When developing Grasshopper components, we need to make reference to two Grasshopper Dlls: Grasshopper.dll and GH_IO.dll. These provide the GH_Component class, which custom components inherit from, as well as providing other useful Grasshopper functions.
Grasshopper.dll and GH_IO.dll
The exact location depends upon your particular Rhino installation. On my computer, I found them buried within the AppData folder at:
Within this folder, I found a large collection of files, including Grasshopper.dll and GH_IO.dll.
A similar path may exist on your computer. If you can’t find anything like it on yours, you can look up the folder through Rhino: (from David Rutten)
- Start Rhino
- Run the _PluginManager command
- Locate Grasshopper in the list of plugins
- Open the properties for the Grasshopper plugin
- At the bottom of the Properties window there’s a ‘File name’ entry
- This points to GrasshopperPlugin.rhp, which is sitting next to Grasshopper.dll
You may need to widen the window to see the full path.