Simon Trümpler: Sketch #17 WIP

Finished. More pictures in my last post:

Hi guys,

I using this challenge as motivation to learn more houdini. There are very cool tutorials for creating river effects. In case you’re interested:

Here is my current state:

  • A spline defines the river-shape and carves the terrain if necessary, prevents the river from going up again (newsflash, water only flows downward :smiley: )
  • The river geometry + UVs are created

Next steps:

  • Try around with flow maps
  • Create a nice material

Nice! Can’t wait to see more :slight_smile:

Oh, yeah, that is defo comming along. Not very natural, but it might be cool to see human made aquaducts or bridges popping up based on where the river is.

(newsflash, water only flows downward :smiley: )

Then how do you explain this!

Jokes aside, awesome work already!

  • Added “steps” to the river so that it does NOT flow downward constantly but is flat most of the time and then has a little mini-cascade
  • Added detection of those slopes and they are masked via vertex color so that i can later use a different (foamy) texture there


  • converted the whole thing into an houdini digital asset so that it cooks in unreal and i dont have to manually export any geometry

  • since the asset is cooked in unreal, i can change the spline which defines the river directly in unreal and i dont have to do this tweaking in houdini <3

The only problems is, that the cooking takes some seconds so the tweaking of the spline is not “realtimey”.


I do think think I have seen a system yet that’s realtime. Pretty awesome workflow!

What happens if you try putting a rock in the middle of the river?

Yes I saw that realtime-GIF too…no idea how the guy did that :smiley: Anyway: In Houdini you can create a flow-map which lets the water flow around obstacles. I have to check if this can be re-baked automatically every time I change something in Unreal. I did a quick test and the flow-map didn’t work too well but I’ll investigate more later.

1 Like

Finally I got procedural placed particle systems running! I detect “top of cascade”, “bottom of cascade” and “obstacle collision with river” and place different particle systems.

There where MANY problems to get this running and I collected the knowledge here:


Its so weird to see you with multiple YouTube accounts!
This is looking amazing. Keep it up :slight_smile:

Dude this is fucking siiiiiick! I cant wait to see what else you do with this thing. It already has so much potential

@TravisMcCallum yeah i have several channels for different topics. didn’t want to mix them all :smiley:

Update: Flow Maps are working now I think. You can re-bake them directly in Unreal after changing e.g. the spline or the obstacles:


Here’s a first try with a water/foam material. I’m not very happy with hit but time is running out :frowning:


Worked a bit more on the water material (better reflections, more dynamic normal map, higher opacity):

1 Like

Nice effect so far, I guess it’s the better river system game ready I’ve seen for a while !

Just a question : do you want to keep the square particle next to the rocks ? It’s get a pretty good feeling, as indie game, and the polygon on the rocks too. Just wondering if you wanted to go on a realistic way or not, as you already did once for a contest (guess it was the fire, don’t remember :thinking:)

Keep going, I want to see where you are going with this one :smiley:

1 Like

The little squares a meant to be place holders :smiley: I didn’t have the time to do proper particle textures yet but I tested the Houdini System because those guys are procedurally placed. I hope I have enough time but those are next on my to do list. I’m afraid I can’t make it perfect but it was a nice technical exercise! :slight_smile:

1 Like

Improved Water/Foam, added Vertex offset and added first draft of “real” particles.


man, that looks rly cool! good work!

Love the splashes against objects! Getting a great sense of turbulent movement from this.

looks really nice, I like how water material/shader looks like… it’d be nice to see wet/darker terrain where the water is.

yeah… i already darkened the terrain a bit but i wasn’t able to generate a “real” mask. i will try that again. would add a lot! thanks for the hint!