Yharnam is one of the most-modelled cities in games. Lance McDonald and Illusory Wall have spent years reverse-engineering FromSoftware's rendering pipeline. Here is what we learnt.
The engine · KILN
Bloodborne runs on the same FromSoftware proprietary engine as Dark Souls 1, the team internally calls it KILN. It is a deferred renderer with a custom shadow system built around grid-aligned light occluders — useful for medieval architecture, miraculous for Yharnam's sprawling Victorian skyline.
The 30 fps cap and why it stuck
Lance McDonald famously patched a 60 fps build that runs natively on PS4 Pro. The cap was never a hardware limit — FromSoftware locked it because their physics step is tied to frame timing. Unlock it and ladder climbs go double-speed, AI windups misfire.
Geometry batching · the secret of dense Yharnam
KILN groups static meshes into batches of about 4,000 triangles each — a deliberate balance between draw-call overhead and culling efficiency. Yharnam Central has roughly 12,000 of these batches in memory; the bench-top PS4 Pro renders about 800 per frame.
The fog wall trick
The mist-walls between bosses are not just visual occluders — they are a streaming boundary. Crossing one triggers a full GPU pipeline flush so the boss arena geometry can be brought in. On standard PS4 the flush takes about 1.4 seconds; on PS4 Pro about 0.9. Hence the inevitable second-pause as the fog parts.
Why the Chalice Dungeons feel different
The procedural Chalice geometry uses a simpler shader path — single light source per room, no parallax-occlusion mapping, blob-shadow tier on smaller creatures. That is also why the framerate is more stable down there than in the open city.
What it means for the bench
A pre-owned PS4 running Bloodborne tells you a lot about its thermals. We hold the controller through the Mensis battle for ten minutes — if the fan hits the leaf-blower stage, the heat-paste needs reseating. About one in four bench PS4s comes off the shelf with fresh Arctic MX-4 before we list it.
Written from the bench in Hoxton. The Tavern dispatches indie & hardcore titles Mon–Sat. Browse the shelf.
