When to use: Mismatched parameter types, constructing panel inputs, or type conversions.
Safe type casts
Lightweight type checks via parameter components:
- line ↔ polyline
- point ↔ plane
- closed polyline ↔ surface
- rectangle ↔ 2D domain
- planar surface ↔ 2D domain
- vector ↔ line
- color ↔ material
Remember: a line is two points; a plane needs origin + orientation (not three arbitrary points).
Panel textOutput (required on create / setProperty)
textOutput | Downstream data | Use when |
|---|---|---|
singleString | One string; line breaks stay inside it | Domains (0 to 1), paths, labels, any single text value |
oneItemPerLine | One list item per line | Several numbers, points, or pattern tokens — one value per row |
Examples (same panel text, different mode):
1
2
3oneItemPerLine→ list{1, 2, 3}singleString→ one string"1\n2\n3"
Python script tree/list ports
When a Python script port uses tree access, convert at the boundary with ghpythonlib.treehelpers:
- Tree input →
th.tree_to_list(x)before list-style Python work - Tree output →
a = th.list_to_tree(result)before assigning to the output
List-access ports use plain Python lists; item-access ports use single values. Full recipes and anti-patterns → python-boilerplate.md. If you see Data conversion failed from Goo to … on the canvas, run gh_get_canvas_errors for an inline treehelpers hint.
Input construction tips
- Point/vector on panel:
{0,0,0} - Domain on panel:
<start> to <end>e.g.-5 to 5,0 to 1 - IsoTrim
D: use Divide Domain² output (surface as domain) - Graph Mapper: normalized 0–1 only; user sets mapper manually
- Color/material on panel: rgba
255,105,180or255,105,180 (152)
mds/reference/data-type-guide.md / View source on GitHub ↗