Isohypsen Plug For Rhino3d

Table of Contents

The Plugin

What the plugin does

The plugin is designed to assist with data preparation for “classical” landscape models. Thereby creating a specific workflow to minimize repetitive tasks. 

What the plugin doesn’t do

The plugin doesn’t take any design decisions for you, nor does it help you find the proper level of abstraction for your model. Keep in mind that cadastre data is especially troublesome and needs to be redrawn because of it’s poor quality. As of today, there is no magical “improve” bad drawings button, that takes away the redrawing step that will safe you a ton and frustration in the digital workshop.

The Rhino Commands


Cleans the layer structure of the GEOBAU Format for better orientation.


Trims all selected lines to a given boundary/model perimeter. 


Creates the topographic model by projecting surfaces to the contour lines. At the same time the contour lines get smoothed and a point reduction happens that improve the data for digital fabrication.


Creates a 2D-layout with labels ready to be exported for laser cutting, the cutting plotter or milling. Each contour layer has trimmed cadastre data to minimize production time and a guide line of the top layer that can be used for assembly.


Step by Step 

  1. Make sure to download both .dxf files of your map section. Click here to find out more. 
  2. Open a new rhino file > “Small objects in meters”
  3. Import both .dxf files. Set model units and layout units to Meters.
  4. Type “SelAll” in the command bar and zoom to your selection by klicking Zoom > “Zoom Selected” in top view to see your drawings.
  5. Type “Isohypsen_layers” in the command bar and confirm with ENTER to clean layers. 
  6. Type the following in the command bar to remove all blocks. Confirm Every Step with ENTER:
    • SelBlockInstance
    • Explode
    • Join
  7. Type “SelDup” in the command bar and delete the duplicates.
  8. Use the rectangle tool to draw the boundary.
  9. Type “Isohypsen_boundary” in the command bar and follow the instructions to trim the selected boundary area. There are two steps to complete the task:
    • select curves to split: Type “All” in the command bar and confirm with ENTER.
    • select boundary: select your previously drawn boundary.
  10. Select all Drawings, type “Move” in the command bar and follow the instructions to move your drawings to the 0, 0, 0 coordinates.
  11. The imported cadastre_data must be redrawn now to optimize laser cutting. Use Polylines and NURBS curves for better results.
  12. Use Units to  reset the units from meter to millimeter and check that your scaling is right. If you need to adjust your scaling use Distance to check the actual length and Scale to set the new scale
  13. Once done, move the terrain curves below the cadastre drawing sets.
  14. Generate the contour surfaces and simplify the contour lines by typing “Isohypsen_init” in the command bar and following the instructions. There are four steps to complete the task:
    • select contour lines. Press enter when done: “Höhelinien” > “Select Objects”, press ENTER
    • select boundary: klick the previously drawn boundary 
    • reduce point count to 0.5: press ENTER
    • select objects to trim, select pressing Shift to extend: follow the video below from 04.47 if unclear.
  15. You can now cut out the outline of your buildings out of the iso surface. Therefore type „Trim“ in to the comman bar. There are two steps to complete the task:
    • select cutting objects: select the outline of the building you want cut out of the iso surfaces. Press ENTER to confirm your selection.
    • select object to trim, select pressing shift to extend: select the outlines of the surfaces you want to cut. Press ENTER to confirm.
  16. Type „isohypsen_layout“ in the command bar and follow the given instructions to generate the cutting data.
  17. Create a new layer and draw a rectangle with the size of your stock to arrange/nest the cutting data
  18. Use Print to export a vector PDF for the laser cutter or save the rhino-file to import it into the zünd template

Installation And Download

The plugin is designed to work with Rhino7 on Windows. It can be installed on a Mac with a bit of extra work (see below).
To install the plugin on your computer simply download isohypsen.rhi to your computer and double-click the installer while Rhino3d is closed. Open Rhino3d after the installation is complete and the commands of the plugin should be available when you type “isohypsen_…” in the command line. 
Please download the files for the plugin from our github repository and follow the official installation instructions on the rhino developer site:

Note: Sometimes, using this system, Rhino requires that Python be loaded before it can see the new command for the first time in a session – running EditPythonScript, or any other python script should allow the command to work.


If you want to contribute to our plugin with your own ideas or you know how to improve the code, feel free to help us maintain and improve the plugin.


This is a shout out to all the kind help that we received while investigating this topic. 

The basic idea for the workflow comes from an explanation of a similar plugin that is being used in the education of architectural model builders in Switzerland and was kindly explained to us by Noa Hirschi from

Further explanations on the  aesthetics and design considerations as well as much needed insight into the different data sets were provided to us by Pascal Gnädinger from

Federico Bertagna from the Chair of Structural Design at ETH Zurich was kind enough to develop the first a fist draft of the plugin with Grasshopper