Your model is not a manifold solid. Change the way you view it to help yourself. View > Hidden Geometry > On - you'll see lots of stuff that was hidden or smoothed. That doesn't improve solidity tests. View Mode > MonoChrome to remove confusion of a textured surface. There are several 'flaps' and edges with only one face - every edge must have exactly one face. Manually fix these errors and the object should then report as a Solid in Entity info. To help identify the problem geometry I suggest you use Thomthom's SolidInspector2... and then doing a manual fix by editing it. Using a Style with distinctive profiles and endpoints might help. Also Xray mode would let you see what's a problem 'internally'... My Solidsolver fails to mend it at all. Fixit101 fixes somethings but then leaves it not solid ! PS: Delete the unwanted 'Sumele' figure as that doesn't help anything...