Importing an Unreal Engine Scene with Datasmith: Scale and Surface Checks

What you’ll learn in this guide

When importing scenes from different 3D design applications into Unreal Engine, Datasmith converts geometry and scene data. However, you shouldn’t assume that every object will look and behave exactly as it did in the source application after import. In this guide, you’ll verify scale and naming, investigate possible causes of invisible surfaces, review lightmap UVs, and check lights and physics settings.

These checks are especially useful for architectural visualization and interior scenes. Thin walls, single-sided ceilings, complex transform hierarchies, and static lightmaps can all lead to unexpected results after import. Some issues can be addressed in Unreal Editor, while geometry-related problems may be better fixed at the source.

Requirements and scope

You’ll need a source 3D scene, the Datasmith import workflow, and Unreal Editor. Epic’s documentation discusses applications such as 3ds Max, Cinema 4D, Rhino, and SketchUp. The file format and source application can affect naming and import results.

This tutorial is based on guidance in Epic’s documentation for Unreal Engine 5.0, 5.1, and 5.2. Keep in mind that features and requirements may differ across version documentation. The sources don’t specify particular account requirements, hardware tiers, or licensing conditions. If you plan to use Nanite, check the version requirements separately: the UE 5.0 notes state that Nanite on Windows requires DX12 and does not support DX11. The UE 5.1 notes state that Shader Model 6 must be enabled with DirectX 12 for Nanite.

Post-import checks

1. Verify scale and the transform hierarchy. Unreal Engine expresses distances in centimeters. If the source application uses a different unit, Datasmith automatically adjusts the scale to preserve the objects’ real-world dimensions. In Epic’s example, an object defined as 10 units in inches in the source scene becomes 25.4 world units long in Unreal Engine. So don’t manually rescale a scene just because the units differ; check the imported dimensions first.

   If the scale or position looks unexpected, inspect non-uniform scaling on parent objects and custom pivot transforms. Using these together can make coordinate conversions more complex, potentially producing results that differ from the source scene. Epic notes that simplifying the source scene hierarchy may help in this situation.

2. Distinguish asset labels from names. Datasmith uses naming information from the source file wherever possible. Even so, the static mesh label in the Content Browser, the asset filename on disk, and the Actor name in the Level may not match. Filenames on disk must be unique; when objects with the same name are imported, numeric suffixes may be added to Actor names to make them unique.

   Bear this distinction in mind when searching for and organizing content. In workflows that access assets through Blueprint or Python, remember that the label displayed on screen isn’t necessarily the same as the filename.

3. Check normal orientation on missing surfaces. Unreal Engine may cull triangles facing away from the camera. Single-sided geometry with no thickness that appears visible from both sides in the source application may be invisible from some angles in Unreal Engine. Move around the model to see whether the surface appears from another viewpoint. This doesn’t necessarily mean the geometry failed to import.

   A more reliable approach for objects that need to be visible from every direction is to give them thickness in the source application and orient their normals outward. For surfaces that should only be visible from one side, flipping the normal in the source application is one option. Applications such as 3ds Max, Cinema 4D, Rhino, and SketchUp may offer viewport views that help identify back-facing triangles; consult the documentation for the application you use for details.

4. Don’t treat two-sided materials as a universal fix. A two-sided material can make a surface render from both directions. However, Epic warns that this can cause visual artifacts with Static or Stationary lighting; both sides may use the same area in the lightmap texture. If the problem is caused by normals, fix the geometry in the source application whenever possible.

   Changes to surface orientation made on a static mesh in Unreal Editor may be lost when the source scene is updated and the Datasmith Scene Asset is reimported. If you also plan to modify the source scene, make the geometry fix there as well.

5. Inspect lightmap UVs. For static lighting, every static mesh needs suitable UV coordinates for its lightmap. Overlapping triangles in 2D texture space can prevent lighting and shadow information from being stored correctly, causing lighting artifacts. Datasmith runs an automatic UV unwrapping system for each static mesh it imports and creates two new UV sets. The first splits the surface into 2D islands; the second arranges those islands without overlap to prepare the layout for use in a lightmap.

   If lightmap UV channels have already been prepared in 3ds Max, also review Epic’s Datasmith for 3ds Max guide. Checking how automatically generated UVs are used alongside the existing layout in the source scene can help avoid surprises during later lighting work.

6. Review light types and physics needs. Lights from supported source formats can be converted to suitable light types in Unreal Engine, including Point, Spot, Rectangular Area, and Directional lights. Some applications’ plane or volume lights have no direct equivalent in Unreal Engine; Datasmith can mimic their behavior with a custom Blueprint class.

   Datasmith doesn’t configure physics settings for static meshes by default. If objects in the scene need physics behavior, configure those settings in Unreal Editor. Epic’s documentation also provides separate guidance on setting up collision for static meshes, so don’t treat collision requirements as the same thing as physics settings.

Common mistakes

• Manually scaling the model as soon as you notice a unit difference: Account for Datasmith’s automatic scale conversion and verify dimensions after import.

• Assuming an invisible surface failed to import: Move the camera to different angles and inspect the surface normals and geometry thickness.

• Making every surface use a two-sided material: Consider the lightmap artifacts that may occur with Static or Stationary lighting.

• Assuming physics settings are configured automatically: The source documentation says that physics isn’t configured by default for static meshes; configure it separately in the Editor if needed.

• Assuming Editor fixes will be preserved when the source scene changes: Reimporting may remove some geometry fixes that aren’t present in the source scene.

Impact on architecture and archviz workflows

For architects, interior designers, and visualization teams, these checks can help identify the causes of visibility and lighting issues in scenes imported into Unreal Engine more quickly. Separating normal and thickness problems that can be fixed during modeling from material or lighting adjustments made in the Editor reduces rework. In projects that use lightmaps, UV layout should also be part of the import review.

For projects considering Nanite, verify the DX12 and Shader Model 6 requirements against the documentation for your Unreal Engine version. These sources don’t provide information about hardware tiers, pricing, or licensing conditions, so research those separately before starting a project.

Next steps

During your first review, classify issues according to whether they should be fixed in the source scene or in Unreal Editor. For normal, thickness, and transform hierarchy issues, return to the source and make the fix; if you use lightmaps, check the UV layout. If physics behavior is required, configure the static meshes in Unreal Editor. Before each reimport, check whether Editor changes that aren’t present in the source scene will be preserved.

Sources and license

This tutorial has been adapted into Turkish from Epic Games’ official “Datasmith Import Process,” “Unreal Engine 5.0 Release Notes,” “Unreal Engine 5.1 Release Notes,” and “Unreal Engine 5.2 Release Notes” documents. The source texts are identified as free to use for this work.