A Specialized Tool
Terragen, made by Planetside Software, is built for one job: generating 3D landscapes and physically simulating light and atmosphere. It produces photo-real renders of natural environments - mountains, valleys, deserts, cloud-filled skies - and has held a place in 3D matte painting for years on the strength of that specialization.
Unlike a generalist package like Houdini, Maya or Blender, every component in Terragen - terrain, surface shaders, cloud system, atmosphere engine - is built around a single goal: maximum atmospheric realism. That focus is also its limit. Terragen sits inside a pipeline; it doesn't try to cover the rest of production.
Four things stand out: an atmospheric simulation few tools match, terrain generation with no practical scale limit, an ecosystem system that populates millions of instances with automatic LOD, and a VFX-ready pipeline - multi-pass EXR, heightmaps, HDRI skydomes, broad compositing and DCC compatibility. The free version is fully capable for learning and testing (capped at 800×600); Professional unlocks unlimited resolution, network render nodes and full export options.
Interface and Node Workflow
The interface splits into three areas: a real-time 3D Preview for navigating the scene and framing a camera before committing to a render, a Node Network where every element - terrain, shaders, atmosphere, objects, functions - is built as an interconnected, non-destructive node graph, and a Render View for progressive rendering, region previews and high-res output.
The node graph organizes into five families: Terrain (heightfields, displacement, erosion), Shaders (surfaces, rock, water, snow), Atmosphere (sky, clouds, sun, lights), Objects (external geometry, instancing) and Functions (fractals, noise, color adjustments). Masks and blend modes give precise control over where each element shows up, and because everything is parametric, the same scene can be pushed into countless variations by changing numeric values.
Production Pipeline
A Terragen project moves through six stages, though rarely in a strict straight line - going back to adjust terrain after the atmosphere is set, or recomposing the camera after populating vegetation, is normal, and the procedural approach makes those loops cheap: Terrain (base heightfield and overall landscape shape), Texturing (surface shaders distributed by altitude and slope), Atmosphere (sky, clouds, sun setup), Population (vegetation and object distribution), Camera (composition and, if needed, animated path), Render (quality settings and final export).
Terrain can come from two directions. Pure procedural - fractals, noise, warp shaders - gives total flexibility and infinite variation, well suited to stylized, sci-fi or fantasy environments with no real-world counterpart. Real data - GeoTIFF heightmaps, satellite DEM (SRTM, ASTER), photogrammetry scans, high-precision Lidar - gives exact real-world accuracy, essential for geographic reconstructions or extending a real location in matte painting. The two combine well: import a real heightmap as a base, then refine it procedurally to add detail or fix problem areas.
Terrain Creation
Two entry points create a terrain: Heightfield Generate builds one procedurally from fractals (Perlin, Ridged and others), with scale, roughness and seed controlling the overall shape - the standard starting point. Heightfield Load imports an external file - PNG and 16-bit TIFF, Terragen's native TER format, RAW, or georeferenced real-world data - and several heightmaps can combine into a hybrid terrain.
Once a base terrain exists, three tools refine it: Displacement Shader adds fine procedural detail on top of the existing heightfield without touching the source - essential for detail close to camera. Warp Shader deforms the geometry for organic variation, useful for dunes or twisted rock formations. Erosion simulates realistic hydraulic and thermal erosion, one of the most important nodes for a convincing mountain or canyon.
Typical terrain recipes: alpine mountains use a Ridged Fractal base with high roughness and amplitude, sharp peaks, deep valleys, and erosion for credible ridgelines. Arid desert and dune terrain uses smooth, low-frequency fractals with warp shaders for soft, flowing undulation and minimal erosion. Eroded canyons stack horizontal layers to simulate geological stratification, with heavy hydraulic erosion carving dry riverbeds and stratified cliffs. Gentle plains and hills use low-amplitude fractals for soft variation - a good base for dense vegetation and wide horizons.
Surface Shading
Terrain materials stack as surface layers - each one a different material (rock, dirt, grass, snow, sand) controlled by a mask defining where it appears, with blend modes for gradual transitions between them. Distribution is automatic and geographic: altitude (snow at peaks, dirt in valleys), slope (rock on cliffs, grass on flats), orientation (moss favors the shadier north-facing side), and cavities (sand and sediment collect in low spots) - producing believable distributions without manual painting.
The Default Shader is the terrain's base layer, controlling color, roughness and displacement - the mandatory starting point of any scene. Surface Layer stacks additional materials on top, maskable by many different functions, with no practical limit on how many layers you stack. Water Shader gives a physical water plane with procedural waves, reflection and refraction, positioned at a fixed altitude.
Procedural texturing (fractals, noise) gives infinite variation with no visible repeat and automatic altitude/slope-driven detail, but can look systematic; image maps give photographic realism and precise control, at the cost of visible tiling risk and UV management. In practice, the strongest workflow combines both - a procedural base for variation, image maps layered on top for specific photographic detail. A typical mountain shading setup stacks four layers: a grey-rock Default Shader base, dirt and grass masked below a 30° slope, snow masked above 2000m altitude, and moss masked to north-facing, damp zones.
Atmosphere and Lighting
Atmosphere is Terragen's signature feature and the main reason it holds a place in VFX pipelines. The engine simulates real physical phenomena: Rayleigh scattering (light scattered by air molecules - responsible for a blue daytime sky and orange sunrise/sunset tones), Mie scattering (light scattered by larger particles - aerosols, pollution, mist - producing the characteristic haze over distant landscapes), and atmospheric absorption (light attenuating with distance, giving the gradual contrast falloff toward the horizon). This is genuine physical simulation, not an artistic approximation, and it's what separates Terragen skies from ones built with a purely artistic approach.
Sunlight is the primary light source, positioned with astronomical precision (latitude, longitude, date, time), producing volumetric soft shadows and a color temperature that shifts realistically with elevation angle. The Atmosphere node is the procedural physical sky, controlling density, atmospheric thickness and automatic sunrise/sunset, with sun, moon and stars built in for night scenes. Cloud Layers are true 3D volumetric clouds - stratocumulus, cirrus, cumulus and others - with density, altitude and coverage parameters, and built-in wind animation for moving sequences.
Controllable atmospheric parameters include density (altitude and thickness of the atmospheric envelope), haze intensity, sun position and intensity, and adjustable sky tones. Time-of-day presets range from a clear midday (sun at zenith, minimal haze, hard light) through golden hour (low sun, warm gold tones) and sunset (intense oranges and reds) to night (moonlight, stars, cool blue tones); weather presets range from clear (low haze, maximum visibility) through misty (high haze, soft diffuse light) and stormy (dense clouds, low dramatic light) to desert dust haze with hard, warm light. Beyond the sun, Spot/Point Lights cover artificial night or interior sources, Area Lights give soft large-surface fill, and HDRI Domes provide 360° image-based lighting from external HDR captures.
Population and Ecosystems
Terragen's population system distributes millions of 3D object instances across a terrain procedurally - the same principle as scatter systems elsewhere: a source object is duplicated many times, with position and attributes driven by terrain masks and randomization. Memory stays manageable because instances aren't stored individually - their positions are computed on the fly, which is what makes very high densities practical at all.
Distribution is controlled by density (instances per square meter), altitude range (min/max elevation where instances appear), slope preference (flat vs. inclined terrain), and exclusion masks (roads, rock outcrops, or any custom no-go zone). Trees import as OBJ geometry (SpeedTree assets are supported), with automatic size/rotation variation to avoid repetition and distance-based LOD. Grass and plants use high-density billboards, mixed multi-species populations, built-in wind animation and procedural color variation. Rocks and props scatter as procedural boulders or custom 3D imports, with randomized scale and rotation to avoid a uniform look.
Performance relies on LOD (full geometry near camera, low-poly or 2D billboards past a distance threshold, with smooth automatic transition) and culling (nothing outside the camera frustum renders, a max-distance cutoff drops far instances entirely, and terrain occlusion skips vegetation hidden behind hills). Assets come from Terragen's own basic library, third-party packs (Plantkit and similar commercial vegetation libraries), or custom OBJ/FBX imports from any 3D package.
Rendering and Output
Terragen's renderer is a full physical ray tracer: complete ray-traced reflections, refractions and shadows, true global illumination for realistic indirect bounce lighting, volumetric subsurface scattering for light interacting with clouds and fog, and the atmospheric engine integrated directly into the render calculation. It's optimized for multi-threaded CPU rendering, Professional adds networked render nodes for farm distribution, and the progressive render lets you watch the image resolve.
Detail/Quality ranges from 0.25-0.5 for a fast preview (minutes) through 1 for standard production up to 2-4 for ultra-high quality. Anti-aliasing runs from 2-4 samples for an acceptable preview through 6-9 for production quality up to 12-16 for maximum quality. GI Quality controls indirect-lighting bounces and samples - higher values give more realistic soft shadows and ambient occlusion at a real time cost. A rough guide: Draft (0.25 quality, 2-3 AA) takes minutes, Preview (0.5, 4 AA) around half an hour, Production (1, 6-9 AA) several hours, and Ultra (2+, 12+ AA) considerably longer.
Output formats cover EXR (32-bit HDR, multi-pass - the production and compositing standard), TIFF (16-bit, for archiving and post), PNG (lossless, for web and previews) and JPEG (lossy, preview only). Available render passes include Beauty (the full composited render), Depth/Z-depth (camera distance, for depth-of-field and fog in compositing), Alpha (transparency and masking for CG integration) and Object/Material ID (selection passes for compositing).
Import, Export and Pipeline Integration
Terrain and heightmap imports cover PNG/TIFF/TGA (8/16-bit grayscale), GeoTIFF (georeferenced, GPS-tagged), Terragen's native TER format, raw heightfields (RAW, BT), and satellite DEM data. Object imports cover OBJ (with MTL materials), FBX, LWO and legacy 3DS - but Terragen only handles static geometry for imported objects; animation on imported meshes isn't supported.
Exports cover multi-layer EXR with passes, 16-bit TIFF sequences, and web-ready PNG, at unlimited resolution in Professional; decimated OBJ terrain meshes, TER/TIFF heightmap exports, and baked displacement/normal maps for use elsewhere; and 360° HDRI skydomes, IBL lighting maps and cubemaps for game engines, all in 32-bit HDR EXR.
Toward compositing (Nuke, After Effects, Fusion), multi-pass EXR is the standard handoff: beauty for the final image, depth for fog and depth-of-field, alpha mattes for CG integration, and separate sun/sky/terrain passes for fine control downstream. Toward 3D packages (Houdini, Maya, Blender): a decimated OBJ terrain as geometric base, an HDRI skydome to match lighting between Terragen and the host application, animated FBX camera data for viewpoint matching, displacement maps to reproduce terrain detail, and baked texture projections for surface assets. Toward Unity and Unreal: heightmaps for native terrain tools, splatmaps for terrain material distribution, HDRI skyboxes for real-time IBL, and optimized LOD meshes - typically after simplifying the terrain mesh, generating texture atlases, baking normal maps down from the high-res version, and exporting multiple LOD levels.
VFX Applications
In matte painting, Terragen is a reference tool for high-resolution fixed backgrounds - extending real locations, building impossible or alien landscapes, rendering at 8K and beyond, and replacing greenscreen backgrounds outright. In previsualization, the speed of putting a scene together makes it useful for environment proof-of-concept, virtual location scouting, and studying lighting at different times of day - a common point of dialogue between art direction, cinematography and VFX supervision. In virtual production, Terragen-generated HDRI skydomes serve as LED-wall backgrounds, as on-set lighting references for matching atmospheric conditions, and as IBL environments for lighting continuity.
Beyond specific shots, Terragen supports full world-building for sci-fi and fantasy productions (a consistent geography, atmosphere and vegetation per setting), fast concept-art visualization before a design is locked, and building stock HDRI skydome libraries that studios reuse across projects.
A typical professional production pass runs through briefing (art direction and reference gathering), blocking (rough terrain and overall composition), detailing (full surface shading and vegetation population), lighting (atmospheric setup and final look), rendering (high-resolution multi-pass output), and compositing (final integration in Nuke or After Effects). The tool earns its place in a pipeline by doing the one thing it does better than anything else - atmosphere and terrain - and then handing off cleanly through EXR and HDRI to whatever compositing or 3D package runs the rest of the shot.