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Simon Trümpler
VFX Artist at Wild Sheep Studio
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Liquid Erosion

I'm using Blenders "Dynamic Paint Canvas" to capture a liquid getting splashed on a surface over time resulting in an image sequence of "wet maps". To combine them into one image (adding then on top of eachother) I wrote a Python Script which generates an "erosion map". With a simple SmoothStep-Material, this map can be used to fade the liquid in/out nicely.

My python script: https://cloud.simont.de/index.php/s/c2w2rYnN6H2pQ6q
Base-Idea described in this Sea of Thieves Talk: https://youtu.be/KxnFr5ugAHs?t=658
I was inspired by a FLIP Fluid Tutorial: https://youtu.be/GYGNoTmZSN0
How to setup an erosion material: https://realtimevfx.com/t/what-is-your-alpha-opacity-mask-clip-erode-animation-workflow-like/7705/15?u=simonschreibt
Quickly render Normal Map from Blender: https://youtu.be/h24akA8K-40

A liquid which appears over time based on an erosion map. The wetness on the ground is a 2nd erosion map with Blenders Canvas-"Spread" enabled. The base-technique was discussed in this great Sea of Thieves Talk: https://youtu.be/KxnFr5ugAHs?t=658

A liquid which appears over time based on an erosion map. The wetness on the ground is a 2nd erosion map with Blenders Canvas-"Spread" enabled.
The base-technique was discussed in this great Sea of Thieves Talk: https://youtu.be/KxnFr5ugAHs?t=658

I used a Blender FLIP Plugin for the liquid and Blenders "Dynamic Paint Canvas" which "tracks" everything it touches - in this case the liquid. The result is an image-sequence. I baked a 2nd image-sequence where the wetness is spreading.

I used a Blender FLIP Plugin for the liquid and Blenders "Dynamic Paint Canvas" which "tracks" everything it touches - in this case the liquid. The result is an image-sequence. I baked a 2nd image-sequence where the wetness is spreading.

I wrote a Python-Script which grabs all the images and stacks them on top of eachother into ONE image which is now my erosion map. With a simple shader those grayscale values can be faded on/out nicely.

I wrote a Python-Script which grabs all the images and stacks them on top of eachother into ONE image which is now my erosion map. With a simple shader those grayscale values can be faded on/out nicely.

Here you can see the textures and some "gotchas". The normal map was created via Photoshop-Filter from the last rendered Blender-Frame.

Here you can see the textures and some "gotchas". The normal map was created via Photoshop-Filter from the last rendered Blender-Frame.

The pretty simple material. Of course, values like "base color" are different in my Material Instance for the final look.

The pretty simple material. Of course, values like "base color" are different in my Material Instance for the final look.

Update: Bruno had a great idea! Here is the result, you can find a detailed description below.

Update: Bruno had a great idea! Here is the result, you can find a detailed description below.

Brunos cool idea: Instead of the complex canvas/python-experiement, you can use a camera capturing the zDepth liquid-geometry from below. I used a B/W-Gradient to simulate the depth in my test and it worked out really nice.

Brunos cool idea: Instead of the complex canvas/python-experiement, you can use a camera capturing the zDepth liquid-geometry from below. I used a B/W-Gradient to simulate the depth in my test and it worked out really nice.

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