Node reference
LibreTerrain has 60 nodes. Every page here is generated from the application's own node definitions, so names, defaults, ranges and descriptions match the app exactly. In the app, hover over any setting to see the same description.
All sizes are in metres and all randomness comes from a seed, so a node looks the same at every resolution and on every machine.
Primitives
Basic shapes, hand-drawn polygons and imported heightmaps to start from.
ConeA cone with straight sides, like a simple volcano.ConstantA flat terrain at a fixed height.FileImport a heightmap image (EXR or 8/16-bit PNG), stretched over the whole world. Pixel (0, 0) is the world origin, as in exported files.GradientA ramp: a straight slope across the terrain, or a radial bowl around a point.HemisphereA rounded dome. With Height equal to Radius it is a true half sphere.PolygonsFlat areas drawn as polygons on the 2D map, each at its own height, with a soft slope around them. Block out continents, islands, plateaus and lakes, then add detail with noise and erosion.ShapeA flat-topped circle, square, diamond, hexagon or triangle with a soft edge. Useful as a mask or a plateau.
Noise
Procedural noise: the raw material for natural-looking detail.
BillowBillow fractal noise: rounded, puffy hills separated by sharp creases.Domain WarpFractal noise pushed around by other noise: swirling, folded, flowing shapes.fBmFractal noise: layers of Perlin or simplex noise at finer and finer scales.PerlinSmooth, rolling single-layer Perlin noise.RidgedRidged fractal noise: sharp, branching ridgelines with detail gathered on the crests. A good start for mountain ranges.SimplexSingle-layer simplex noise: smooth, with fewer grid-aligned artefacts than Perlin.ValueSingle-layer value noise: random heights smoothly blended. Softer and blobbier than Perlin.VoronoiCellular noise: a random pattern of cells. Feature size is the typical cell size.
Terrain
Hand-built landforms, shaped by noise, meant to be combined and then eroded.
CanyonA winding canyon with a flat floor and stepped walls, cut into the input terrain (or into flat land at Surface height).CraterAn impact crater: a bowl with a raised rim and a flat floor, placed on the input terrain (or on flat ground).DunesA field of transverse sand dunes: gentle windward slopes, steep slip faces and sinuous crests.MountainA single mountain with ridges and gullies running down from the summit.PlateauA mesa: a flat top ringed by cliffs, with a rubble slope at their foot.RidgeA long mountain ridge with a wandering crest and spurs down its sides.
Adjust
Filters that reshape a heightfield: levels, curves, terraces, blur, warps and more.
BlurSmooth the terrain. Features smaller than about the radius are smoothed away.ClampCut off heights below Low and above High, leaving flat floors and tops.CurveReshape heights with a curve. Left = the world's lowest height, right = its highest; pull the curve up to raise those heights. Heights outside the world range are clamped.InvertTurn the terrain upside down: peaks become pits and valleys become ridges.LevelsRemap heights from an input range to an output range. Gamma below 1 raises the midtones; above 1 lowers them.SharpenExaggerate detail: bumps smaller than the radius get taller and dips deeper.TerraceCut the terrain into steps: flat benches with steeper risers between them.TransformMove, rotate and scale the terrain around the centre of the world. Areas brought in from outside repeat the edge.WarpPush the terrain around with smooth noise, bending straight lines and regular shapes into natural ones.
Combine
Merge two heightfields, optionally through a mask.
Data
Masks measured from the terrain, used to drive colour, vegetation and blending.
AspectWhite on slopes facing the chosen direction (e.g. sunny or shaded sides), black on slopes facing away. Flat ground is black.CurvatureFinds ridges and peaks (convex) or valleys and hollows (concave), by comparing each point with the average height within Radius (a topographic position index, not surface curvature).DistanceA glow around the white areas of a mask: white at the shapes, fading to black at Distance away. Inside mode measures inwards from the edges instead.FlowWhere rain would run: Flow is bright along streams and rivers (the area draining through each point, on a log scale), Direction is the way water flows (0..1 = 0..360°, 0° = +X), and Basins gives each drainage basin its own value. Pits fill until they spill; water leaves at the world's edges.Height MaskWhite where the terrain is between Low and High, fading to black over Falloff.OcclusionAn approximation of how open the sky is: white on ridges and open ground, dark in hollows, creases and valley floors, by how far each point lies below its surroundings (not a traced sky view). Radius sets the size of the features that shade; small radii give a cavity map.Rock HardnessAlternating soft and hard horizontal beds. Connect to an erosion node's Rock hardness input.Select RangeWhite where the input mask is between Low and High, fading to black over Falloff.SlopeWhite where the ground is as steep as Min to Max degrees (0° = flat, 90° = vertical).WetnessHow damp the ground is, for placing vegetation: white where water collects (large drained area on gentle ground) and near water. Water is the Water mask if connected (e.g. a River, Lakes or Sea mask), plus streams. Water distance is black at the water, white Reach metres away.
Simulate
Erosion and hydrology: the nodes that make terrain look like it has weathered.
Hydraulic ErosionRivers carve branching valleys over geological time and drop their sediment where they slow down. Strength limits where it acts; hardness resists wear. Water leaves at the world's edges.LakesFills hollows with water up to the level where each would overflow. Height is the lake bed (flattened by sediment), Water surface the lake level (the ground elsewhere), Lakes is white on water and Shore along the waterline.RiversCarves river channels where the water draining through a point exceeds Source area, widening and deepening downstream. Rivers run to the world's edges, crossing hollows at their spill level. Outputs the carved Height, the Water surface, the River mask and a Riverbank mask.SeaFloods the terrain below Sea level from the world's edges and wears the land just above it into beaches. Outputs the coast-worn Height, the Water surface, the Sea mask, a Shallows mask (fading with depth) and a Shoreline mask.SnowSnow settles above the Snow line, lower on slopes facing away from the sun, and slides off cliffs; Melt clears thin snow first. Outputs the snow-covered Height and the Snow mask.Thermal ErosionMoves loose material down slopes steeper than the talus angle. Strength blocks transfer; hardness resists shedding.
Colour
Colour maps, built in the Colour tab.
Blend ColoursPuts Top over Bottom where Mask is white (everywhere without a mask), with the chosen blend mode and opacity.ColouriseColours a mask or height through a gradient: black (or the lowest height) takes the left end's colour, white the right end's. Use it on Slope, Aspect or Height Mask for colour by angle, facing or altitude.Colour ImageImports a colour image such as satellite or aerial imagery (PNG, JPEG or EXR), stretched over the whole world. Pixel (0, 0) is the world origin, as in exported files.Colour LayersQuick material layering: each connected layer is painted over the ones below it where its mask is white (everywhere without a mask), in order 1 to 4.
Output
Engine-ready textures: splat maps, packed masks and normal maps.
Normal MapA normal map of the terrain for texturing: red = east (+X), green = up the image (OpenGL: Godot, Blender, Unity) or down (DirectX: Unreal), blue = out of the ground.Pack Masks (RGBA)Packs up to four masks into the red, green, blue and alpha channels of one image, values unchanged (not normalised, unlike Splat Map). Unconnected channels are 0. Export as PNG 8 for engines.Splat MapTurns up to 8 material masks into weights that add up to 1 at every point, for terrain texturing in engines. Layer 1 is the base: if it isn't connected it fills whatever the other layers leave. Weights 1-4 and 5-8 pack four layers into R, G, B and A; each weight is also available on its own.
Vegetation
Plant and debris populations, exported as density masks and point data.
Debris / RocksScatters rocks where they collect: talus below cliffs and steep slopes (or the Talus input, e.g. Thermal Erosion's Debris) and a population's Dead zones. Outputs a Density mask and one point per rock.GrassA grass population: meadows and ground cover, mostly used as a Density mask for engine grass painting. Points are clumps. Outputs as for Trees.ShrubsA shrub population: bushes and undergrowth, denser and hardier than trees. Outputs as for Trees.TreesA tree population: where trees grow (Density) and one point per tree (Points), from slope, altitude, water and earlier populations (Occupied). Dead zones marks scree and slide paths. Occupied is the ground taken (all of it from a density of 0.5) added to the Occupied input, for chaining populations.
Portal
Bring Terrain-tab outputs into the Vegetation and Colour tabs.
Height PortalBrings a heightfield from another tab (e.g. Terrain into Vegetation or Colour), so work in this tab never recomputes the other. Create one with "Send to … tab" on a node's output.Mask PortalBrings a mask from another tab (e.g. Terrain into Vegetation or Colour), so work in this tab never recomputes the other. Create one with "Send to … tab" on a node's output.