creating an accurate topographic map

Generating contour lines from a 3d terrain

 
 

The playable area of the game world is 4x4km.

 
 

I scale the same map player uses to match the terrain size. Then I can ensure that everything is perfectly accurate.

 

Like everything else, the development of the map has been an iterative process. There are many ways to derive a topography from a 3d terrain - the key is finding a way to do that suits my current skill set and allows for flexibility. If I want to change the terrain for gameplay purposes, how tedious will it be to update the map?

A few methods I tried:

  • Create a node network in World Machine to generate contour lines per every ten meters elevation gain.
    Pro’s - theoretically it’s possible.
    Con’s - no way to be precise about intervals and confusing workflow.

  • Export 3d terrain from World Machine and manually slice it up in Maya at precise increments. Assign unique materials to each slice and bake out a color map in Marmoset Toolbag.
    Pro’s - precise.
    Con’s - tedious as hell.

  • Create a procedural material in Unreal that displays contour lines at precise interval, then use Render to Texture tool to output image.
    Pro’s - precise and flexible.
    Con’s - had to hire an expert to figure this out, and because accuracy of the contour lines depends on terrain resolution, it does become slow to do iterative work.

In the end the simplest and most flexible workflow I found was thanks to the fantastic software World Creator.

World Creator has a built-in feature that visualizes topology as different bands of color. You can set intervals for the bands, colors, and so on. Then you can output this as an image file.

A manually sliced up mesh terrain, baked with a material ID map in Marmoset Toolbag.

Rainbow topology image output from World Creator.

Easy, right? The trade-off of course is that World Creator cost a few pennies. But the many hours of tedious work saved plus the flexibility it has offered my workflow is well worth the price.

With the rainbow topology, you can easily select layers in photoshop and start creating your contour lines. But it’s important to not delete those pretty colors - they come in handy when you got to go through and add elevation markers!

Contour lines processed in photoshop from the rainbow image.

Processing in Photoshop.

Well, so much for the map. It’s been a journey, but I’ve settled on a pretty efficient workflow at this point. Creating new terrains and new maps to go along with them in the future should be a painless process now that I’ve tested so many different methods.