what the difference is between IGH_Component and IGH_DocumentObject. I'm sure I'm missing some rather important logic here! Asking in the hope of putting less annoying questions in the future, obviously. 

Permalink Reply by David Rutten on October 5, 2015 at 6:56pm

IGH_DocumentObject is anything that exists on the canvas. Components, sliders, scribbles, groups, jumps, panels, everything except the widgets like Compass and Profiler. IGH_ActiveObject are those objects on the canvas that participate in solutions. This includes all components and parameter, but does not include groups, scribbles, sketches, etc. IGH_Param is for parameters, be they freefloating or attached to components, IGH_Component is for components. What IGH_Component adds to IGH_ActiveObject is little more than a unified way to access the input and output parameters. The abstract GH_Component class (which implements IGH_Component) does a lot of stuff, but usually you're better off casting to IGH_Component than GH_Component.

Permalink Reply by Dimitrie Stefanescu @idid on October 6, 2015 at 2:32am

Thanks for the explanation - it clarifies a lot! 

I did stumble ina problem last eve, IGH_Component could not be cast to a number slider - when I was reaching that point I figured I started looking again, and probably end up using IGH_ActiveObject. 

All cool, progress is being made (painfully slow).  

Permalink Reply by David Rutten on October 6, 2015 at 3:07am

Correct, a number slider is a GH_Param<GH_Number> or IGH_Param. Most of those special objects are IGH_Params with the notable exception of Gradients and Legends. Parameters are much easier to modify and tweak, but they can only have a single input and a single output, which is some rare cases is insufficient.

Permalink Reply by Anton Szilasi on March 31, 2017 at 9:48am

Just incase someone is ever looking for something like this I wrote a recursive function which will find all the upstream components (and params) that are connected to a particular component.

It was written for the ghPython components, but the code could be converted to C#

Attachments:

• FindUpstreamComponents.py, 2 KB

Permalink Reply by Arend on October 2, 2015 at 10:58pm

Hey dimitrie, how are you?

Do you mean this?

    var document = this.GrasshopperDocument;
    A = document.FindAllDownstreamObjects(this.Component);

Permalink Reply by Dimitrie Stefanescu @idid on October 5, 2015 at 1:08pm

Mmm, kind-of, though what I'm trying to do now is akin to document.FindAllUpstreamObject(etc)!

Will share some final code once I've glued my hack to something usable.