The Twinmotion round-trip: Datasmith into Unreal

10:00 · Brief Other people's geometry

The archviz pipeline is a translation problem. Architects work in CAD and BIM tools that care about tolerances and revisions; game engines care about triangles, UVs, and frame time. Datasmith is Epic's translation layer — it carries geometry, materials, hierarchy, and metadata from those worlds into Unreal, and Twinmotion sits on the same foundation as the fast, designer-friendly front end. Project 2 (see the Projects tab) lives in this pipeline for the next five weeks.

What Datasmith preserves — and what it can't

Expect the scene hierarchy, instancing, and material assignments to arrive largely intact; expect to do surgery on everything a CAD tool never had to think about. The reliable wound list: object names like Extrusion_2847, no collision anywhere, lightmap UVs missing or overlapping, pivots at the world origin instead of on the object, and glass that imports as a gray slab. None of these are bugs — they're the difference between a drawing and a game engine. Budget for cleanup; the brief's "pipeline notes" deliverable is exactly this ledger.

Archviz is photography

What a client buys is not the model — it's the image. Which makes this week secretly a photography class: eye-level cameras (not drone-hovering god views), verticals kept vertical, wide but honest lenses in the 18–35 mm range, and depth of field used to direct the eye rather than to show off. In UE that language lives in the Cine Camera Actor, with real-world focal lengths and apertures, and in 5.8's rendering path for stills and flythroughs with accumulated, film-quality depth of field.

Scan versus model

The industry's live question, and this week's discussion: capture is getting so good that sometimes the right move is to not model at all. That's where Gaussian splatting comes in.

10:45 · Guided lab Round trip: Twinmotion → Unreal → camera

Everyone runs the same pipeline end to end today with a provided architectural model, so the workflow is proven before you commit to your own Project 2 subject.

1. Dress the scene in Twinmotion

   Open the provided model in Twinmotion. Spend twenty minutes doing what Twinmotion is best at: drag-and-drop materials, vegetation, a time of day. Note how fast iteration feels — that speed is why the pipeline starts here.

2. Export for Unreal

   Export the scene from Twinmotion as a Datasmith file (via its export options for Unreal / Datasmith). Note what the export dialog offers to include — that list is exactly what will and won't survive.

3. Enable Datasmith in UE

   In a fresh UE project (FMX430_Archviz — zip a clean dated copy before anything is imported): Edit → Plugins, enable the Datasmith importer plugins, restart if prompted.

4. Import and inspect the damage

   Import the Datasmith file from the main toolbar's Datasmith import. Then inspect like a surveyor: open the content browser folders it created, check names, select meshes and look for collision and lightmap UVs in the static mesh editor. Write down the top five problems — this list drives the AI lab.

5. Fix a few by hand first

   Rename a handful of assets properly, generate collision on one mesh in the static mesh editor, fix one material assignment. You need the manual feel for each fix before you delegate it at scale.

6. Shoot a hero still

   Place a Cine Camera Actor at standing eye height. Choose a focal length deliberately (start near 24 mm), level the horizon, compose with foreground. Set aperture and focus distance in the Details panel so depth of field serves the composition. Render a high-resolution still.

7. Block a flythrough

   Rough out a 20–30 second camera move through the space (Sequencer basics on the projector — full cinematics come later in the course). Slow is professional; fast is a video game trailer.

8. Back everything up

   A dated zip on your cloud drive, with your import problem list saved alongside — it's the seed of Project 2's pipeline notes.

12:00 · Workbench Practice, unhurried

No new material. You work on your own file while I circulate — this is the hour where the technique from the guided lab stops being something you watched and becomes something you can do.

1. Finish the lab on your own work

   The guided lab was built on the class example. Now do it on the piece you are actually submitting. That second pass is where it sticks.

2. If you fell behind, catch up here

   This is what the hour is for. Say so and I will come to you — do not spend it quietly stuck.

3. If you are ahead, go deeper

   Take the optional extensions from the lab, or push the piece further than the brief asks. Nothing graded depends on them.

4. Ask the AI TA anything

   The tutor on the course site is open all term for questions about how and why. It explains; you build. No agents in the work until Week 9.

1:15 · Crit / share Hero stills

Everyone puts their one hero still on the projector. We read them as photographs: where does the eye go, are the verticals vertical, what is the depth of field for? Declare your Project 2 subject — an unbuilt or reimagined space — before you leave. And remember the schedule: Project 1 is due at crit next week, so this weekend serves two masters.

Homework — due before Week 6

Resources

• Twinmotion — downloads and learning resources for the front half of the pipeline.
• Epic Developer Community — Learning — Datasmith and archviz guided courses live here.
• Kerbl et al., 3D Gaussian Splatting — the course's landmark paper; this week's required skim.
• Splats in UE, 2026 — the production-side view of the scan-vs-model question.
• Project 2 brief — deliverables and assessment for Architectural Visualization.