How to open a grasshopper file from the same working folder as Rhino

Grasshopper
1

I want to open a Grasshopper file that lies in the same folder as my Rhino file with a Rhino button. What I have sofar is as below, it requires the full path of grasshopper which is not ideal for my case.

Command for Rhino Button:

-_Grasshopper
: Banner
: Disable
-_Grasshopper _Document
: Close
: Enter
-_Grasshopper _Document _Open “C:*full path of GH file”
: Enter

Anyone knows if it is possible to achieve this in the commandline or has used other workarounds? Thank you in advance.

2

One way to open a file is simply double-click, and both Rhino and Grasshopper will launch.

3

You need to make a python script and find the path of the open file.
But you need to know the name of the grasshopper script though.

Test this out:
(Change “grasshopperscript.gh” to your preferred file name.

### Open Grasshopper script
### by Holo 2025
# -*- coding: utf-8 -*-
import rhinoscriptsyntax as rs
import os

def openGrasshopperScript():
    ### Define the scriptname
    GHdocument = "grasshopperscript.gh"
    
    ### Check if file is saved and get document path
    documentpath = rs.DocumentPath()
    if documentpath == None:
        print("Error: File is not saved, so no path located")
        return
    
    ### Combine the path and the document name
    filepath = chr(34)+documentpath+ GHdocument+chr(34)
    print filepath
    
    ### Run the grasshopper stuff
    rs.Command("-_Grasshopper _Banner _Disable _Enter", False)
    rs.Command("-_Grasshopper _Document _Close _Enter", False)
    rs.Command("-_Grasshopper _Document _Open "+filepath+" _Enter", False)

openGrasshopperScript()

Pop this in a button like this:

_-RunPythonScript (
Paste here
)

4

And here is a more advanced version that checks all files in the directory of the current Rhino file.
If none it ends, if only one it uses that and if multiple it presents a list.

### Open Grasshopper script
### by Holo 2025
# -*- coding: utf-8 -*-
import rhinoscriptsyntax as rs
import os

def openGrasshopperScriptMultiple():
    
    ### Check if file is saved and get document path
    documentpath = rs.DocumentPath()
    if documentpath == None:
        print ("Error: File is not saved, so no path located")
        return
    
    ### Make a list of grasshopper files in that directory
    list = []
    for file in os.listdir(documentpath):
        if file.endswith(".gh"): list.append(file)
    
    ### If no GH files then return
    if len(list) == 0:
        print ("Error: No grasshopper files in directory")
        return
    
    ### If only one GH file then use this one
    if len(list) == 1:
        GHdocument = list[0]
    
    ### If multiple GH files then present a listbox to choose from
    else:
        GHdocument = rs.ListBox(list, "Choose what grasshopper definition to open", "Multiple grasshopper files in directory", 0)
        if GHdocument == None: 
            return
    
    ### Combine the path and the document name
    filepath = chr(34)+documentpath+ GHdocument+chr(34)
    print (filepath)
    
    ### Run the grasshopper stuff
    rs.Command("-_Grasshopper _Banner _Disable _Enter", False)
    rs.Command("-_Grasshopper _Document _Close _Enter", False)
    rs.Command("-_Grasshopper _Document _Open "+filepath+" _Enter", False)
    

openGrasshopperScriptMultiple()