support@demenzunmedia.com
BC Canada

Erosion Menu

The erosion menu contains a group of modifiers that perform erosion algorithm changes to the terrain heightmap.

Applies an erosion algorithm over the heightmap to simulate real-world erosion effects.
Erosion algorithms use “constant size space” regions on the heightmap to perform the erosion function, therefore they always treat the heightmap as a size-based entity and not as a detail-based entity (eg 2048 is twice the distance size as 1024, not twice the detail).

Some of the erosion algorithms are extremely computation and memory intensive, and can therefore take many hours to complete on large heightmaps.
It is always best to try a less intense erosion setting such as less Time first to determine whether it produces the desired effects.

The erosion algorithms are not a fast immediate real-time operation, so the Preview button must be used to generate an erosion preview, followed by a wait until the erosion function is complete, as indicated on the preview progressbar.

Different erosion types produce different erosion results.  Each erosion type is suited for specific visual looks and different terrain layouts.

Masks are created during the erosion process, which can be saved as files and used for texture weightmaps, splatmap textures, or image editing masks.

Notes:
This function does not preserve the original altitude data.
The Hydraulic Erosion function requires 2 masks and 4 floating-point temporary arrays.
The Slope Erosion function requires 1 mask and 5 floating point temporary arrays.
The Thermal Erosion function requires 1 mask and 2 floating point temporary arrays.


Hydraulic

Hydraulic erosion simulates rainfall with soil erosion and movement from higher altitudes to lower altitudes.
This algorithm treats all soil of all elevations as the same rigidity, it does not have a solid rock under loose soil system.
Therefore, if the erosion algorithm is ran for long enough it will effectively flatten out the terrain.

Preview toolbar: A set of toolbar buttons for preview options.
Preview: Provides a thumbnail preview of the altitude settings.
Preview statusbar: Preview information status.
Altitude bar: Heightmap altitude display bar.

Sediment: The amount of sediment that the water can carry.
Deposition: The sediment deposit rate.
Soil hardness: The rate at which soil converts to sediment.
Rain delta: The amount of time between each rainfall.
Rain amount: The amount of rain that falls for each time step.
Rain type: The rainfall type:
– Equal coverage = the rain amount is equal over the entire map.
– Adiabatic weighted = more rainfall at higher altitudes (natural).
– Inverse Adiabatic weighted = more rainfall at lower altitudes (unnatural).
Evaporation: The rate of rain water evaporation at each time step.
Smoothing: The amount of smoothing applied after the erosion.
Time: The number of erosion passes to simulate the amount of time passed.

Deposit mask: The Deposit mask file name.
Water mask: The Water mask file name.
Smooth masks: Apply a gaussian blur to smooth the mask edges.
Save the masks to disk: Save the masks to disk.
Format: The mask file format to save as.
Folder: The file folder where the masks are saved.

OK: Apply the settings.
Cancel: Cancel the dialog.
Preview: Execute the erosion preview.
Build progressbar: Display the build progress for long tasks.
Copy: Copy the dialog properties to the system clipboard.
Paste: Paste the dialog properties from the system clipboard.
Reset: Reset the dialog controls to their initial values.
Default: Set the dialog controls to their default values.


Rain

Rain erosion simulates erosion over the heightmap terrain by generating a random XZ coordinate on the heightmap, and dropping a raindrop “brush”, that then flows along the layout of the terrain, carving the erosion channel and moving the soil sediment downward.

Preview toolbar: A set of toolbar buttons for preview options.
Preview: Provides a thumbnail preview of the altitude settings.
Preview statusbar: Preview information status.
Altitude bar: Heightmap altitude display bar.

Rain amount: The number of raindrops to randomly drop on the terrain.  Includes Auto buttons to quickly choose the typical number of raindrops based on the heightmap area, including 1/2 and 1/4 Auto amounts.
Deposition rate: The amount of soil that is deposited in basins during water flow.
Deposition smooth: The amount of smoothing that occurs on deposited soil basins.
Erosion type: The type of erosion brush size.
– Thin: 2×2 bilinear brush
– Medium: 5×5 bilinear brush
– Thick: 11×11 bilinear brush
– Extra thick: 21×21 bilinear brush
– Random: randomly choose a brush size for each raindrop.
Erosion rate: The soil erosion rate of the raindrop.
Soil carry capacity: The soil carrying capacity of the raindrop water.
Evaporation rate: How quickly the raindrop water evaporates.
Direction inertia: The amount of inertia for changes in water flow direction.
Minimum slope: The minimum heightmap slope before erosion stops.
Gravity: The amount of gravity (velocity) applied to the raindrops.
Subterrain depth: The amount of altitude that an erosion raindrop can dip below the lowest heightmap altitude.
Post smoothing: The smoothing size and strength applied to the heightmap after the erosion raindrops are completed

Erosion mask: The Erosion mask file name.
Sediment mask: The Sediment mask file name.
Smooth masks: Apply a gaussian blur to smooth the mask edges.
Save the masks to disk: Save the masks to disk.
Format: The mask file format to save as.
Folder: The file folder where the masks are saved.

OK: Apply the settings.
Cancel: Cancel the dialog.
Preview: Execute the erosion preview.
Build progressbar: Display the build progress for long tasks.
Copy: Copy the dialog properties to the system clipboard.
Paste: Paste the dialog properties from the system clipboard.
Reset: Reset the dialog controls to their initial values.
Default: Set the dialog controls to their default values.


Slope

Slope erosion simulates water flowing down the slope of each patch of the terrain, carving a fluvial path downhill.
This is a fast and simple erosion algorithm that only gives limited quality results for some heightmap cases.

Preview toolbar: A set of toolbar buttons for preview options.
Preview: Provides a thumbnail preview of the altitude settings.
Preview statusbar: Preview information status.
Altitude bar: Heightmap altitude display bar.

Erosion rate: The rate of cellular erosion for each time step.
Diffusion rate: The rate of cellular diffusion for each time step.
Rain amount: The amount of rain that falls for each time step.
Rain type: The rainfall type:
– Equal coverage = the rain amount is equal over the entire map.
– Adiabatic weighted = more rainfall at higher altitudes (natural).
– Inverse Adiabatic weighted = more rainfall at lower altitudes (unnatural).
Evaporation: The rate of rain water evaporation for each time step.
Slope bias: Erosion slope bias, how the water follows the slope of the terrain.
Smoothing: The amount of smoothing applied after the erosion.
Time: The number of erosion passes to simulate the amount of time passed.

Flow mask: The Flow mask file name.
Smooth masks: Apply a gaussian blur to smooth the mask edges.
Save the masks to disk: Save the masks to disk.
Format: The mask file format to save as.
Folder: The file folder where the masks are saved.

OK: Apply the settings.
Cancel: Cancel the dialog.
Preview: Execute the erosion preview.
Build progressbar: Display the build progress for long tasks.
Copy: Copy the dialog properties to the system clipboard.
Paste: Paste the dialog properties from the system clipboard.
Reset: Reset the dialog controls to their initial values.
Default: Set the dialog controls to their default values.


Thermal

Thermal erosion simulates the breaking up of soil due to thermal expansion and contracting.
This erosion algorithm typically creates small ridges and terraces on the heightmap terrain

Preview toolbar: A set of toolbar buttons for preview options.
Preview: Provides a thumbnail preview of the altitude settings.
Preview statusbar: Preview information status.
Altitude bar: Heightmap altitude display bar.

Talus min: The minimum altitude difference before erosion occurs.
Talus max: The maximum altitude difference when erosion occurs.
Strength: The erosion strength
Weighting: The erosion deposit weighting type:
– Difference weighted.
– Maximum average weighted.
Time: The number of erosion passes to simulate the amount of time passed.

Deposit mask: The Deposit mask file name.
Smooth masks: Apply a gaussian blur to smooth the mask edges.
Save the masks to disk: Save the masks to disk.
Format: The mask file format to save as.
Folder: The file folder where the masks are saved.

OK: Apply the settings.
Cancel: Cancel the dialog.
Preview: Execute the erosion preview.
Build progressbar: Display the build progress for long tasks.
Copy: Copy the dialog properties to the system clipboard.
Paste: Paste the dialog properties from the system clipboard.
Reset: Reset the dialog controls to their initial values.
Default: Set the dialog controls to their default values.