Unreal Engine 5 - Marcin Kepski

The End of 'Offline' Renders

The architectural visualization (ArchViz) industry has operated on a single paradigm for decades: model, light, and then wait. The long, agonizing process of offline rendering—using engines like V-Ray or Corona—defined workflows, budgets, and client expectations. A single animation second could take hours to render. Unreal Engine 5 has fundamentally broken this paradigm.

The conversation has shifted from "Can we render this?" to "How quickly can we walk through this?" The promise of real-time visualization is not new, but UE5 is the first time this promise has been fulfilled with *photorealistic* quality, thanks to two core technologies: **Nanite** and **Lumen**.

These two systems are not just iterative features; they represent a fundamental rewrite of how a graphics engine handles geometry and light. They directly address the two biggest bottlenecks in ArchViz: polygon count limits and the cripplingly slow process of "lightmap baking."

Understanding this shift is critical. It's not just about speed; it's about a new, interactive way of designing. When feedback is instant, designers can take more creative risks, clients can make more informed decisions, and the line between 3D model and finished product all but disappears.

NANITE: The Geometry Revolution

Virtual Micropolygon Geometry: Renders billions of polygons at high frame rates, effectively removing polygon budgets.
No More LODs: Eliminates the massive time sink of manually creating Levels of Detail (LODs) for assets.
Direct CAD/Scan Imports: Use full-fidelity assets, 3D scans, and complex CAD models without decimation.
Intelligent Streaming: Renders only the detail you can see, scaled to pixel-level accuracy.

LUMEN: Dynamic GI & Reflections

Real-Time Global Illumination: Fully dynamic GI and reflections mean instant feedback on lighting changes.
No More Lightmap Baking: The multi-hour (or multi-day) process of baking lightmaps is completely gone.
Software & Hardware RT: Scales from high-end (Hardware Ray Tracing) to consoles/mid-range PCs (Software).
Infinite Bounces & Skylight: Creates realistic, soft ambient lighting and accurate reflections automatically.

Photorealistic architectural interior rendered in Unreal Engine 5 with Lumen

LUMEN: Dynamic Lighting & Reflections

The New ArchViz Workflow

The workflow impact of Nanite and Lumen cannot be overstated. The traditional, linear pipeline—"model, UV, light, bake, render, post-produce"—is obsolete. The new workflow is cyclical, iterative, and interactive.

With **Nanite**, artists no longer spend 50% of their time on technical optimization. The painful process of retopologizing a high-poly sofa model or decimating a detailed CAD file is gone. Artists can import assets from Quixel Megascans, CAD programs, or 3D sculpting software *directly* and they just... work. This frees the artist to focus purely on composition and material definition.

With **Lumen**, lighting ceases to be a slow, technical calculation and becomes an *interactive design tool*. The artist can grab the sun, drag it across the sky, and watch in real-time as soft shadows and bounced light fill the room. Client feedback like "Can we see what this looks like in the afternoon?" is no longer a request for a new set of renders; it's a 10-second adjustment.

This shift "de-skills" the tedious, technical parts of the job (LODs, lightmap UVs) and "up-skills" the need for core artistic talent. When the tool gets out of the way, the quality of the artist's eye for composition, color, and light becomes the only thing that matters.

"We used to sell 5 static images and a pre-rendered fly-through. Now, we hand the client the .exe. They can walk around, change materials, and see the afternoon light. UE5 didn't just change our renders; it changed our final product."

— Director, Major Architectural Visualization Studio

Performance & The "Digital Twin"

While "minimal performance overhead" is the headline, the reality is nuanced. Nanite is incredibly efficient, but Lumen (especially with Hardware Ray Tracing) demands modern GPUs (RTX 30/40 series). However, the key is that the *development* cost (artist time) has plummeted, while the *hardware* cost (to run) is now the main consideration—a complete inversion of the old render farm model.

The business implication is the rise of the **"Digital Twin."** The same high-fidelity UE5 model used for client visualization can now be the foundation for a building's entire lifecycle. It can be used for virtual reality (VR) design reviews, real-time facilities management, and simulation data.

Studios are reporting 60-70% reductions in production time for interactive walkthroughs. The "time to final pixel" has collapsed from days (for an animation) to zero (for the interactive experience). This speed allows for a level of iteration and polish that was previously impossible.

The vulnerability? Artists must learn the engine. This isn't just a renderer; it's a game engine. To truly unlock its potential, ArchViz artists must now learn **Blueprints** (for interactivity like opening doors or changing materials), the advanced **Material Editor**, and scene optimization techniques.

Close-up of a complex 3D scanned statue in UE5 showing Nanite's detail

NANITE: Billions of Polygons in Real-Time

Strategies for Adoption

First, artists must abandon legacy thinking. Stop thinking in terms of "baking." Learn to light dynamically. This is a mental hurdle, not just a technical one. Trust the engine to handle the light bounces.

Second, master the ecosystem. Unreal Engine is not just a renderer. Success requires mastering **Quixel Bridge** for assets, the **Material Editor** for photoreal surfaces, and **Blueprints** for basic interactivity. The value proposition is no longer a static image; it's an *experience*.

Third, embrace high-fidelity assets. The days of faking detail with normal maps are fading. With Nanite, you can (and should) use the highest quality 3D scans and models available. The visual fidelity comes from real geometry, not shader tricks.

Fourth, focus on experience design. The new deliverable is an interactive application. This requires basic skills in level design, UI/UX, and optimization. The most valuable ArchViz artist is no longer just a 3D modeler; they are an *experience creator*.

The Interactive Age of ArchViz

Unreal Engine 5, powered by Nanite and Lumen, has fundamentally and permanently altered the architectural visualization landscape. It has replaced the slow, static, offline render with a fast, dynamic, and interactive experience.

The technical barriers to photorealism have been shattered. The artists and studios who thrive will be those who stop seeing UE5 as just a "renderer" and start using it as an "experience engine." The tedious work is gone; all that remains is the art.

Home

Blog

Showcase

Contact

Programming

3D & Visual Design

AI

Hardware & Tech

Unreal Engine 5: Real-Time Architectural Visualization