You finished the walls or a part in FreeCAD, hit export, and Blender either swallowed the model as one blob, laid it on its side, or showed a city-sized mesh. That’s a handoff problem, not a reason to drop open-source CAD. Three checks fix it.
1. Export by object, not as one lump. In FreeCAD, select the objects you want (walls, slabs, openings) and export them as OBJ, giving each one a clear name first. When you import into Blender (File → Import → Wavefront OBJ), turn on Split by Object so every FreeCAD object stays its own Blender object and you can give each one its own material.
2. Get the units right. FreeCAD works in millimetres, and Blender’s default unit is the metre. So a 10 m wall arrives as 10,000 units, which is your city-sized mesh. Either set Scale to 0.001 in the OBJ import options, or set the scene to millimetres first (Scene Properties → Units: Unit Scale 0.001, Length = Millimeters). Then press N and check one known dimension before you go any further.
3. Fix the axes once. If the model arrives lying down, set the importer’s Up Axis to Z and Forward Axis to Y, which matches FreeCAD’s Z-up world, and re-import. Don’t rotate it by hand, because every re-export would need the same fix.
Then render. Select everything and press Ctrl+A → Scale, recalculate normals (Edit Mode, Shift+N), add your PBR materials, and set up the camera. Units and export order are the boring part, and they’re what makes the render easy.
The full FreeCAD-to-Blender workflow, from Arch walls to a lit Blender render, is in my course Architectural 3D Modeling & Rendering: FreeCAD & Blender.
