The Wonders of Terragen 2 - A Case Study in Displacement Magic

- by FrankB -

Chapter 1 - Made of Clay

This is a short case study about Planetside Ltd.'s amazing 3D Landscape Renderer called Terragen 2. When you read the description of what Terragen 2 really is on Planetside's website, you'll stumble over the following bullet point:

Hybrid micropolygon renderer optimised for large displacements and very large landscapes.

And in this case study, we'll be discovering what this really means. We start with a horribly undetailed DEM (Digital Elevation Model) of the Horseshoe Bend area.

Like is was made of clay, this terrain has no interesting detailed feaures whatsoever - it's just a simple and rough representation of the real Horseshoe Bend terrain. Over the course of this case study, we are going to make use of Terragen's unparalled hybrid micropolygon renderer and add an absolutely insane amount of completely procedural detail to this grey and boring scene.

On a side note: because of the procedural nature of every of the following modifications, the project file for the scene remains only a handful of kilobytes large (excluding the DEM data, of course).

Chapter 2 - Adding Random Coarse Detail

Ok, so the larger terrain features need to be a little more detailed. At the moment, the terrain has very dominant rounded shapes, which are a coming from the interpolation of distinct height samples, that the DEM data is providing us with. Now, in order to prepare the terrain for some interesting and detailed outcrops later on, we are going to add a few bumps and ridges. Gently, because we don't want to completely change the overall proportions of the terrain.

So we're adding relatively coarse bumps and displace the terrain into all 3 dimensions. Just a bit.

Alright, so this has provided us with a little bit more variety, with terrain features of an approximate size that the satellite scan resolution of the real world terrain may have omitted. But is still has a long way to go. Let's go to the next level of detail. We're going to hack away some of the landmasses to prepare for some really nice strata.

Again, all procedurally. At no point during the development of this image, we go into any third party app to modify the terrain. We only use Terragen's built-in displacement "engine" to intelligently apply terrain modifications that work the same way at any point on our virtual globe.

So does this look more like a real world canyon? Yes Sir, but still a long way to go. Let me spend a few words on that: "a long way to go" in this case really means that we have a few more levels of detail displacement to apply. The actual development of these details only take a few minutes if one understands the program. From a production standpoint, these displacement capabilities are fantastic. No modelling, no meshes, but intelligent and versatile displacement functions, that are easy to apply and modify, until it looks right.

Chapter 3 - From Same-Same to Natural Variety

Now that we have the strata applied, we're amazed about how much more canyon-like and interesting this has become, but on a second look this looks still quite too CG, in these sense that every strata lines up so perfectly horizontal, and so perfectly identical - everywhere. So we are going to change that by applying a random shift to the vertical axis of the terrain. Just at the right sizes to look like random shift in the environment. This will make the strata less regular.

This change is relatively subtle, so you may need to look at both this and the previous thumbnail in full size in order to see what happened.

The same goes for another modification we'll make to the terrain. I think the terrain needs a few - just a few more large scale outcrops, but displaced only very softly, primarily on the steeper parts of the terrain.

So we are applying a few outcrops, which are generated from angular voronoi noises at a variety of scales, so that each outcrop also contains small scale cracks, that look really good with this type of scene. You'll probably notice the cracks best in the final, large render further down this case study. As I said, the following and the previous render need to be compared in full view.

So we are applyng a few outcrops, which are generated from angular voronoi noises at a variety of scales, so that each outcrop also contains small scale cracks, that look really good with this type of scene. You'll probably notice the cracks best in the final, large render further down this case study. As I said, the following and the previous render need to be compared in full view.

It's not really time for color at this point, because we are not done with the displacements yet, but hey, who can look at a grey terrain for so long and don't fall asleep? Here's some "stratified color" on the steep parts. Using Terragen's unique abilty to combine fractals for both color and displacement, we're not just covering the landscape with one single, dull color - no, we're letting Terragen 2 mix various colors and align them with the terrain features. Nice.

Chapter 3 - Insane Detail

We have so far covered detail in roughly 4 orders of magnitude, which we have applied to the grey mass of clay we have started with. Every feature sized from 1000 meters to 1 meter has been modified somewhat. Far far so good, but now we talk real detail! Let's add another 3 orders of magnitude in small scale detail! Let's cover the whole thing with millions and millions or rocks, pebble, and grains of sand! Let's try to make Terragen 2 choke and beg for mercy ....

As you can see, we have utterly failed - Terragen 2 is easily consuming our additional displacement instructions. You are looking at a crop of the entire terrain made so far, rendered 4000 px wide. No choking, no begging for mercy. Look at all this detail (the render quality chosen was only at 50%, to speed things up for the purpose of this case study. We are still in development phase, so no full render quality, yet).

Let's look at the full Huge Terragen 2 Render thing

Chapter 4 - Finishing Up

We're done with the displacement magic for this image. A few minor iterations further, some color tuning, and after adding a few grass patches and dry bushes, we'll call it a day and let the final render speak for itself. Thanks for joining us on this tour on New World Digital Art - http://www.nwdanet.com - Your #1 Terragen 2 Resource on the web.

CLICK HERE for a full size version of the final render (3000px wide)

On the left side you see a screen grab of the final Rock Wall Pack Product, available through this site soon. A lot of the magic is in the internal networks of the shaders, so this image is just to demonstrate that the preset itself is relatively easy to use and integrate in your custom scenes.

Last Updated on Monday, 08 February 2010 19:31