3.0.riverpreview1 Released

[Stephen]

(Image is from the "Worked Example from Tutorial 3" example world file)

River Tool

As befits a Development release, there are a number of known issues currently present; they will be mentioned in a seperate post. You will likely encounter some odd behavior or bugs; please report them as you find them!


The river device is a major expansion of World Machine's path tool, providing a great deal of power and flexibility in creating "hero" rivers; that is, major rivers that should be under artist control, as opposed to those created by an automatic simulation-type process.

I highly recommend reading this post on our Development Blog, which should be educational:

Learn about Rivers

The blog post above defines a few terms that you'll hear thrown about frequently talking about the river tool, including things like Thalweg, Bankfull Width, Meanders, and more.

A number of tutorial worlds have been included in the "New Examples for River" folder, leading you from the simple to the complex. Hopefully additional guidance will be available soon to assist you.

The River Tool was created in collaboration with Dr Pasternack and Brown and their work into synthetic river valleys. It  uses a geomorphic covariance structure (GCS) to describe the variations in the river channel and valley. Realistic (or not..) river features can be easily created, especially including variations in the river channel itself (depth and cross section), that have usually been completely ignored by computer graphic artists to date!




If you have questions, please post them here in the forums; many other people are likely to have the same questions, and having the answers in one spot is immensely useful.

Joining the river tool are the following immediately useful additional new features:

Other Immediately Useful New Features

- Erosion Improvements
-- Active Masking Input allows you to have rivers and other masks carry away sediment that hits them.
-- Hardness Input allows you to vary the intensity of erosion across a terrain

- Better Curves
-- Curve device and Layout falloff curve now can use spline curves and share presets between them.
-- Curves are now a seperate datatype, and include sinusoidal, cnoidal, and perlin curve generators. More to come.

- Scene View device allows you to superimpose a water surface on the terrain.
- Advanced Perlin gains ability to specify the resulting elevation range in the device itself more accurately
- Minor view improvements : WASD keys can be used in the 3D view to navigate; View responsiveness and control now works better for render extents much smaller and larger than the standard 8km block.
- Device Versioning : To help with backward compatibility, devices can now have "versions"; when a new version of a device is available, you can update the device to the new functionality or simply keep using the old version for compatibility if needed.

[Chariots]

I'm not sure if this is an issue on my end, or already known. I get this whenever I switch to layout view. https://www.dropbox.com/s/lmkz4zakm40z08h/Screenshot%202015-07-07%2012.29.41.png?dl=0

Other than this, haven't had any issues tinkering with it for a few hours.

Edit: Lowering layout resolution to 262k or less fixes it.

[goblox]

Wow - I'm pretty excited to work on this; the samples look great.

I get the impression that the magic can only be performed on a user defined spline?  if so, will we see a more hands-off implementation with a handful of parameters to tweak in terms of the likelihood of a flow being generated (possibly relying on a base elevation map - considering most rivers I float down run downhill ... gradually, like what? 1':50' or 1':100'?- while World-machine, seems to assume water always occurs at a particular elevation)? I appreciate that I'm over simplifying this task. I would assume if nothing else I could procedural generate my own splines? In general it seems like as the scale of the terrain being generated increases, so does the need for automated water flows. ...even if I define a hero river, it sure would be nice if tributaries could be automagically generated.

[Stephen]

Chariots:

I believe you've run into the odd blanking issue described in the Known Issues here:

http://forum.world-machine.com/index.php?topic=2367.0

This is a regression that snuck in when seamfixing is enabled. I will track it down for the next update.

goblox:

Yes -- right now the focus is "hero rivers" only. I foresee several stages as we move from individual hero rivers to river systems. As you move to more automated river systems, the main issue at play is this:

In a very real way, terrain is shaped and defined by rivers far more than the other way around! The interaction between the two is intertwined; this makes "water droplet" style river creation go astray as the procedural terrain is not properly drained. At a minimum, you would need to combine user-placed hero rivers that define the main drainage basins in your world before adding tributaries procedurally. There is also some interesting idea-space whereby you place your rivers, and an algorithm builds terrain around it to match.... The new active masking erosion mode combined with the river tool is almost starting to approach this idea.

There's an almost endless direction of approaches you could take with this. Hero rivers made the most sense as a place to start as they form the building block of all other approaches, as well as being the most useful in isolation.

[sfriedberg]

In a very real way, terrain is shaped and defined by rivers far more than the other way around!

This is certainly true for real geology.  There are lots and lots of examples where rivers have eroded terrain faster than the geological processes raising the terrain into mountains.

The Delaware Water Gap is a classic example.  There's a hole in the Appalachian Mountains where a pre-existing river cut across the region as the mountains were created.  The Grand Canyon is another example, but of a very different shape.  The Colorado River did not sink 7000 feet.  The plateau around it rose while the river more-or-less stayed on the same level.

[goblox]

the procedural terrain is not properly drained ... define the main drainage basins

It seems like defining a sea-level or scope (Then simulating some percentage beyond the scope to minimize error) would be the answer to drainage but there's no shortage of lack-luster water droplet simulations out there to prove that it's not easy to make a convincing model. ...and of course without all of the other erosion components you've implemented, even a fantastic hydraulic action sim would fall apart where other activities dominate. ...and all the while we are relying on noise generators to play the part of so much already. Hopefully I'll get my hands on what you have soon.

Thanks

[Naima]

I have some questions.

Those rivers:

Do have a slope ? I mean they go from a higher height toward sea level or lake level? Or are just like roads drawed?

Do the rivers get automatically created following flow charts and drainage maps sediment?or need always the human hand input?

Can we just give a starting point and a end point and let the engine do the work of finding or carving the right path?

Do they carry sediments? Can we realize also dried rivers?

[Stephen]

Hi Naima,

1) Yes -- the gradient of the river is currently specified numerically. In the next release, the ability to set the endpoint elevations from the terrain will be added.

2&3) The river path is specified manually -- see the conversation above about the perils of using flow maps on artificial landscapes. This might make more sense for tributaries and such

4) Sort of -- the new active masking of the erosion device can use the river channel to transport away sediment from the landscape as water runs into the river. The actual sediment carrying capacity, however, is not modelled.

5) Dried rivers -- sure, a dry riverbed is simply a river, with no water...