Behind the Scenes: Adapting Waterfall

INTRODUCTION

Hi, I’m Simon, living in Munich, Germany.

I started into the whole world of 3D at the age of 16; it was still the Blender 2.49 area or earlier, I don’t remember exactly. I tried to make films with my friends and needed spaceships flying through the scene. I thought it could not be too hard to make but as I discovered it actually is, I got on a never-ending journey into Blender and still am.

In 2016, I got lucky enough to get employed as a professional full-time 3D artist, and even today, I sometimes cannot believe that I managed to make my hobby into my profession.

INSPIRATION

I love fluid simulations! Ever since Flip Fluids got released, I've been playing with it and dreaming of achieving something like all the incredible examples from Houdini I kept seeing. Now, of course, Blender and Flip Fluids don't play on the same level as Houdini, but it's still awesome what's possible to do with it.

I find it very satisfying to see the CG water finding its way through the environment I created and the possibility to influence and guide it. And in this specific case, I wanted to have it run down a cliff and see it adapt to new obstacles I would throw in its way.

PROCESS

Environment

The entire scene was created in Blender with the help of the Flip Fluids Addon, which I use and love since it was first released a few years ago.

The Flip Fluids addon can be purchased from the Blender Market or from the official website.

The environment I assembled out of a pack of scanned cliffs that I bought from Blender Market a while ago. Since it's not a good idea to use very high geometry as obstacles for Flip Fluids, I copied the cliff layer and used the Decimate Modifier to make a collection with low poly cliffs that the water would use as a collider.

Waterfall

I ran multiple simulations and played with the World scale and Whitewater settings to achieve the look that I had in mind. Important for me was the generation of enough Whitewater once the water gets over the cliff or collides with the obstacles.

To achieve this, I used higher numbers for the Wavecrest Emission Rate and the Turbulence Emission Rate, as well as lowering the Max Energy that is needed to create Whitewater. Also allowing a very high amount of maximum particles that can get generated helped me with the look. And of course, it's also important to use Motion Blur for the waterfall look (make sure to activate it before baking the simulation).

The addon has a feature that allows it to influence the color of the fluid surface according to its speed, which could be used to color the water white once it was over the cliff and in free fall, helping with the look of a waterfall.

Rendering & Simulation

As hardware, I use an AMD Ryzen 7 and the Nvidia GeForce GTX 1070. The number one question that I always receive about my simulations is the one about the hardware and the estimation that a scene like this is only possible with the latest and best hardware available. But it's actually not true; even older hardware can do it; you just need to be more patient and use your time better. I noticed that it's not a problem to start the simulation and let it run in the background while you're working on other parts of the scene or other projects. And after a while, you can come back and see the result.

Also, Flip Fluids offers a nice feature to always preview the latest simulated frame to give you an idea if your simulation is going in the desired direction, so you don't have to wait for the whole simulation to finish but can make changes early on and resume or restart the simulation.