- See also: River tutorial
Ribbon Water is a water shape that uses a B-spline editing system for creating flowing rivers.
The shape of a river is defined by a series of control points along its length. Points can be moved, added, inserted, and deleted with the Select and translate tool, while the width of the river at any given control point and its overall depth can be manipulated with the width/depth/height tool.
Creating Ribbon Water
Editing control points
The two blue circles are control points, while the orange circles represent places where new control points can be added.
To move a control point, simply drag it with the Select and translate tool. Note that it's possible to move control points up and down; the surface of the river need not be flat.
Hold SHIFT while dragging a control point to move the entire river.
To add a new control point, drag one of the orange circles. Circles outside the area of the river will add new points to the ends, while circles between existing control points will insert a new control point between them.
To delete any control point, hover over it with the Select and translate tool and press the DELETE key. There is a minimum of two control points; pressing DELETE when there are only two will delete the entire node.
Note: Be careful with the DELETE key, as using it with any other tool than the Select and translate tool will delete the entire node!
Editing river width and depth
The green arrows at each control point are handles that can be dragged to change the overall depth of the river.
The blue arrows at the edges of the river at each control point can be dragged to change the width at that control point.
Hold SHIFT while dragging a blue arrow to change the width of the entire river.
- Because the curve of the river is a B-spline, you can manipulate it by inserting extra control points.
- Control points that are too close together don't allow for a good smooth curve, and may even "fold" the river surface on top of itself. In some cases, inserting extra control points elsewhere can help tame this effect.
- Don't worry too much about the edges of the river because, if you're building an area correctly, they will be underground anyway. Use the yellow lines along the river edge as a guide when making the river and terrain fit each other.
- With the RIVER water type, the water appears to flow in a particular direction. You can reverse this direction by making the WaveSpeed property negative. You can enhance the effect by adjusting the WaveZoomWidth and WaveZoomDepth properties -- generally it looks best if WaveZoomDepth is larger than WaveZoomWidth.