Output Lists to Tree Branches

Hello,

I am attempting to take a list(s) and append it to a datatree using AppendRange. The trouble I am having is the lists are not being added as individual branches. When I check the tree with PathCount the correct quantity of paths is returned. How is that possible?

I have also tried to add the individual elements (that would otherwise make up each list) one at a time to the same path. Basically using Append in the nested foreach loop rather than adding the elements to a list. This also did not work.

I've searched the forum for answers and can only seem to come up with bits and pieces of information that so far haven't helped find a solution. I suspect the solution is something obvious.

Code in question:

protected override void SolveInstance(IGH_DataAccess DA)
{
List<Brep> nodeList = new List<Brep>();
if (!DA.GetDataList(0, nodeList)) return;

List<GH_Line> lineList = new List<GH_Line>();
if (!DA.GetDataList(1, lineList)) return;

GH_Structure<IGH_GeometricGoo> tree = new GH_Structure<IGH_GeometricGoo>();

for (int i = 0; i < nodeList.Count; i++)
{
var bbox = nodeList[i].GetBoundingBox(true);

GH_Path path = new GH_Path(i);
List<GH_Line> branch = new List<GH_Line>();

foreach (GH_Line line in lineList)
{
if (line.Value.From.EpsilonEquals(bbox.Center, 0.001) || line.Value.To.EpsilonEquals(bbox.Center, 0.001))
{
branch.Add(line);
}
}
tree.AppendRange(branch, path);
}

Rhino.RhinoApp.WriteLine(tree.PathCount.ToString());
DA.SetDataList(0, tree);

}

Thanks!

Replies to This Discussion

Permalink Reply by jc on September 5, 2017 at 9:36am

No ideas on this one? Are the missing examples in the SDK, https://goo.gl/UuAutg, for writing trees available anywhere?

Permalink Reply by David Stasiuk on September 5, 2017 at 11:34am

Is there a particular reason you're using AppendRange rather than appending them one by one?

Permalink Reply by jc on September 5, 2017 at 1:12pm

Thanks for the reply! Append did not work either. Using Append to add elements one by one or AppendRange to add them as lists result in a tree where PathCount returns the correct number of paths but the ultimate tree structure output in Grasshopper is a single path (single branch?) containing all of the elements.

Permalink Reply by David Stasiuk on September 8, 2017 at 7:58am

You are definitely setting your output as a list, which is a problem: DA.SetDataList(0, tree); This should instead by DA.SetDataTree(0, tree); Plus, you'll need to make sure your GH_ParamAccess output is registered as a "tree", something like:

pManager.AddGeometryParameter("Output Geometry", "G", "Data tree of geometry", GH_ParamAccess.tree);

Permalink Reply by jc on September 8, 2017 at 11:40am

The output set to list was exactly the problem, don't know how I missed that. Seems so obvious now. Thanks man!

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