Creating a Spiral Rock Formation in a Mountain Landscape
Following a discussion with Henry-Louis Guillaume from ULB (Université libre de Bruxelles) - Panorama, this piece documents the creation process behind one environment scene, generated specifically to test a set of custom-made tools: a Cloner, a Drop, and a Scatter system.
The Workflow
The journey starts with terrain generation in QuadSpinner GAEA, creating the base mountainous landscape with realistic slopes and valley formations. Once generated, that terrain gets imported into Unity, used purely as a container environment for the custom tools.
Within Unity, FAB rocks and grass from Megascans were imported and several variants created. Then comes the fun part: the Scatter tool naturally distributes rocks and grass across the terrain. The spiral pattern itself was created using the Cloner tool, which actually supports multiple different patterns beyond spirals. The final touch in Unity was using the Drop tool to perfectly align every element to the terrain's slope.
For the rendering phase, the terrain was imported as a heightmap into Terragen. The positions (as Empty objects) of the rocks and grass were also exported from Unity, and in Terragen the proxy tool re-imported the actual rocks and grass at their exact positions. After fine-tuning shaders and details, the sky and atmosphere settings were configured before rendering the final scene.
Alternatives to FAB/Megascans
If you don't want to use FAB/Megascans, Terragen's own rock objects/population and Grass Clump objects both work very well directly. The main advantage of FAB/Megascans is that the objects are already well textured, and it also gives access to the excellent plant database from Xfrog. Alternatively, you can model your own rocks using tools like Blender or Houdini - it's quite straightforward.
Grass Blade Creation
Creating blade clumps is also simple: create a polygon shaped like a blade, make a patch with some rotation and scaling adjustments. Most importantly, find good textures/colors and build the shaders around them.
A Software-Agnostic Checklist
While GAEA, Unity and Terragen were used here to test these tools, this scene can be recreated in any 3D software like Blender or Houdini - the key is having the necessary tools at your disposal. A comprehensive checklist of features your software should have to properly create such an environment:
- Noise management - at minimum, support for Perlin, Voronoi and Worley noise types
- A mask system
- Filtering tools, including erosion, sediment and similar terrain modifiers
- HeightField / Mesher - the ability to create and import terrain data
- A Scatter system with support for masks, slopes and altitude-based distribution
- An efficient instance/proxy system
- A realistic atmosphere / physical sky system
- Direct/indirect lighting (a sun system)
With these fundamental tools, similar results are achievable regardless of the chosen software platform. Terragen in particular is very strong at rendering and creating photorealistic atmospheres.
Post-Processing
The last step was post-processing, since the raw output had a slightly too bluish tint. The image was brought into Affinity to fine-tune color grading and add a touch of depth of field and blur.
Tools used: QuadSpinner GAEA, Unity, Terragen (Planetside Software), Affinity, and the custom Cloner/Drop/Scatter tools. The Cloner, Drop and Scatter tools aren't public yet, but related open-source libraries and algorithms are available at github.com/bsm3d.