How to Use Essential River Tool Functions

Overview

This tutorial shows you how to build a river with the Sandbox2 editor. After you learned how to modify dimensions of the river we go into detail about assigning the correct material so it looks realistic. 

Also, if you want, have a look at the particle tutorial to learn how to add particle effects to your level, with particles you can enhance your river, by placing foam particle entities to make the effect of flowing water even more real. 

Preparing the terrain for the river

 

Placing a river entity

Enter the objects section of the RollupBar click Misc and then *River. Now you can draw the river in the perspective viewport. 

First click on the terrain will create the first point. 

Second click will create the middle point of the river. 

Double-clicking a third time will complete the river. 

Do not worry about parts of the river disappearing in the terrain, we will adjust that later. 

Later you can adjust the shape, add more points/remove points by clicking the Edit button in the Shape Editing section. 

To build the river bed set the width of the river to 20 and press the Align Height Map button. 

 

This adjusts the height of the terrain to the river shape and height – a very handy tool to shape terrain for other purposes, too, and can also be done with the Road tool. 

Forming the bed of the river

 

Now set the width of the river to 10. With the river shape selected move the entire shape a little bit down by clicking on the yellow Y axis helper object line, holding the left mouse button and moving the mouse towards you. 

Next, press again the Align Height Map button again. 

The river will always be a flat plane that, by default, hovers in the air. Rotate it to make it flow downhill. 

Also, to make the river look like it is flowing along the terrain, it’s a nice idea to adjust the terrain beside the river. See the terrain editing tutorial on how to do this. 

To make a 10 meter wide river blend with the terrain, simply set its width to 20 or 40 this will make the river wide enough so no gaps with the surrounding terrain will be visible. 

Making the river look nice

Assigning a material

Assign a material to the river (for example Materials/Ocean/river_village) using the material editor 

Select the material and assign it with the top left button in the material editor. 

Other river parameters

In the river parameters you can adjust how the material tiles. Also, you may notice the speed parameter of the river can be adjusted here. This is only the speed at which physicalized objects will float down the river, and doesn’t affect the look of the river itself. 

Example river perameters

Below is a nice example setup of parameters you can use. You can just copy them into the River Params box. 

Width = 30 

BorderWidth = 8 

StepSize = 6 

ViewDistRatio = 100 

TileLength = 4 

Depth = 10 

Speed = 0.5 

FogDensity = 0.5 

FogColor = 61,86,91 

FogColorMultiplier = 0.1 

UScale = 0.05 

VScale = 0.2 

Result

 

Once you have everything setup the river should flow gently. To enhance the look of the river obviously the ground material needs to be painted with an appropriate texture and vegetation added. 

 

Some things to experiment with: 

To make the river flow down from a mountain to the ocean, the river shape needs to be rotated (only use small Z values like 0.5 or 1).