Thanks for your file.
You shouldn't use Cycles materials, but simple materials with Diffuse and Specular colors like in the file attached to this post.
By the way, your objects are too detailed / heavy: with an OBJ file of 27 MB for a simple chair, you'll soon run out of resources in Sweet Home 3D.
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BlueBox.blend
(457452 bytes)
(Download count: 176)
(A Blender file showing a simple blue box)----------------------------------------
Emmanuel Puybaret, Sweet Home 3D creator
