Grasshopper.dll in own plugin?

I have a question,
Is it possible and legal to use a Grasshopper.dll in my own rhinocommon Plugin. I want to use some good algorithms contained in this library.


Not sure if it is legal, but why not just have users download Grasshopper? In the future (currently in RhinoWIP), Grasshopper will ship with Rhino, so all Rhino users will have it if they have Rhino installed.

It is not entirely clear to me whether that would or would not be allowed from the Grasshopper specific license agreement, but I’m coming down on the ‘is not allowed’ side. For Grasshopper in Rhino6 this agreement was removed and GH is now considered to fall underneath the same license agreement as Rhino6, which certainly does not allow this.

However when it comes to distributing dlls part of GH 0.9.0076 or earlier, the license states that:

You may not rent, loan, lease, sell, sublicense, or otherwise transfer all or any portion of Grasshopper, or any rights granted in this Agreement, to any other person without the prior written consent of RMA.

And I think that what you’re looking to do fall under either sublicense or otherwise transfer, for which you need written consent from us. I’m not going to draft any official documents, some of the legal eagles in the Seattle office will have to do that.

I think Luis’ suggestion is the best, it sidesteps any legal problem, and --in my opinion far more important-- it sidesteps versioning problems. If people install Grasshopper separately you won’t run into problems with different versions of the same dll competing for precedence.

I understand, that is, the user must install the Grasshopper to be able to use my plugin (If my plugin will use Grasshopper.dll assemby).
Maybe I misunderstood but whether in Rhino6 it is no longer possible to use Grasshopper.dll?

That’s not correct. Any plugin to Rhino (or even external application) is more than welcome to load and use any of the assemblies that are installed as part of Rhino. What is not allowed is that you distribute assemblies that are part of Rhino to people, especially people who have not bought a license for Rhino.

In Rhino6, GH is always available because it’s included in the Rhino6 installer, and you are always welcome to reference it in your own project and use it.

Thanks David,
I understand.