Docofossor is designed for parametric terrain modeling and digital landscape fabrication. This getting started tutorial will guide you through Docofossor’s core features, teaching you to create parametric terrain models in Grasshopper. By the end of this tutorial, you’ll be able to import topographic data, visualize it in the Rhino viewport and save your work in Rhino and as a digital terrain model.

Whether you’re planning earthwork operations, designing landscape interventions, or exploring digital fabrication workflows, this tutorial provides the first steps for leveraging Docofossor’s capabilities in your projects.

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Preparing terrain datalink copied

The terrain modelling approach of Docofossor is based around DTM’s (Digital Terrain Model) in raster format. This is a grid-based digital representation of ground surface elevations that shows the bare earth terrain where vegetation, buildings, and other surface features are removed. 

Downloading data

You can prepare terrain data for Docofossor by downloading elevation datasets from sources like government geoportals, OpenTopography, AHN, or PDOK, then using QGIS to process and export the data as ASC grid files (recommended) or XYZ format – ensuring that XYZ point data falls on a regular rectangular grid structure for proper import into Docofossor’s grid-based system.

Docofossor can handle the *.ASC and *.XYZ file formats for loading external terrain data.

• ASC Format (recommended): ASCII grid file with a 6-line header (ncols, nrows, coordinates, cellsize, NODATA_value) followed by rows of elevation values in a regular grid structure.
• XYZ Format: Simple text file with each line containing X, Y, Z coordinates (easting, northing, elevation) as space or comma-separated values, useful for point-based elevation data. Note that the data has to fall on a regular and rectangular grid.

If you don’t have your own terrain data, you can download the example DTM below.

Background information: The [df] list

Internally, Docofossor uses a custom data structure designed for efficient 2.5D distance field calculations and boolean operations on terrain data. This format organizes topographic information into a single list (df[]) that represents a regular quad grid derived from Digital Terrain Model (DTM).

The list begins with a 10-element dimension header (dim[]) containing essential grid properties: number of columns and rows, local and global origin coordinates, and cell sizes in X and Y directions. Following this header, elevation values (lz[]) are stored in column-major order starting from the bottom-left corner of the grid, with each value representing the Z-coordinate at the corresponding grid cell center.

This format enables Docofossor to perform parametric transformations while maintaining spatial relationships and coordinate system information necessary for accurate terrain modeling and fabrication workflows within Grasshopper.

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Importing the DTMlink copied

To begin working with topographic data in Docofossor, navigate to the I/O tab where you’ll find components for importing various elevation datasets. This tab contains the essential tools for bringing external terrain data into your Grasshopper workflow, including support for common formats like ASC grid files and XYZ point data.

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Visualising the DTMlink copied

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Saving your resultslink copied

In this Getting Started guide we have not altered our topography. That part will be covered in other tutorials. For now though, it is good to know how to save changes that you will make to a new DTM.

To save your changes, Docofossor offers several output options for different workflows. You can offcourse simply “bake” your generated mesh directly into the Rhino viewport, converting the parametric geometry into permanent Rhino objects for further modeling or visualization. However, this method does not allow future editing of the DTM using Docofossor.

A better way is to use the I/O components to export your modified terrain data to standard formats like ASC grid files or XYZ point data. This will also enably you to later import and ‘bake’ your file to Rhino, but on top of that it enables future editing with Docofossor and integration with GIS software and analysis tools.