3D Modelling from Contours: How to Create a TIN in ArcGIS

Have you ever seen a 3D landscape in a movie or a video game and wondered, “How do they make that?” What if you could build your own, not from imagination, but from real world data?

Welcome to the exciting world of 3D modelling in geography. This isn’t about fantasy dragons; it’s about using technology to understand our planet in a whole new dimension. Today, we’re going on a digital adventure. We’ll take a boring, flat file, turn it into wiggly lines called contours, and finally, transform it into a stunning 3D mountain you can explore on your screen.

The best part? We’ll be creating a specific kind of model: a 3D modelling of contour generated with TIN.

Our 3D Modelling Mission: Step-by-Step

Our goal is clear: build a 3D model of a landscape. Here is our game plan, from start to finish.

1. Find Our Raw Material: Get a DEM
2. Draw the Blueprint: Convert the DEM to Contour Lines
3. Build the 3D Frame: Generate a TIN from the Contours
4. Explore Our Creation: Visualize and Style the 3D Model

Step 1: Find Our Raw Material – Get a DEM

First, we need the foundation of all our work: a DEM.

What’s a DEM?
DEM stands for Digital Elevation Model. Think of it as a spreadsheet where every cell contains a height value instead of a number or a word. When mapped out, these cells create a perfect, digital representation of the ground surface hills, valleys, and all.

How to Get One:

1. Go to a website like USGS EarthExplorer and Register (it’s free).
2. Type in the name of your area (like a local mountain or park) or click on the map to mark your spot.
3. Under “Data Sets,” look for Digital Elevation > SRTM or ASTER Global Digital Elevation Model. These are satellite-based DEMs that cover most of the Earth.
4. Select and download the file for your area. It will usually download as a .tif file.

Step 2: Draw the Blueprint – Convert the DEM to Contour Lines

Now, we’re going to trace the shape of our landscape. We do this by creating contour lines from the DEM.

What’s a Contour Line?
A contour line is a line on a map that connects points of equal height. If you walk along a contour line, you would never go up or down you’d stay at the same elevation. Close together lines mean a steep slope; lines far apart mean gentle terrain.

Let’s Make Them in ArcGIS Pro:

1. Open ArcGIS Pro and create a new Map project.
2. Add your DEM file by simply dragging the .tif file from your folder into the map window. You’ll see a colored, flat-looking image. This is your DEM
3. Now, click on the Analysis tab at the top and then click Tools to open the Geoprocessing pane.
4. In the search bar of the Geoprocessing pane, type “Contour” and select the tool that appears.
5. It’s time to set up the tool:
   • Input Raster: Click the dropdown and select your DEM layer.
   • Output Feature Class: Name your output file, like My_Contour_Lines.
   • Contour Interval: This is the height difference between one contour line and the next. For a good level of detail, let’s set this to 25 (meters). This means a new line will be drawn every 25 meters up the mountain.
6. Click Run. Watch as the tool draws all the contour lines over your DEM. You now have a classic topographic map1

Step 3: Build the 3D Frame – Generate a TIN from the Contours

This is the coolest part. We’re going to connect those lines to create a 3D skin for our landscape using a TIN.

What’s a TIN?
TIN stands for Triangulated Irregular Network. It’s a fancy name for a simple idea: it connects the points from your contour lines with tiny triangles. Because each point has a height, the triangles form a bumpy, continuous 3D surface. It’s like wrapping your landscape in a mesh of geometric shapes.

Here’s How to Create It:

1. In the same Geoprocessing pane, search for the tool called “Create TIN”.
2. Now, configure the tool carefully:
   • Output TIN: Give your 3D model a name, like My_3D_Mountain_TIN.
   • Coordinate System: Make sure this matches your map. ArcGIS will often suggest one for you.
   • Input Feature Class: This is the most important part. Click Add a New Feature.
     • In the new row that appears, click the dropdown under ‘Layer’ and select your My_Contour_Lines layer.
     • Under ‘Height Field’, select the attribute that stores the height data. It will likely be called “Elevation” or “Contour”.
     • Under ‘Type’, make sure “Mass Points” is selected. This tells the tool to use the contour lines as sources of height points.
3. Click Run. The tool will now build your 3D model. When it’s done, you’ll see a new, solid-colored layer in your Contents pane. This is your TIN.

Step 4: Explore Our Creation – Visualize and Style the 3D Model

Your TIN is 3D, but you’re still looking at it in a 2D map. Let’s step into the third dimension!

1. At the top of your screen, click on the Map tab.
2. Click the arrow under “Convert” and choose “To Local Scene”.
3. Your view will change instantly! You can now:
   • Rotate: Hold the V key and drag your mouse to spin the model around.
   • Tilt: Use your mouse’s scroll wheel to tilt the view.
   • Pan: Hold the C key and drag to move around.

Make it Look Real:
Right now, your TIN is probably one solid color. Let’s make it look like real earth.

1. Click on your TIN layer in the Contents pane.
2. Under the Appearance tab, click on Symbology.
3. Instead of “One Color,” change it to “Elevation”.
4. Now, you can choose a color ramp. Pick a green-to-brown-to-white ramp to make it look like a realistic mountain with vegetation, soil, and snowy peaks.

What Did We Just Achieve?

You just completed a professional 3D modelling workflow. You started with raw elevation data (a DEM), created a traditional map product (contours), and then used advanced GIS techniques to build a 3D modelling of contour generated with TIN.

This TIN model isn’t just for looks. Scientists use it to study erosion, city planners use it to decide where to build, and game developers use it to create realistic worlds.

Loved this guide? Check out our next tutorial on How Geospatial Solutions Shape Urban Planning.