Rhino3D Grasshopper: Retrieve Data Tree Branch

In Grasshopper you can retrieve branches from data trees with Tree Branch. This works with a single branch and also with a set of branches.

For a good introduction on Grasshopper’s Data Trees read this page from TU Delft.

New to Grasshopper? I suggest you read this article in the first place.

Need more learning resources? Check this out.

Disclaimer

As you will see in my screenshots most components carry a title above them displaying their name. This is because I use a plugin called Bifocals.

Also you’ll see my Grasshopper tab titles abbreviated because there’s not enough horizontal space. I will mention the titles in full in my script though.

Branch and Path mean the same thing. That’s Grasshopper data tree jargon. Put in other words, branch equals path.

Create a Triangular Grid

Let’s take a Triangular grid pattern as an example:

List Item

Let’s assume you want to retrieve one of the triangles. When you connect a List Item to TriGrid’s output you’ll see that it provides a whole set of triangles instead:

A Panel reveals that indeed List Item extracts not 1 element (= 1 triangle) but 1 out of each branch of our TriGrid data tree:

(The number of items in each branch differs according to TriGrid’s input.)

As you see, List Item by itself doesn’t work here.

Tree Branch

We want to single out 1 branch of our tree. To do this, we choose Tree Branch:

Connected to TriGrid’s output is demands for a P (ath) input:

Double-click on the canvas, write “0;0;0” and hit Return:

Feed this panel into Tree Branch’s P input:

As you see Tree Branch retrieves 1 branch (in my example the first of them).

When you connect your List item to  B output you will have extracted exactly 1 triangle:

Extract Set of Branches

To retrieve more than one branch, double-click your text panel feeding Tree Branch’s P input and simply add more paths:

Don’t forget to turn your panel in Multiline Data mode your panel should look like this:

For a good introduction on Grasshopper’s Data Trees read this page from TU Delft.

New to Grasshopper? I suggest you read this article in the first place.

Need more learning resources? Check this out.

© Horst Sondermann 2019 // All Rights reserved