Importing photogrammetric models (Batch OBJ)

3DSC ships a Batch OBJ Import command that brings several Wavefront .obj models into Blender in a single pass, preserving the original alignment, scale and (optionally) the geographic shift stored at scene level. Use this recipe when an archaeological or architectural dataset is delivered as a set of tiles or as a series of textured objects that must coexist in the same Blender scene.

See also

For the rationale behind coordinate shifting (why georeferenced meshes need a scene-level offset, when to enable it and when not to), see Coordinate shifting in 3DSC.

This page is the canonical tutorial for the Batch OBJ Import button exposed by the Importers panel of 3DSC. The short description of the button in the panel reference (Importers) covers the UI; the recipe below covers the end-to-end workflow.

When to use this recipe

Reach for the Batch OBJ flow when you have:

• A photogrammetric model split into multiple tiles exported from Metashape, RealityCapture, or any other photogrammetric suite.

• A set of distinct textured objects (e.g. individual finds, blocks of a wall, stratigraphic units processed separately) that belong to the same site and must share a coordinate frame.

• A folder of legacy .obj exports you need to round-trip through Blender, keeping consistent naming and grouping.

For a single .obj file the standard Blender importer (File → Import → Wavefront (.obj)) is usually enough; the Batch OBJ Import flow is optimised for folder-level ingestion.

Prerequisites

Before launching the importer, make sure that:

• The source folder contains the .obj files plus their companion .mtl files and the referenced texture images (typically .png or .jpg). The .mtl files are read by Blender to recreate the material slots; missing textures will not break the import but will yield untextured materials.

• All models share a common reference frame. Mixed local / georeferenced models in the same batch will land at incompatible positions in the Blender viewport.

• If the models are in absolute (UTM or other projected) coordinates, a SHIFT.txt file is available — either inside the source folder or already loaded into the scene through the Shifting panel. See 3DSC4Metashape for the canonical SHIFT.txt syntax (EPSG::NNNN X Y Z).

• The Blender file is saved on disk before the import. Saving the .blend first lets Blender resolve relative texture paths reliably.

Step-by-step workflow

1. Open the 3DSC Importers panel — in the Blender 3D Viewport sidebar (N key) switch to the 3DSC tab and expand Importers.

2. Click “Batch OBJ Import” — the button is labelled Multiple objs in the panel. A file browser opens, anchored to the last used location.

3. Navigate to the source folder — open the folder that contains the .obj files and their .mtl / texture companions. You do not need to multi-select the files: the operator scans the active folder and imports every .obj found at its top level.

4. Review the import options on the right side of the file browser. The defaults work for most photogrammetric exports (Z Up / Y Forward). If your source pipeline uses a different axis convention, set the matching values from the drop-down menus before confirming.

5. Apply the geographic shift (when applicable) — if the models are georeferenced, enable the Shift coordinates option so that 3DSC subtracts scene.BL_x/y/z_shift from the model vertices on the way in. The shift values come from the Shifting panel or from a SHIFT.txt file placed alongside the .obj files. Leave the option off for purely local-coordinate datasets.

6. Confirm the import — click Import OBJs (the confirm button at the bottom-right of the file browser). 3DSC iterates over the folder and ingests each .obj as a separate Blender mesh.

Output

After a successful import you will find, in the Blender Outliner:

• A new collection named after the source folder, grouping every imported mesh in a single logical container.

• One mesh object per source .obj file, each retaining the base name of the source file. Material slots are populated from the matching .mtl.

• An optional empty object acting as the group anchor when shift values have been applied, so the entire batch can be translated or parented as a unit without losing relative alignment.

Remember

By default 3DSC sets imported meshes to Bounds display mode for performance. Switch to Textured in the Object → Viewport Display panel to see the photogrammetric materials.

Troubleshooting

• Models stack at the world origin (0, 0, 0) — the Shift coordinates option was probably left off while the source .obj files store absolute UTM coordinates. Either re-run the import with the option enabled, or set the scene shift through the Shifting panel and re-import.

• Models appear scattered far from the scene origin — the opposite case: shift was applied, but the source files are already in local coordinates. Disable Shift coordinates and re-import.

• Materials are loaded but textures are missing or pink/magenta — Blender could not resolve the texture paths declared in the .mtl. Confirm that the texture files sit in the same folder as the .obj (or that the .mtl uses relative paths). Saving the .blend before importing helps Blender resolve relative paths consistently.

• Some .obj files are skipped — only files at the top level of the source folder are picked up. Move nested .obj files up one level, or run the import once per subfolder.

• Axes look swapped (model lying on its side) — change the Forward / Up axis settings in the file-browser sidebar and re-import; the defaults match Blender’s convention, not every photogrammetric exporter.

Related recipes

• Importers — short reference description of every button in the Importers panel.

• Shifting — how to configure the scene-level BL_x/y/z_shift values consumed by this importer.

• Importing CAD files (DXF) — sibling recipe for CAD/DXF vector imports, which also honours the scene shift.

• 3DSC4Metashape and 3DSC4RealityCapture — pipelines that typically produce the multi-tile .obj datasets handled by this recipe.