Houdini Decals
For this project I was heavily inspired by the ground slam attack from the game Control. I really liked the visual impact of the attack and how the VFX make the hit feel extremely powerful while still staying visually simple.
My goal was to recreate a similar feeling while exploring a different workflow. Instead of using a simple decal that could be created in programs like Adobe Photoshop or Substance Designer, I wanted the ground crack to come from actual destruction. I simulated a fractured floor in Houdini and then turned the result into textures that could be used as a decal texture.
After creating the textures in Houdini, I brought them into Unreal to make the ground slam effect feel real. I used the height, normal, roughness, and albedo maps to make a decal material for the ground crack.
The heightmap is used with Parallax Occlusion Mapping, which gives the crack extra depth and makes it look like it sits in the ground instead of just on top. This helps the effect feel more 3D and adds realism when the camera moves around.
Reference image from the game Control showing the ground slam attack.
I created the ground crack step by step in Houdini. First I set up a floor and added masks to control where the crack would appear. Then I scattered points to guide the destruction and ran a fracture simulation to break the floor into pieces. I froze the simulation at the moment that looked best for the effect.
Because the setup was procedural, it was easy to expose a few controls to adjust the result. I added two parameters that control the number of scattered points and the random seed. This made it easy to quickly generate different variations of the crack by simply adjusting two sliders.
After that I used Houdini’s Copernicus tools to turn the simulated geometry into texture maps. Copernicus converts 3D mesh detail into a heightmap, normal map, roughness map, and albedo map. Using this workflow let me create a ground crack that feels real and has depth while still being efficient for real-time use.
The decal is combined with a Niagara system that adds sparks, flying smoke, dust, and colliding rocks. I also added a small refraction sphere over the impact and a camera shake to enhance the feeling of power. The video to the left showcases all the different layers of the VFX
Below is a video showcasing the ground-slam attack from 4 different angels in a zoomed out view
This project taught me how to use Houdini for the first time to create procedural destruction. I learned how to fracture geometry, control simulations, and convert the resulting meshes into height, normal, roughness, and albedo maps using Copernicus for Unreal.
I also learned how to set up procedural controls in houdini, like scatter points and random seeds, to quickly generate variations of the ground crack. Testing the textures in Unreal with Parallax Occlusion Mapping and Niagara effects showed me how to translate a Houdini simulation into a polished, efficient real-time VFX while preserving depth, detail, and visual believability.
...I would spend more effort on the refraction shader to improve its visuals. Instead of using a sphere, I would try using a sprite to make the effect less in your face when the attack is used.
I would also expand the Houdini destruction tool to handle more types of destruction. Right now it’s set up for a single ground slam, but adding variations like a bullet impact or a fist strike would make the tool more flexible and usable for different situations.
I am part of The Game Assembly’s internship program. As per the agreement between the Games Industry and The Game Assembly, neither student nor company may be in contact with one another regarding internships before April 15th. Any internship offers can be made on April 27th, at the earliest.
