How To Use

Placing and Extending the River

Start by placing the BP_FlowmapRiverSystem Actor into the world.

To extend the river out, select the end spline point (1) hold ALT on your keyboard and LEFT CLICK with your mouse to drag out the point, this will create a new spline point for the river.

Branching the River

For this tutorial we have a basic river shape created with the Landscape Editor Mode and built with a single BP_FlowmapRiverSystem.

Once the first river is placed, navigate to the Details Panel of the Actor and press the Update River button.

This will fill the River Splits array with all of the river's Spline Points.

Branching Into

Within the River Splits array, find the closest Spline Point at which you want to have your river branch.

In this example, we're branching into Spline Point (1) so we will select the option Right End, which will split the river at the end of Spline Mesh (1).

Next we place down another BP_FlowmapRiverSystem. this will be used as the river branching into the previous one.

Within the Details Panel of the newly placed river, navigate to the AttachEnd input. Select the original river for this input, and then under the AttachEndIndex set this to the visually split river Spline Number.

Press the Update River button on the newly placed river and it should snap into location.

We now want to make sure the new river has the right river split to reduce mesh overlap. In this example, Left End is the correct choice for Index [2].

Branching Out

Branching out of a river is similar to branching into. In this example we branch out of Index [3] on the main river using the Left Start option.

From there we place down another BP_FlowmapRiverSystem into the scene. This river will be used as the river branching out the main one.

We then set the AttachBeginning and AttachBeginningIndex to the main river and Spline Point (3).

Next we press the Update River button and set the river split Index [0] to the Right Start option.

You should now have a branched river!

Vertex Painting

This system uses Epic's built-in Mesh Paint Mode for Vertex Painting. We currently have no up-to-date tutorial on using this feature, but Epic's documentation can be found here: https://dev.epicgames.com/documentation/en-us/unreal-engine/mesh-paint-mode-in-unreal-engine.