Bison v0.9 Beta: Landscape Plugin for Grasshopper + Rhino 6

Bison is a landscape architecture plugin for Grasshopper + Rhino 6. It features tools for terrain mesh creation, analysis, editing, and annotation.

It focuses on a continuous workflow from mesh analysis to editing and works to keep components concise and intuitive. The analysis tools include slope and aspect visualization, cut/fill calculations, watershed modeling and more, while the editing components transform the mesh based on curves and points. Bison also includes tools for importing landscape meshes, triangulation, and resampling, as well as components for annotating plans and cutting sections.

It is currently in it’s first beta release. Please visit for a download link and component documentation.


I don´t understand how can Install the ghpy File into the Download Folder!!!

Thanks in advance

Best regards

You can install the plugin by following the Grasshopper drop-down menu to File > Special Folders > Components. Save the ghpy file here and it should be loaded automatically.

You will need Rhino 6 to run Bison. If you get an error when the plugin tries to load, check your system for independent installations of IronPython, which may cause a conflict with GH if an older version is installed.

Hi Bison,
I wanted to test your plugin, it looks mighty useful. I was able to put the GHPY file in the Grasshopper components folder. However, upon launching grasshopper, I am getting this error. I don’t have a standalone IronPython installed. I do however have cPython installed in this machine.

Thanks for the report. This was a known issue with some installations, and has been fixed. Downloading the updated version of Bison (at the same address here) should do the trick.

Thanks for the answer,

Work with the new Update!!!

many Thanks

Thanks for the new version. This fixed the issue for me.

Hi All, A new update has been released! With some revisions for performance and stability. Download at

Thank you! I really love this plugin!
Using it for a big landscape project now and it’s working like a charm.

Why do the components have a hardcoded expiration date?

Good to hear that it’s useful for you! Would be great to see some of the work if you can post it.

There are a few reasons why the components expire, but mostly because it makes it easier to keep track of issues and updates if we know exactly what’s ‘in the wild.’ This is on a monthly schedule, especially since Bison is still in the early stages, but will be extended in the future.

Hi I was wondering what sort of algorithm the Viewshed Analysis is using, I’m asking because of some tolerance values a need to know, and these change depending on the implementation. Thanks
Has Someone Implemented Total Viewshed Analysis?

The viewshed component is a line-of-sight analysis of mesh faces from a given 3d point. This is geometrically precise down to Rhino’s tolerances, so the effective tolerance would be determined by your application and the precision of your mesh (especially the size of its faces and smoothness).

This is not a total viewshed analysis (assuming that you mean the ‘averaged’ isovist graph of all locations), but could be used to generate one depending on the scale and requirements of your project. A key difference is that the component works in the coordinate space of the model itself, rather than a rasterized grid, which is a necessary abstraction for calculating the total viewshed. This can be more computationally intensive, but allows precise and reliable results for meshes of any structure or complexity.

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Hi, thanks for this amazing development. I am currently using it in the office on some projects.
I have one question regarding the cut and fill component. Can you please explain the logic or the definition behind it? I just want to make sure the numbers coming out are somehow legit. Cheers!

Sure, happy to explain: the cut and fill component works through a 3d “area under the curve” problem. It finds a numerical solution based on the difference between the total volumes of the proposed and existing meshes. This essentially means that every point on the mesh is checked for the volume it contributes to the total (based on the size of the analysis grid), and its difference registered in both the calculation and in the colored output mesh.

So the output is an approximation based on the size of the grid, the finer the grid the more exact the result. The caveat, however, is that once the analysis grid is smaller than the mesh faces of the input, the resolution of the original mesh(es) becomes a source of error, since we can’t know the data that might be missing at that smaller scale. More generally, we have found that when using this in design practice, these calculations have been far more certain than the other variables related to working through cut and fill scenarios (soil compaction, composition, underground structures, accounting for vegetation, etc.).

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Hi All, A minor update has been posted, which will work until July 1st. Download at Happy New Year!


After doing some research, I assume that this cut fill component calculates the vector lengths between the grid of points of the proposed and existing mesh. Negative being fill and positive being cut, finding the total of both and divided to the site area, am I correct?

When i download the plugin, once inserted in the folder this is what it appears,

does anyone know how to solve this problem?

Hi @Bison - are you planning on releasing an update with extended expiry date?

I can’t get bison to load, using Rhino 6.16.19205.01052 and Grasshopper 1.0.0007 on Mac. Does anyone know how to fix this error?

Hi - the Bison plug-in has expired - so even if you were able to load it, you won’t be able to use it until @Bison publishes and updated version.