SimLab OBJ Exporter for SolidWorks: Preserve Materials, Textures, and Geometry

SimLab OBJ Exporter for SolidWorks: Preserve Materials, Textures, and GeometryExporting 3D models from SolidWorks into the OBJ format is a common need when moving designs into rendering engines, game engines, AR/VR platforms, or other 3D tools. The SimLab OBJ Exporter for SolidWorks aims to make this transfer accurate and efficient, keeping not only geometry but also materials, textures, and scene hierarchy intact. This article walks through what the exporter does, why preserving materials and textures matters, how to use the plugin effectively, common pitfalls and solutions, and optimization tips for best results.

Why OBJ + MTL matters for SolidWorks workflows

• The OBJ file format stores polygonal geometry (vertices, faces, normals, UVs) in a widely supported, text-based format.
• The companion MTL file describes surface appearance (materials) and references image textures used by those materials.
• Many real-time engines, renderers, and 3D viewers accept OBJ+MTL, making it a universal interchange format.
• Preserving materials and textures reduces manual rework—saving time and ensuring visual fidelity across tools.

Key takeaway: OBJ with MTL keeps geometry and basic material assignments portable across many 3D applications.

What SimLab OBJ Exporter does differently

SimLab’s exporter plugs into SolidWorks and adds an export path that focuses on retaining as much scene information as the OBJ/MTL pair can represent:

• Exports polygons with normals and UVs to preserve shading and texture mapping.
• Converts SolidWorks appearances/material assignments into MTL-compatible material definitions.
• Exports linked texture images (diffuse, opacity, bump/normal maps where supported) and updates MTL references.
• Preserves object/assembly hierarchy by creating grouped or named objects in the OBJ, aiding scene reconstruction.
• Offers export settings to control units, scale, coordinate system (Y-up vs Z-up), and polygon tolerance.
• Optionally triangulates or preserves quads depending on downstream requirements.

Key takeaway: SimLab focuses on minimizing loss of visual data when converting SolidWorks parts and assemblies to OBJ/MTL.

Preparing SolidWorks files for best export results

1. Clean and simplify geometry

   • Remove tiny features, duplicate faces, or unnecessary construction geometry that won’t affect visuals but increase polygon count.
   • Use SolidWorks Defeature or Smart Simplify for large assemblies.

2. Standardize materials and appearances

   • Replace procedural or complex appearance setups with simple texture-based materials where possible.
   • Consolidate similar materials to avoid many near-identical MTL entries.

3. Create and assign UV-friendly textures

   • If you rely on texture mapping, ensure parts have proper UVs (SolidWorks may generate projected UVs during export; test and adjust if necessary).
   • Use high-quality, power-of-two textures for engines that prefer them (512/1024/2048 px).

4. Name parts and subassemblies clearly

   • Clear naming helps SimLab produce readable OBJ object/group names and makes organizing in downstream tools easier.

Step-by-step: Export using SimLab OBJ Exporter (typical workflow)

1. Install the SimLab OBJ Exporter for SolidWorks and restart SolidWorks.
2. Open your part or assembly in SolidWorks.
3. From the SimLab toolbar/menu, choose “Export to OBJ” (or similar command).
4. Configure export options:
   • Output folder and base filename
   • Include MTL file (enable)
   • Export textures (copy images into an exported textures folder)
   • Coordinate system (match target application)
   • Units and scale (ensure consistency with destination)
   • Polygonization tolerance / mesh resolution
   • Triangulate meshes (if required by the target)
   • Preserve hierarchy / group by assembly
5. Check material mapping options:
   • Map SolidWorks appearances to MTL material properties (diffuse color, specular, opacity).
   • Link image textures (diffuse/albedo, opacity, bump/normal where available).
6. Run export and inspect the output directory:
   • .obj file (geometry, groups, normals, UVs)
   • .mtl file (material definitions)
   • texture image files (JPEG, PNG, or original formats)
7. Test import into target application (e.g., Blender, Unity, Unreal, Marmoset, three.js) and verify:
   • Geometry integrity and normals
   • Material color and texture placement
   • Object grouping/hierarchy
   • Scale and orientation

How materials and textures are mapped to MTL

• Diffuse/albedo: SolidWorks appearance color or diffuse texture becomes the MTL’s map_Kd (diffuse texture) or Kd (diffuse color).
• Specular/roughness: MTL supports simple specular parameters; exporters approximate SolidWorks metallic/roughness workflows by setting specular exponent or using texture maps when available.
• Opacity: Alpha maps are exported and referenced using map_d (or map_opacity) where the target parser supports it.
• Normals/bump: Traditional MTL doesn’t have a standardized normal map slot; exporters may include a bump map reference (map_bump) which many importers understand.
• Texture paths: The exporter copies textures into the output folder and writes relative paths in the MTL, ensuring textures load on import.

Note: Because MTL is less expressive than modern PBR material systems, some properties (e.g., complex layered materials, procedural reflections) are approximated.

Common issues and solutions

• Missing textures after import
  • Ensure textures were copied into the export folder and MTL references relative file names. If not, enable “export textures” and re-export.
• Incorrect orientation (flipped normals or wrong up-axis)
  • Toggle Y-up vs Z-up in export settings; if normals are reversed, enable “recompute normals” or flip normals in the target app.
• Material looks flat or different
  • OBJ/MTL is not PBR-native. Recreate or tweak materials in the target renderer using exported textures (albedo, roughness, normal) if available.
• Large file sizes
  • Reduce texture resolution, use compressed formats (JPEG for albedo), or increase polygonization tolerance to lower mesh density.
• Overly dense meshes from small features
  • Use Defeature, simplify geometry, or export parts separately and retopologize if needed.

Optimization tips for different targets

• For real-time engines (Unity, Unreal)
  • Triangulate meshes, use power-of-two texture sizes, bake complex materials into albedo/normal/roughness maps, and combine small parts into larger meshes where suitable.
• For offline renderers (KeyShot, V-Ray, Blender Cycles)
  • Preserve high-quality normals and UVs, keep higher-resolution textures, and use layered materials in the renderer if needed.
• For web viewers (three.js, Sketchfab)
  • Reduce polygon count, compress textures, and ensure material maps are referenced with relative paths. Consider converting to glTF later for more expressive PBR support.

When OBJ/MTL isn’t enough — alternatives

• glTF / GLB: Modern, compact, PBR-friendly, includes embedded textures and supports PBR workflows natively. Consider exporting to glTF when possible.
• FBX: Supports more material attributes, animations, and hierarchy details; widely supported in game engines and DCC apps.
• Native formats or dedicated pipelines: For highest fidelity, use native exchanges or direct connectors (e.g., SimLab’s other exporters or dedicated SolidWorks-to-engine plugins).

Key takeaway: Use OBJ for broad compatibility and quick transfers; switch to glTF or FBX when you need richer material/scene fidelity.

Quick checklist before exporting

• [ ] Geometry cleaned and defeatured
• [ ] Parts and assemblies clearly named
• [ ] Textures prepared (resolved UVs, appropriate sizes)
• [ ] Materials simplified or mapped to textures
• [ ] Export settings: units, axis, triangulation verified
• [ ] Textures set to be exported and MTL generation enabled

Conclusion

The SimLab OBJ Exporter for SolidWorks is a practical tool when you need reliable, widely compatible exports that preserve geometry, material assignments, and texture references. While OBJ/MTL has limitations compared with modern PBR formats, careful preparation of your SolidWorks model and correct exporter settings let you retain much of the visual fidelity and reduce rework in downstream applications. For workflows that demand full PBR materials, consider exporting to glTF/FBX or supplementing OBJ exports with baked texture maps.