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tomwyn

procedural river systems

Hi all,

 

As always, I've had a plough through the forum & can't quite find a topic covering my discussion, however if one exists I'll gladly move this convo there.

 

I'm starting on a project which involves a lot or aerial/satellite type shots of various landscapes.

 

In terms of terrain generation I'm set, after following a load of CMIVFX tutorials a year or so ago I learnt a load of stuff & am using a VOP SOP to layer various noises to create super nice terrains.

 

However, I'm struggling to decide on the nicest way to generate river systems/outlets in a precedural way, that also sit well within the terrains I'm generating.

 

One idea I've had is to literally set up a sim which flows fluid/particles from the tallest point on my terrain & then use the wet map (or other attrib) to displace the geo. However this seems pretty long-winded and in all honesty I'd like something lighter & faster.

 

Of course I could use some kind of L System, but my main aim is to get the flows to match the terrains (or even base the terrains on the flows if necessary)

 

Can anyone recommend a way to create such a thing using VOPS perhaps? Or does anyone have any experience in creating this kind of stuff in other ways? If so, I'd love to hear!

 

(I've attached some examples images of what I'm trying to achieve)

 

Thanks in advance! :)

post-7190-0-29288300-1390405325_thumb.jp

post-7190-0-46843600-1390405339_thumb.jp

post-7190-0-68233900-1390405351_thumb.jp

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 sim which flows fluid/particles from the tallest point on my terrain & then use the wet map (or other attrib) to displace the geo

I agree this seems pretty long.

 

What comes to my mind...

L-system -> curves -> project (using ray-sop) on the terrain

Generate direction attribute on the curves -> Create particles sim using direction attribute.

 

To have more artistic control, instead of L-system, use an image like your 3rd attachment & trace curves.

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I would suggest using the find shortest path SOP.

If you provide it with a proper grid of your terrain it can do exactly what you need.

I tend to create these grids using a attribwrangle node. Have a look at the findshortest path advanced example for that.

 

For rivers I would use a flowmap to set the cost of the paths, also to make them one directional, since you don't want your rivers to flow uphill.

Next to that to set the start and end points.

And if you need more help send me a PM, I can give you some pointers on how to make it do what you want.

Edited by hyperforce
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Hi shanshore, hyperforce.

 

Thanks for the responses - Definitely food for thought & a much more promising direction than I was thinking of before! I think I'll end up using a mix of both.

 

shanshore, I will definitely need a certain amount of artistic control over certain shots! Curves will be the answer!

 

hyperforce, I think your suggestion of the find shortest path sop is the exactly what I'm trying to achieve in terms of proceduralism & the much wider shots - I just didn't realize this was wrapped into a node in H13 (I'm still on 12.5). I'm going to look into it over the weekend & maybe take up your offer and PM you some questions. Thanks so much!

 

T.

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there was a thread about a very similar question to your´s some years ago ...link ... it should give you some ideas.

however, due to the fact that some things have changed in newer versions of houdini i have attached a file for houdini 13

 

hth.

petz

rivers.hipnc

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