Grasshopper c# - set object attributes

[Jane.Cho]

Hi!

I was wondering how to set object attributes (properties) in rhino grasshopper c# script.
Elefront plugin would do the job, unfortunately it does not support Mac OS.

I wish to set key and value string on curves to use object information for rhino inside Revit.

here… where you can check properties/attributes in rhino

I tried this method ObjectAttributes.SetUserString
https://developer.rhino3d.com/api/RhinoCommon/html/M_Rhino_DocObjects_ObjectAttributes_SetUserString.htm

and wrote short script below :

ObjectAttributes attri = new ObjectAttributes();
attri.SetUserString(key, value);

foreach(GH_Path path in crvs.Paths){
foreach(Curve cry ln in crvs.Branch(path)){
crv.Attributes = attri;
}
}

and it returns an error message says

1. Error (CS1656): Cannot assign to ‘Attributes’ because it is a ‘method group’ (line 74)

Could you give some advice how to make this script work?
Thanks!

[Baris]

something like this may help:

private void RunScript(GeometryBase geo, object y, ref object A)
  {
    var oa = new Rhino.DocObjects.ObjectAttributes();
    oa.SetUserString("test", "value");
    Rhino.DocObjects.Tables.ObjectTable ot = Rhino.RhinoDoc.ActiveDoc.Objects;
    ot.Add(geo, oa);
  }

[Jane.Cho]

Thanks! your suggestion worked as I expected.
Could you help me one more question?

Here is the screenshot of my script

when I bake the result, it creates duplicated line (one with attributes, the other without attributes) and I assume it is because I created new Rhino.DocObjects.Tables.ObjectTable class.

Is there any way to cull duplicated line (the line without attributes)?

Here attached .gh script just in case.
duplicatedResult.gh (18.1 KB)

Thanks for your help!

[Joseph_Oster]

What is very strange is that you have 420 lines going into your C# script and 420 lines coming out. Yet baking the output Line gives you 840 lines while baking the input Line gives only 420, as expected.

P.S. Oh, I see what’s happening by toggling the ‘run’ input. The lines are already “baked” by just running the script so there is no need to bake the output?

@Jane.Cho

Here attached .gh script just in case.

“Just in case”? It’s always valuable to post code!

[Baris]

Not sure why you are looping in that (strange?) manner through the tree, but this way seems to work.

 if(run)
    {
      ObjectAttributes attr = new ObjectAttributes();
      attr.SetUserString(key, value);
      for (int i = 0; i < baselines.BranchCount; i++)
      {
        for (int j = 0; j < baselines.Branch(i).Count; j++)
        {
          Rhino.DocObjects.Tables.ObjectTable ot = Rhino.RhinoDoc.ActiveDoc.Objects;
          ot.AddLine(baselines.Branch(i)[j], attr);
        }
      }
      A = baselines;
    }

[Joseph_Oster]

@Baris

this way seems to work

It works the same way as what @Jane.Cho already had. The ‘AddLine()’ method “Adds a line object to Rhino”, effectively “baking it”, so baking the output is what causes the duplication.

https://developer.rhino3d.com/api/RhinoCommon/html/Methods_T_Rhino_DocObjects_Tables_ObjectTable.htm

[Baris]

Not sure, can you attach these properties without baking?
how would you do it in elefront?

[Jane.Cho]

In elefront component, if user update/change attribute value (key or value string) and click ‘bake’ button it automatically update attributes without baking new object.
However in my script, if I change the attribute value, the component bake new object with updated input value. Thus I get two objects with different attributes in Rhino.
Anyway thanks a lot for the comments!

[Baris]

So it just works for rhino objects as I understand for now, not for gh geometry.

[Joseph_Oster]

@Jane.Cho

However in my script, if I change the attribute value, the component bake new object with updated input value. Thus I get two objects with different attributes in Rhino.

To be a little more precise about this, your C# code “bakes” your lines with assigned attribute (key, value) due to ‘ot.AddLine()’ but the attribute is not added to the ‘A’ output.

And adding a ‘nl’ array doesn’t help (I just checked):

private void RunScript(bool run, DataTree<Line> baselines, string key, string value, ref object A)
{
    if(run){
      ObjectAttributes attr = new ObjectAttributes();
      attr.SetUserString(key, value);
      Line[] nl = new Line[baselines.DataCount];
      int i = 0;
      foreach(GH_Path path in baselines.Paths){
        foreach(Line ln in baselines.Branch(path)){
          Rhino.DocObjects.Tables.ObjectTable ot = Rhino.RhinoDoc.ActiveDoc.Objects;
          ot.AddLine(ln, attr);
          nl[i] = ln;
          i = i + 1;
        }
      }
      A = nl;
    }
}

duplicatedResult_2021_Aug9a.gh (22.7 KB)

Neither does this:

private void RunScript(bool run, DataTree<Line> baselines, string key, string value, ref object A)
{
    if(run){
      ObjectAttributes attr = new ObjectAttributes();
      attr.SetUserString(key, value);
      List<Line> nl = new List<Line>();
      foreach(GH_Path path in baselines.Paths){
        foreach(Line ln in baselines.Branch(path)){
          Rhino.DocObjects.Tables.ObjectTable ot = Rhino.RhinoDoc.ActiveDoc.Objects;
          ot.AddLine(ln, attr);
          nl.Add(ln);
        }
      }
      A = nl;
    }
}

duplicatedResult_2021_Aug9b.gh (22.4 KB)

[Jane.Cho]

Thanks for the comment! You are correct, by using AddLine method it automatically bake lines in Rhino.

Here I figured out the script that works for my situation. It is no professional code, but hopefully this will help someone who has similar question

if(bake){
    ObjectAttributes attr = new ObjectAttributes();
    Rhino.DocObjects.Tables.ObjectTable ot = Rhino.RhinoDoc.ActiveDoc.Objects;
    attr.Name = bakeName;

    //delete previous table by filtering 'bakeName'
    Rhino.DocObjects.ObjectEnumeratorSettings settings = new Rhino.DocObjects.ObjectEnumeratorSettings();
    settings.NameFilter = bakeName;
    System.Collections.Generic.List<Guid> ids = new System.Collections.Generic.List<Guid>();
    foreach (Rhino.DocObjects.RhinoObject rhObj in doc.Objects.GetObjectList(settings)){
        ids.Add(rhObj.Id);
    }

    if (ids.Count == 0){
        Print("No objects with the name " + bakeName);
    }else{
        //delete previous object table by ID in Rhino
        foreach (Guid id in ids) {
            ot.Delete(id, true);
        }
    }

//add new attributes in object table
    foreach(GH_Path path in baselines.Paths){
        int level = path.Indices[0];
        for(int i = 0; i < baselines.Branch(path).Count; i++){
            //bakeName
            attr.SetUserString(attri[0], bakeName);
            string floorLevel = "Level_" + level.ToString();
            attr.SetUserString("FloorLevel", floorLevel);
            ot.AddCurve(baselines.Branch(path)[i], attr);
        }
    }
}