Stepping Into New Light – UE 5.8 migration

Light has always done the heavy lifting in Akolyta. A horror game lives or dies in the gap between what you can see and what you can’t — the sodium lamp guttering at the end of a corridor, the single bulb swinging in a derelict factory, the cold spill of light under a door that should have stayed shut. So when we talk about an engine upgrade, we are really talking about how we get to control that gap. Today we’re moving Akolyta onto Unreal Engine 5.8, and the reason sits right at the heart of how the game looks and runs.

Unreal Engine 5.8 launched on June 17 at Unreal Fest in Chicago. It’s the final major release of the Unreal Engine 5 line before Epic begins its transition to Unreal Engine 6, which makes it a stable, mature target to build the next stretch of Akolyta on. We made the jump for one feature in particular: a brand-new way of computing dynamic global illumination called the Lumen radiance cache.

01 — The upgrade

From CRYENGINE to the edge of UE5

Longtime backers will remember that Akolyta began on CRYENGINE before we moved the whole project to Unreal Engine 5. That decision was about the future of the toolset and about listening to you. Stepping up to 5.8 is the natural continuation of it: same engine family, same workflows our team already knows, but with the most capable version of Lumen we’ve had access to yet.

We didn’t chase the headline features for their own sake. Mesh Terrain, production-ready MegaLights, the rest of the 5.8 release — they’re impressive, but Akolyta is a tight, interior, narrative experience, not an open world. What we needed was control over light at a cost we could actually afford on the machines you play on. That’s exactly what the radiance cache gives us.

02 — The technology

What the radiance cache actually is

To understand what’s new, it helps to know how Lumen normally works. Full-quality Lumen computes indirect lighting through a high-quality Surface Cache — it’s gorgeous, fully dynamic, and it’s what made Unreal Engine 5’s lighting famous. It is also expensive. On lower-end hardware, it’s often the single thing standing between a project and a smooth frame rate.

Unreal Engine 5.8 introduces a new medium-quality global illumination mode that takes a different route. Instead of leaning on the Surface Cache, it builds a radiance cache out of irradiance fields and probe occlusion. In plain terms: rather than recalculating bounced light across every surface in view, the engine scatters a field of measuring points — probes — throughout the world, works out how much light arrives at each one, and then fills in the lighting on screen by reading from the probes nearby.

Here’s the sequence, step by step:

1. Scatter the probes. The engine places a grid of World Space Radiance Cache probes through the scene — think of them as tiny, invisible light meters suspended in the air around the player.
2. Measure the light. Each probe pre-calculates its irradiance — the total light reaching that point from every direction, including bounced and indirect light. This is the cache being filled.
3. Test for walls. Probe occlusion checks whether a wall, floor, or object sits between a probe and the surface being lit, so light can’t leak through solid geometry into a room it was never in.
4. Interpolate to the pixel. For any point on screen, the engine blends the readings from the surrounding probes to produce its indirect lighting — smooth, dynamic, and far cheaper than tracing it all from scratch.

The payoff is the part that mattered most to us. This path runs roughly twice as fast as full-quality Lumen while keeping the same art direction, and it’s tuned to hold 60 frames per second on a PlayStation 5 — with enough headroom to remain viable on lower-end PCs and current-generation handhelds where full Lumen was never a realistic option.

03 — Why it matters

Performance, where it counts for Akolyta

For a game like ours, this isn’t a graphics-bragging-rights upgrade. It’s a design one. Akolyta leans on fully dynamic lighting — light that can change while you watch it, because Marshall’s state of mind changes while you watch it. A baked, pre-computed lighting pass can’t do that; it locks the world into one fixed mood. The radiance cache lets us keep everything dynamic — lamps that fail, a room that darkens as his grip slips, a corridor that lights only as you enter it — and still hold a steady frame budget.

In a horror game, a frame-rate stutter doesn’t just look bad — it breaks the spell. Dread depends on momentum.

That’s the honest version of “best performance.” We’re not claiming Akolyta will run faster than every other game on earth. We’re saying the radiance cache gives us the best balance we’ve ever had between the lighting quality the game needs and a stable frame rate on the hardware you actually own — from a mid-range PC to a current-generation console. That balance is the thing that protects the experience. It means the lighting can do everything the story asks of it without the game choking to deliver it.

Development Status: On Track

We want to be clear about where things stand, because that transparency is the whole point of Early Access. The new build on Unreal Engine 5.8 is well underway and coming along nicely. The core project has been moved over, our environments are being re-lit on the new radiance-cache path, and the work that’s been in motion — Marshall Prime’s office, the 5.1 audio implementation, the environmental design of Gorenwille — is continuing right alongside the engine transition rather than being paused for it.

There’s still polish ahead, and we won’t pin a hard date to a build that isn’t ready — that’s a promise we’d rather keep than break. But the move is the unglamorous, foundational kind of work that pays off for everything that comes after it, and the team is genuinely happy with how the relit scenes are reading. The next time we show footage, you’ll be looking at Gorenwille under its new light.

Thank you, as always, for backing this the way you have. The slower, careful pace you’ve made possible is exactly what lets us get the small details right — and lighting is nothing but small details. More soon.