Castor

Grasshopper plugin · v1.2.5 · updated 9/2/2026

Castor is a free toolkit developed for working with topography. Current features include mesh generation tools for building topography from contours and/or GeoTIFFs; hydrology tools to define drainage network, flow accumulation, and catchments; topography analysis tools for landform classification, viewshed analysis, and relative elevation; and grading tools to modify curves and meshes. Future development will include additional GIS methods and tools to support Nature-based site design.

Install in Rhino Download .yak Website Open in directory

Total downloads: 2,145
Recent downloads: +44 / week+188 in the last month
Latest version: v1.2.59/2/2026
Releases: 9every ~55d
First released: 6/19/2025
Download size: 325 KB
License: Not declared
Authors: Conner Corbett

Compatibility

How to install Castor

Click Install in Rhino to open Rhino's Package Manager with Castor selected, or run _PackageManager inside Rhino and search for Castor.

Or install it from a terminal (assumes a default Rhino 8 installation):

Windows (PowerShell)

& "C:\Program Files\Rhino 8\System\Yak.exe" install Castor

macOS (Terminal)

"/Applications/Rhino 8.app/Contents/Resources/bin/yak" install Castor

Or download the .yak file above and drag it onto an open Rhino window.

Restart Rhino once the install finishes.

Download trend

1,787 downloads on 2026-07-13 → 2,145 on 2026-10-07

Castor version history

Date	Version	Builds	Downloads
9/2/2026	1.2.5	Windows & Mac · Rhino 8.0	295
5/19/2026	1.2.4	Windows & Mac · Rhino 8.0	348
2/28/2026	1.2.3	Windows & Mac · Rhino 8.28	217
1/13/2026	1.2.2	Windows & Mac · Rhino 8.14	339
1/4/2026	1.2.1	Windows & Mac · Rhino 8.14	96
11/5/2025	1.1.3	Windows & Mac · Rhino 8.14	191
9/18/2025	1.1.2	Windows & Mac · Rhino 8.14	179
8/28/2025	1.1.1	Windows & Mac · Rhino 8.14	71
6/19/2025	1.1.0	Windows & Mac · Rhino 8.14	107