The VFX tech behind Saros: how NGP became Graphite

Housemarque has detailed Graphite, the unified VFX framework built for Saros that replaces NGP — Next-Gen Particles — the particle engine the studio had been growing since a Resogun prototype in 2013. Graphite brings GPU simulation, rendering, tooling, and DCC integration under one architecture built directly for PlayStation hardware.

NGP ran through every Housemarque game up to Returnal, but twelve years of incremental, game-specific decisions left it fragmented. Joining PlayStation Studios pushed the team to step back and rebuild rather than extend. NGP didn't get scrapped — it evolved into a component of Graphite. The most visible result in Saros is the volumetric fog system, explained in detail by Graphics Architect Sharman Jagadeesan and Senior Graphics Programmer Konsta Toivanen. The team built two complementary solutions: low frequency fog for ambient atmosphere across Carcosa, and high frequency fog for the special story rooms. Starting from Unreal Engine's froxel fog — a frustum-aligned voxel grid — they rebuilt significant parts of it. Unreal's default hysteresis coefficient sits at 90%, which keeps the image stable but makes fog sluggish on fast-moving cameras and lights; Housemarque dropped it to 50% and used blue noise jitter plus depth clamping to keep aliasing in check. To handle everything from thin ambient mist to dense ground fog, the system uses a dual Henyey-Greenstein phase function to model how light scatters forward and backward depending on viewing angle, a coloured absorption coefficient for a far wider colour range than monochromatic approaches allow, and a self-shadowing system that aggregates incoming light sources into a dominant shadowing direction and ray-marches toward it. VFX Architect Risto Jankkila covers the Houdini side of Graphite, including a full breakdown of the player spawn sequence.

Returnal already had reactive volumetric fog, but it ran at too low a frequency and heavy temporal filtering prevented fine detail from showing through. Saros is a direct answer to those limitations. As a platform rather than a per-game tool, Graphite means Housemarque can carry these systems forward rather than rebuilding from scratch each time.