Dissecting Grasshopper

Daniel Davis – 31 August 2010

Afew months ago, Ben Sitler created a guide for making Grasshopper components where, tucked in the bottom, are instructions for viewing the Grasshopper source code. Download the .Net Reflector from RedGate, point it towards the Grasshopper dll, and there it all is. Dissecting Grasshopper like this is against section 3.2.1 of the Grasshopper terms of service, however just looking at the code is unlikely to draw attention, copying the code on the other-hand is both unethical and illegal.


It is fascinating to see the inner workings of production software. I was expecting it to be overflowing with elaborate geometric algorithms, graph theory and optimisations. These are definitely there but for the most part the code is user interface. This probably should not be surprising, the interface to Grasshopper is fairly sophisticated with many different buttons and controls, while the geometry is largely handled by Rhino. The dominance of interface in code seems to be true for many other projects, I used to sell small software plugins and was always amazed by how much time I would spend not writing plugins and instead packaging software, writing instructions and providing support. Adobe seems to face a similar phenomena, about 25 minutes into this talk about Photoshop at Google, the Adobe engineer mentions that the interface of Photoshop accounts for about 1/3 of the code base, surprising when you consider how simple the interface is relative to how complex the tools are. I think as a user the output of the software gets all the attention, however under the hood of production software are elaborate algorithms, not to generate the right output, but to help the user generate the right output.

Lately I have been very focused on the output of CAD software, and whether software engineering can teach us how to make better parametric models. I wonder if I have this the wrong way around, perhaps you need to start with the interface.

3 August 2010: Removed the sentence that stated: “David Rutten, the developer of Grasshopper, has mentioned that decompiling code like this is often against the terms of service, but I can not deduce if it is against the Grasshopper terms of service – I think as long as you are just looking and not taking anything, it should be fine.” And replaced it with a sentence referring to the Grasshopper terms of service, thanks to David Rutten for clarifying this in the comment below.