Convert OBJ to SH3D

A floor-plan project may require an OBJ model to appear as furniture in Sweet Home 3D. Importing the model into Sweet Home 3D and saving the project creates an SH3D file that preserves its placement, scale, and relationship to rooms and other furnishings.

What the OBJ format is

OBJ is a text-based format for polygon meshes. It can describe vertex positions, texture coordinates, normals, faces, groups, and material assignments. An accompanying .mtl file usually defines materials, while separate image files provide color, opacity, bump, or other texture maps.

Blender, Autodesk Maya, 3ds Max, SketchUp, MeshLab, CAD applications, and asset-conversion utilities use OBJ for exchanging models. The format is common for downloaded furniture, architectural assets, rendering meshes, and models transferred between 3D applications. OBJ does not reliably define units, animation, lights, cameras, or a complete scene.

What the SH3D format is

SH3D is the native project format of Sweet Home 3D. It stores a home-design project with its floor plan, rooms, furniture instances, dimensions, viewpoints, materials, and project settings. It is not a general-purpose mesh format and cannot replace OBJ for exchanging geometry with modeling software.

When Sweet Home 3D imports an OBJ, it creates a furniture item from the model. Saving the home as .sh3d stores the item in the context of that project, allowing it to be positioned, rotated, resized, raised, and viewed with the rest of the design. The result is a project conversion, not a standalone OBJ-to-SH3D mesh conversion.

How to convert OBJ to SH3D

1. Install the desktop edition of Sweet Home 3D from the official Sweet Home 3D website. No general online OBJ converter is a reliable substitute because SH3D is a Sweet Home 3D project format rather than a standard model-export format.
2. Place the OBJ, its matching .mtl file, and every referenced texture image in one folder. Preserve the filenames and relative paths used in the OBJ and MTL files.
3. Open Sweet Home 3D and select Furniture → Import furniture. Choose the .obj file and continue through the furniture-import wizard.
4. Use the preview to check the model orientation. Set its elevation and dimensions, and compare the displayed size with a known measurement because OBJ does not impose a universal unit system.
5. Enter a furniture name and, where available, select a catalog category and icon. Finish the wizard and place the new item in the floor plan.
6. Open the furniture properties to adjust position, rotation, elevation, and size. Save the project with File → Save as and use the .sh3d extension.

The official Sweet Home 3D online version may be useful for ordinary project editing where its available import and save features meet the requirement, but the desktop edition is the safer choice for importing external models and diagnosing texture or scale problems. Third-party online converters generally output formats such as GLB, STL, or DAE, not a valid SH3D project.

Preparing the model

For models that import incorrectly, open the OBJ in Blender or MeshLab before importing it into Sweet Home 3D. Apply object transforms, verify face orientation and normals, remove hidden geometry, repair non-manifold areas, and export a cleaned OBJ with its MTL and image textures. Triangulating problematic faces can resolve preview or rendering errors.

Keep materials simple when possible. Image-based diffuse or color textures are more dependable than procedural shaders, complex transparency, unsupported reflection settings, or absolute texture paths. If the model appears untextured, inspect the OBJ and MTL references in a text editor and confirm that texture filenames, capitalization, and relative paths match the actual files.

Quality and compatibility limits

Sweet Home 3D imports the model as furniture, so OBJ cameras, lights, animation, rigs, scene hierarchy, and application-specific settings do not transfer. Multiple OBJ groups may also become a single furniture item rather than independently editable parts.

Very dense meshes can make Sweet Home 3D slow to navigate and render. Create a lower-polygon copy in Blender or MeshLab before importing, and retain the high-resolution OBJ separately for rendering or later editing.

Check the imported dimensions against doors, walls, or another known object. If the scale is wrong, correct the dimensions in the import wizard or furniture properties rather than assuming that the source application and Sweet Home 3D interpreted OBJ units identically.

Retain the original .obj, .mtl, and texture files alongside the .sh3d project. The SH3D file is intended for Sweet Home 3D home-design work; the source files remain necessary for editing the mesh or sharing it with other 3D applications.