Wookash Podcast Sebastian Aaltonen on rendering
Apr 25, 2026
Sebastian Aaltonen, graphics engineer and game developer known for virtual texturing, Claybook, and engine-level rendering, dives into rendering tech and tooling. He traces virtual texturing, decal-based terrain, GPU-driven rendering, and distance-field lighting. He recounts indie studio realities, Unity work on DOTS rendering, API design ideas, and AI-assisted creator tooling.
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Building Claybook Pushed Game Logic Onto The GPU
- Sebastian and technical art director Sami Saaren left to build The Second Order and Claybook where Sebastian wrote a GPU physics and distance-field ray tracing stack.
- The game kept ~1GB volumetric data on GPU, ran clay and fluid simulation there, and required painful GPU gameplay debugging.
Try Distance Fields For Faster Better Shadows
- Prefer distance-field ray-traced shadows for soft, fast shadows when feasible; implement sparse/volume representations for performance.
- Sebastian prototyped soft penumbra shadows in one weekend and found them faster and nicer than complex virtual shadow maps.
Two-Person Team Launched Cross-Platform UGC On Consoles
- Claybook shipped cross-platform level sharing and UGC despite console vendors' usual resistance; Sebastian packaged two builds (UGC on/off) for each vendor.
- He recalls submitting different builds per vendor and being surprised that all accepted the UGC-enabled version.