Grasshopper compatibility Rhino5 v Rhino6

Hi all,

I was wondering if the defenitions made in the latest grasshopper version for Rhino5 are compatible with the new Rhino6 version.
I’m on the point of upgrading to Rhino6, but don’t want my old grasshopper definitions to stop working.

Kind regards,


Yes, going backwards (opening files on GH/R5 made with GH/R6) is possible too provided you did not use any components that are new in R6. Unfortunately this includes some pretty basic ones like Addition, Multiplication and Subtraction.

Great! Thanks for the swift response, happy upgrading for me I guess!

It seems that Grasshopper in V5 and V6 use the same “Special folders”, and that’s a big issue for me.
In particular, if GH plugins are updated for V6 (Like Human for instance), then they will no longer work for V5 definitions.
I wish that they could be made separate to allow a smooth transition.

You can put plugins for GH/R6 into %appdata%\Grasshopper\6\Libraries\ where they will get ignored by GH/R5. But you’re right in that it’s at present not possible to hide a GHA from GH/R6. I’m working on something that would permit this.


Is that why I get a error message when loading Grasshopper in Rhino 6 ( “An error occured during GHA assembly loading:
Path: C:\Users\Tibor\AppData\Roaming\Grasshopper\Libraries\TSplinesGH.gha
Exception System.IO.FileNotFoundException:
Message: Could not load file or assembly ‘TSplines, Version=, Culture=neutral, PublicKeyToken=null’ or one of its dependencies. The system cannot find the file specified.”)? Rhino 6 reading something that pertains to Grasshopper Rhino 5 .
Could this be reason I could not upgrade Kangaroo in Rhino 6 and then Grasshopper in 5 would not even load.

1 Like

I separated my v5 and v6, with v5 in %appdata%\Grasshopper\Libraries with a no6 file, then v6 in %appdata%\Grasshopper\6\Libraries but am getting a file conflict pop up when opening grasshopper in v5. v6 works correctly

any ideas what could be going on?

i did some troubleshooting: removed the .no6 and removed the files in the 6\Libraries folder

after doing this and opening rhino6, the v5 library worked without issue in v6. Is the separation only needed for libraries that utilize changes in rhinocommon.dll v6 (or grasshopper v1) ?

Yes, it’s just to resolve conflicts. If your plugin works in both versions (as most plugins do) you only need a single instance.

I am also getting this error for T-splines as I have both Rhino 5 and 6 installed on my laptop. I was just googling for the error and found this old post, hence commenting here.

Any method/workaround yet ?

You can’t install T-Splines for R6. Autodesk will no longer develop new versions or sell the T-Splines for Rhino 6. It’s not a job for McNeel.

Okay. Any method to just get rid of the error message? I mean, make Rhino 6 just ignore the loading of T-splines?

I was wondering about this for a long time. Is there any way to update those addition, multiplication and substraction components when you open a gh made in rhino 5, in rhino 6? i find it quite ridiculous haha

1 Like

Solution -> Upgrade

I know. I have R6 but in my work they have R5, that’s where i have an issue :confused:

Pancake -> Downgrade

I’d recommend you to stick to the Rhino 5 version of arithmetic operators, though.