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Overview
TABLE OF CONTENTS
Generation Methods
The river system gives you several different ways, which are presented below, to build your network. In general, it is designed to allow you to create a complete procedural river network as quickly and easily as possible, giving you a starting point for then creating the perfect river layout for your terrain with precise control over every aspect of the result.
Ideally you will want to start with the Auto Generate/Build from Spring approach as both of these will create brand new river networks.
The Generate Stream functionality, on the other hand, can be very useful when modifying an existing network, as it works well within your current river network.
Auto Generate
Automatic generation is the easiest way to get a river network for your terrain. To do this, press the Rebuild Rivers button in the generator settings. World Creator will then automatically analyze your terrain, calculate flow paths, place and connect springs and river nodes and assign different river types according to the hydrological properties sampled at the determined locations.
To then further refine your river network, press the Edit button at the bottom of the panel to gain full control over every aspect of the generated system.
Bear in mind that this mode will create a completely new system, so any changes you've made to the river network will be overwritten.
Auto generated river network
Generate from springs
This approach gives you full control over where the rivers start as you only have to place the springs and let World Creator handle the river generation downstream from there. To add a spring, simply press Shift & LMB in the Edit mode.
You now have two options:
- Build From Springs
This works in a similar way to Auto Generate and will create a completely new river network based on your springs, i.e. everything other than the springs in the layer will be overwritten.
placed springs
built graph from springs
- Generate Stream
This will only create a river from the currently selected spring. It works within an existing river network, so all other rivers will be left untouched and the newly created river will flow into an existing river if it encounters one.
auto generated terrain with an additional spring
generated spring connecting to an existing river
Build from scratch
Besides the procedural generators World Creator offers you also have the option to fully construct your own graph. To add a new node enter the Edit mode and press Shift + Lmb. With Shift + Drag from the new node you can now place a new node connected to the original which allows you to build up your network.
Additionally you can also fuse nodes together by using Ctrl + Drag and dropping it on another node.
custom built river graph
General Concepts
World Creators River Layer offers a complex river network system with several core design concepts as its foundation. Understanding these is highly recommended to unlock the system's full potential.
River Types
Each River Node can be one of the river types listed below. The automatic determination of River Types is based on the expected throughput of water and the slope of the terrain at a node's location.
The River Types are inspired by the different Rosgen Types used in the geological stream classification and affect:
- Course of the river - straighter and faster flowing or more meandering
- Cross-section - V-shaped entrenched or smoother, wider profile
- Stream Count - Braided or Multi-Threaded River Types are made up of several individual channels
- Rendering Multipliers - Each River Type internally influences the different rendering multipliers to create, for example a flood-prone area or wider valleys around the stream.
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Flow
Flow describes the volume of water at each River Node and affects the width, sinuosity and depth of the river. The flow value is calculated by adding up all incoming flows of a node's parent nodes.
There are several ways to control the flow at a particular node:
- Increase the flow of the base spring or any node above the wanted node.
- Adjust the flow multiplier at the given node to increase its flow relative to the inflow.
- Activate Set Flow and manually override the current flow value of the node. Note that this will break the link between the flow of upstream nodes and this node. Nodes further downstream will be affected by the new flow value.
flow modification (multiplier and absolute set further downstream)
Valleys
Valleys are structured around the stream, providing a base for the stream to flow into and controlling the blend between the stream itself and the terrain. By default, they work on the lower levels of the level-step system to blend in with the terrain.
The valley is divided into two parts:
- The floodplain that surrounds the possibly meandering stream and provides a base for the river to flow through.
- The valley, which lies outside the floodplain and blends into the original terrain, with additional options for additional noise and control over the shape of the transition.
valley carving through a hill
Controls
- Select Node
Press Left Mouse
- Adjust upstream Nodes
Hold Shift
- Move a Node
Press Left Mouse and Drag (can be combined with Shift to affect all upstream nodes).
- Rotate a Node
Press R, Left Mouse and Drag (can be combined with Shift to affect all upstream nodes).
- Adjust Node height
Press Alt, Left Mosue and Drag (can be combined with Shift to affect all upstream nodes).
- Remove a Node
Press Ctrl and Right Mouse (can be combined with Shift to affect all upstream nodes).
- Add a Spring
Press Shift and Left Mouse
- Add connected Node
Press Shift, Left Mouse and Drag
- Merge into another Node
Press Ctrl, Left Mouse and Drag
Layer Parameters
Generator Settings
- Use Global Sea Level
Links the internal sea level of the layer to the global sea level used for ocean rendering.
- Sea Level
The height at which the generator ends new rivers.
- Branching
Increases the number of crossings and branches the generated river network will have.
- Max Lake Depth
The river ends when the generator reaches a point where no lower neighbouring cells exist, creating a local depression that would form a lake with the minimum given height.
- Slope Multiplier
Multiplies the slope values at each node, which affect the automatically determined river types at each node. For a standard terrain, a value of 1 should work best. Adjust this if you are going for more extreme, steeper terrains.
- Min Flow
The minimum flow each node has. Increase this to get stronger rivers overall. This also changes the automatically determined river types.
- River Type Smoothing
Assimilates river types between intersections to create a more unified and coherent river.
Shape Parameters
- Seed
The river layers global seed.
River Shape
These settings affect all streams of the river network and are mainly global multipliers for the parameters found in each node.
- Depth
Alters the depth of all streams.
- Width
Changes the width of all streams.
- Curve Amplitude
Allows you to increase/decrease the strength of the curve effect applied to the stream, which can create more/less widely meandering rivers.
- Curve Repetition
The scaling of the curve function that runs along the river streams.
- Levels
The strength of the stream carving on each level step.
Valley Shape
These settings affect the valleys surrounding the streams, ensuring a smooth integration of the streams into the terrain. They are split into a floodplain area where the river stream can meander and a blending area that slowly fades into the terrain.
- Width
Multiplier for the width of all valleys.
- Depth
Shifts all valleys downwards.
- Wall Shape
The steepness of the blending between floodplains and terrain.
- Breakup
Adds additional noise into the blending region between floodplains and regular terrain.
- Floodplain
Controls the width of the floodplain area.
- Floodplain Flatness
Controls the flatness of the floodplain.
- Levels
The strength of the valleys on each level step.
Spline Export
- Export Spline
Exports all streams as a spline in a .dae file.
Editing Parameters
These parameters become available once you press Edit at the bottom of the River Layer panel, allowing you to adjust your rivers in more detail on a node-by-node basis.
General Settings
- Clear Springs
Removes all nodes (springs & regular nodes) from the current river network.
- Build From Springs
Recomputes the river network from all given springs in the current river layer and builds their downstream stream network.
Selected Node
- Seed
The seed of the current river node.
- Set Flow (only available on non-spring nodes)
Toggles between the Flow Multiplier value (relative to the upstream parent node) and the Flow value (absolute flow value).
- Flow Multiplier (only available on non-spring nodes)
Takes the parent node's flow value and multiplies it by this modifier to create the current node's flow value.
- Flow
The absolute flow value of this node.
- Custom River Type
Lets you change the current node's automatically determined river type.
- River Width
Multiplier for the width of the riverbed.
- River Depth
Multiplier for the depth of the riverbed.
- Floodplain
Multiplier for the width of the current node's floodplain.
- Valley Width
Multiplier for the width of the surrounding valley.
- Walls
Multiplier for the wall steepness of the valley blending.
- Channel Count (only available for River Type Braided and Multi-Threaded)
Number of stream channels.
- Curve Amplitude
Increases/Decreases the curve amplitude for this node.
- Curve Repetition
Increases/Decreases the curve repetition for this node.