Houdini 20.0 Nodes Geometry nodes

HeightField Erode Thermal geometry node

Calculates the effect of thermal erosion on terrain for a short time.

Since 17.0

Thermal weathering is caused by frozen rocks thawing and breaking, causing features to wear down and smooth out, and material to pile up on the bottom of inclines.

Thermal erosion is more prevalent in regions exposed to a lot of sunlight, because larger day-to-day temperature variations lead to more frequent freezing and thawing.

Thermal erosion is computed by comparing the height field (including debris) against a blurred version of the height field. If the current height is greater than the blurred height, it is eroded proportionally to its sunlight exposure. Thermal erosion is a relaxation process.



Global Erosion Rate

Controls how many meters of the eroding layer or material layer is eroded every iteration.


Controls the softness of the eroding layer or material layer. Higher values would make the terrain easier to erode, causing deeper incisions, more sediment, and more debris being deposited as a result.


Controls whether to use a mask for erodability or not.

Erodability Mask

The name of the erodability mask.

Erosion Rate

Controls the rate at which erosion happens. This is a multiplier on Erodability.

Removal Rate

Proportion of debris from thermal erosion that is deleted. This simulates wind carrying away a certain amount of debris rather than it all accumulating. The default is 0 (no deletion). Negative values correspond to the debris being less dense than the rock, so one unit of eroded rock produces more than one unit of debris.

Cut Angle

Set the angle at which the thermal erosion would stop cutting beyond. A lower angle would make the cuts flatter and allow for more erosion to take place.


Controls whether to use a mask for cut angle or not.

Cut Angle Mask

The name of the cut angle mask.

Random Seed

Random seed to make erosion vary for the same set of variables on the same input.


Grid Bias

Controls how biased the movement of material is. Setting it to positive values would bias the movement in the direction of the principal axes, and when set to negative values, it would bias the movement at angles of 45 degree relative to the principal axes. The default value of zero would mean no bias in any direction.


Controls whether to use a mask for grid bias or not.

Grid Bias Mask

The name of the grid bias mask.


Controls the chunkiness of the material flow. A lower value would make the flow more continuous and a higher value would make the flow more chunky.

Spread Iterations

How many iterations of slumping to simulate. Fast-moving slump layers like water or gravel should use a higher value, while lava or rock should use a lower value.

Max Debris Depth

Stop erosion when the debris layer reaches this depth.

Repose Angle

The maximum slope, measured in degrees from the horizontal, at which the slump layer will remain in place without sliding. To simulate water set this to 0 degrees. For realistic dirt or rock layers, this should be between 30 and 45 degrees.

Stability Mask

The name of the stability mask. This mask can be used to make to debris more stable.

Layer Bindings

Material Layer

Mask field marking on which parts of the heightfield to simulate slumping. Default is debris.

Eroding Layer

Name of the field to use as the eroding layer in the simulation. Default is height.

Below Layers

When eroding a system with more than two layered heightfields, the effective height at a point may be the sum of multiple heightfields. This is a space-separated list of of all the layers below the Eroding Layer (default ).


Name of the field to use as bedrock in the simulation. Default is bedrock.


Adjust Erodability by Strata

Adjusts how erodible rock is by how far it is away from the reference bedrock layer.

Strata Depth

The depth for the strata. The Strata Erodability ramp uses this depth to control how deep it represents. A positive values means the strata represents hardness below the bedrock layer. Negative values mean the strata represents hardness above the bedrock layer.

Clamp at Strata Bounds

Depths outside of the strata range will be clamped to the ends of the ramp. If clamping is off, they will repeat forming a periodic pattern.

Strata Erodability

How erodible rocks are at different strata depths. The left most is at the bedrock reference layer, the right most at the extreme strata depth. Values of 1 are fully erodible, such as loose dirt, and values of 0 prevent erosion, like granite.

Geometry nodes