Datasmith & Import Pipelines

Datasmith is a collection of tools and a file format that bring pre-constructed scenes and complex assets into Unreal Engine. It exists because game engines were built to consume game assets, not BIM files - and architecture, product design and engineering all needed a faithful on-ramp. Epic built Datasmith to be that on-ramp, and it is free.

Think of it as a translator that speaks both languages. On one side it reads the rich, structured data your design tool holds; on the other it writes the actors, static meshes, materials and textures Unreal understands. Crucially, it tries to preserve four things, not just shape. Geometry comes across as tessellated meshes, one per source element. Materials come across as real Unreal materials - your source colours and textures mapped onto a physically based master material you can then refine (Module 3). Hierarchy comes across intact - your Revit categories, Rhino layers or SketchUp groups become a matching folder and actor structure, so a wall is still findable as a wall. And metadata comes across as tags on each actor: room names, Revit parameters, IFC properties - the BIM intelligence, riding along so you can filter, colour or script by it later.

The container for all of this is a single Datasmith Scene asset that Datasmith drops into your project. Think of it as the manifest of the import: it remembers what came from where, and it is the thing you later ask to re-import or sync when the design changes. That is why Datasmith is not just an importer but a pipeline - it keeps a relationship with the source rather than dumping a pile of disconnected meshes and forgetting where they came from. Module 2 lesson 4 leans heavily on this.

Be honest about the limits, though. Datasmith gives you geometry plus data, not a live copy of your BIM application. Animations, Revit-specific views, construction constraints and proprietary parametric behaviour do not survive the crossing, and UVs may need work for good texturing. Treat the import as a faithful snapshot of the model's shape and data at a moment in time - which is exactly what you want as a starting point for a real-time scene, and the four lessons of this module take that snapshot from raw to production-ready.

Datasmith supports the tools architects and designers actually use, through two mechanisms: exporter plugins you install into the source application, and direct importers built into Unreal that read a native file.

The headline supported sources are Autodesk Revit, 3ds Max, Rhino (and Grasshopper definitions), SketchUp Pro, and Navisworks - each via a dedicated Datasmith exporter or plugin. Beyond those, Datasmith reads a long list of CAD and interchange formats directly: IFC (the open BIM standard), plus engineering formats like STEP, IGES, JT, SolidWorks, CATIA and DWG through its CAD importer. So whether your model is a Revit federated BIM, a Rhino concept, a SketchUp massing study or an IFC handed over by a consultant, there is a route in.

A practical note on which route to pick. If your tool has a dedicated exporter (Revit, Max, Rhino, SketchUp, Navisworks), prefer it - the exporter understands that application's materials and structure best and gives the richest, most faithful result. Fall back to the generic CAD/IFC importer when no dedicated exporter exists, or when a consultant hands you a neutral file. And remember Datasmith is free but version-sensitive: the exporter plugin must match both your source-app version and your Unreal version, so grab the right build from Epic when you set up. Twinmotion, Epic's friendlier sibling, uses the very same Datasmith pipeline under the hood - so what you learn here transfers straight across.

Datasmith offers two workflows, and knowing when to use each is half the skill.

The first is the .udatasmith file - a one-shot export. In your source app you run the Datasmith exporter, which writes a .udatasmith scene file plus a folder of textures and geometry. In Unreal you press Import, point at that file, and Datasmith builds the scene. It is explicit and portable: the file is a snapshot you can archive, hand to a colleague, or version. When the design changes, you re-export and re-import, and Datasmith intelligently merges - updating changed elements while trying to preserve the Unreal work you layered on top.

The second is Direct Link - a live connection between the running source application and the running Unreal (or Twinmotion) session, with no file in between. You establish the link once; then each time you hit Sync, Datasmith pushes the current state of the model straight into your scene. No exporting, no file juggling - the design tool and the real-time scene stay coupled. This is transformative for iterative design: an architect nudges a wall in Revit, syncs, and the change is standing in the Unreal walkthrough seconds later. Direct Link is the closest thing to a living link between your BIM model and your immersive scene, and Module 2 lesson 4 is devoted to using it well.

Which to choose? Use Direct Link while the design is active and you are iterating tightly with the source app open. Use the .udatasmith file when you want a portable, archived snapshot, when the source machine and Unreal machine are different, or when handing work off. Many studios use both: Direct Link during design, a final file export to freeze the delivered version. A practical caveat with Direct Link is that it needs both applications open and healthy at once, which is demanding on a single machine when the source model is heavy - so if Revit and Unreal are fighting over your RAM, the file route is often the calmer choice. Twinmotion, again, uses the identical Direct Link mechanism, so a designer can push a Rhino model to Twinmotion for a fast look and to Unreal for the deep work from the same live link.

Here is the whole pipeline in one concrete pass, using Revit as the example - the steps are nearly identical for Rhino or SketchUp.

One: install the Datasmith Exporter for Revit that matches your Revit version, and confirm your Unreal project is a real-time or archviz-flavoured project. Two: in Revit, set up the 3D view you want to send - Datasmith exports what is visible, so hide what you do not need and this is your first, free optimisation. Three: either click Export > Datasmith to write a .udatasmith file, or start Direct Link to sync live. Four: in Unreal, open the Datasmith import options and press Import (or Sync). You will see options for how to handle collision, lightmap UVs, metadata and tessellation - accept sensible defaults for a first pass. Five: Datasmith drops a Datasmith Scene asset and populates your level with the model, organised into folders that mirror your Revit categories. Six: save, and walk it in the viewport with the real-time workflow from Module 1.

What you now have is a live, navigable building in Unreal, with materials as a starting point and BIM metadata attached to every element. It will not be finished - the next three lessons are about preparing the source so the import is clean, fixing tessellation and artifacts, and organising and updating the scene as the design evolves. But the bridge is crossed, and it took minutes, not days.

One more habit worth forming from the very first import: read the import options rather than blindly accepting them. The two that matter most for architecture are lightmap UVs (whether Datasmith generates a second UV set for baked lighting - useful if you are not going fully dynamic) and tessellation (how finely CAD surfaces are diced, covered in depth in lesson 2.3). You do not need to master them on day one, but knowing they exist stops the import feeling like a black box. And because Datasmith remembers your choices on the Datasmith Scene asset, the settings you pick become the baseline every future re-import inherits - so a thoughtful first pass pays dividends across the whole life of the project.