Turn off "Progressive" on Renderer sub menu (left Tab),and now you can see "Bucket size" menu appear on Sub menu off Optimization (Right Tab). Bucket size is similiar to Region Divison. I hope this can solve your problem. i'm sorry for my bad english...

looks cr@ppy- like a cg oilcloth. I suggest to download from vraymaterials.de some better alternatives (at least textures, since they are Max only), and watch zillions youtube material tutorials.

Thank you for your answer Jean. Infact i already work very organised. All the models i insert are already components. So copying instances is not a problem. Also no loose geometry or ungrouped objects. As i searched deeply, i found out that the main problem occurs when i export/import the models. The 550kb fireplace which i designed in 3ds max becomes 5mb when i export as fbx. And when i import it in sketchup via simlab's fbx importer it becomes 75mb... I have reported this to both autodesk and simlab. Waiting for an answer if there is an other way of exporting/importing without growing the file like this.