How to Prepare and Import a 3D CAD Model

RoadScope’s 3D view combines two different layers. Google’s photorealistic basemap supplies terrain, buildings, and vegetation; it is imagery and cannot be edited. A model you import is your own separate asset placed over that basemap. Only imported models appear in the 3D Models panel and can be moved, rotated, scaled, shared, or deleted.

Choose the Right Format

GLB (.glb, preferred direct format; up to 200 MB) — Use this when you need embedded materials or textures. Export plain glTF 2.0 with embedded JPEG/PNG images. Do not use KHR_draco_mesh_compression, EXT_meshopt_compression, KHR_texture_basisu, EXT_texture_webp compression.

Convertible CAD and mesh formats (up to 50 MB) — .stl, .obj, .step, .stp, .iges, .igs are converted to GLB. STEP is preferred when available because it carries CAD surfaces cleanly into tessellation; IGES is a fallback. STL has no units, colors, or textures. OBJ companion MTL and texture files are not imported.

Conversion turns exact CAD surfaces into triangles and is therefore lossy. More parts, tiny features, and detailed curves increase conversion time and output size. Start with Balanced quality; use Detailed only when curved surfaces require it.

Prepare the Source Model

1. Remove hidden internals, fasteners, and small features that do not affect route or site decisions. For assemblies, export only the needed configuration.

2. Confirm dimensions in the source tool. GLB uses metres. STL has no unit declaration, so record whether its numbers mean mm, cm, m, in, or ft; set Model units in RoadScope after import.

3. Confirm orientation. glTF is Y-up. Apply transforms before export and arrange the expected front direction so only final heading, tilt, or roll adjustments are needed.

4. Put the model origin near the asset and at its intended ground contact. A distant or elevated origin makes placement and grounding harder.

5. Preserve CESIUM_RTC or latitude/longitude extras only when the export is genuinely georeferenced. Otherwise RoadScope places the model at the current map view for manual positioning.

Export Recipes

SolidWorks / Autodesk Inventor — Suppress internal components and minor hardware, then export the selected part or simplified assembly as STEP AP214/AP203. Use a GLB-capable plug-in only when you have verified it emits plain glTF 2.0.

Fusion — Prefer STEP for design geometry. Use STL only for simple untextured meshes and remember that STL loses units and materials.

FreeCAD — Select the required solids, verify document units and placement, and export STEP. IGES is a fallback when STEP is unavailable.

AutoCAD-compatible tools — Export STEP, IGES, STL, or OBJ only when your product and version provide that option. RoadScope does not accept DXF or IFC as 3D model files.

Blender — Apply modifiers and all transforms, use Metric units with scale 1.0, place the origin at ground level, and export glTF Binary (.glb). Disable Draco/Meshopt compression and embed JPEG/PNG textures.

Photogrammetry tools — Export a binary GLB in metres with embedded JPEG/PNG textures. Keep WGS84 CESIUM_RTC or latitude/longitude metadata for automatic placement, use ground control appropriate to the survey, decimate large meshes, and tile long corridors.

Import, Review, and Place

Open the 3D view, open the 3D Models panel, and choose Import. The guide beside the panel title is available before you select a file.

Preflight checks the format, size, GLB structure, geometry, dimensions, textures, compression, and georeference metadata it can inspect. Blocking errors must be fixed. Warnings explain risks; processing notes describe conversion or normalization that requires your approval.

A georeferenced GLB is placed at its embedded real-world location. A file without supported georeferencing starts at the current 3D map view. Drag it to the site, then use Properties to set model units, scale, heading, tilt, roll, and height offset. Models sit relative to the photorealistic mesh, so a small height adjustment may still be needed.

Verify After Import

The Verified renderable badge means the file RoadScope serves passed server checks for valid GLB structure, readable triangle geometry, and supported data. If an optimized or normalized copy fails, RoadScope may serve a verified fallback and says so on the card.

Verification does not prove visual correctness. Fly to the model and confirm its location, known dimension, orientation, ground contact, complete geometry, and textures. Use Preview or Measure when useful. If verification fails, follow the reason on the model card, repair or simplify the source, and re-export.

Troubleshooting

Wrong scale — Set the source units in Properties, or re-export GLB in metres. Floating or buried — fix the source origin and adjust Height offset. On its side — correct axes/apply transforms, then adjust tilt/roll. Missing textures — use one GLB with embedded JPEG/PNG textures. No automatic placement — drag from the current view or re-export with supported georeferencing.

Does not render — remove Draco, Meshopt, KTX2/Basis, and WebP compression. Conversion fails or output is oversized — simplify assemblies, remove tiny features, lower tessellation quality, or split the model. Curves lose detail — increase quality only after simplifying the source.