Real-time Destruction FX
March 15, 2025
Week 02: VAT Rigid Body Dynamic in Houdini and UE5
After researching various methods for achieving optimized yet dynamic real-time destruction FX in games, I chose Vertex Animation Textures (VAT) as the best approach. Using Houdini’s RBD solver, I simulated the fracture and movement of concrete debris, then baked the motion into a VAT for efficient playback in Unreal Engine 5. This method allows me to create high-quality destruction effects that look dynamic while keeping performance overhead low—perfect for a simple FPS setup where real-time physics would be too costly.
I. Procedural Fracturing and Simulating
At this stage, I have successfully imported the VATs into UE5. However, I encountered a few issues:
Since the Megascan modular pieces do not have back-face geometry, I used Maya to fill in the gaps, as the RBD simulation requires closed geometry. As a result, the UVs for these areas lack proper information.
The UVs of the inside faces did not transfer successfully, which I plan to troubleshoot during the Houdini export process.
Setting up the texture interaction with Projection Tile is more complex than I expected, as I am still new to Blueprints. This will be the next stage of my project.
III. VAT testing in UE5
By setting up custom fracture areas and active zones, each modular piece generates a unique destruction pattern, adding variety to the scene. I plan to refine the active area controls further and work on separating materials within a single mesh to realistically simulate multi-material destruction, capturing how different materials break and react uniquely in-game.
Additionally, each piece has its own "hit box" generated as a sphere based on its radius. This information will be transferred to UE5 to make the VAT interactive.
