Hello Baris,

I prefer to do some preplanning on the model and save my construction curve sets so if a filleting or blending operation fails I can back up and try another technique. The first issue I'd clean up is the large amount of control points you have on straight lines. I reworked your model and was able to get a consistent fillet on all surfaces if that is your objective. If you need different sizes of fillets on different areas you can also get there by doing your model planning and doing prefilleting on curve sets prior to extrusion and lofts.

Do you want to get a consistent fillet to break all of the sharp edges of the model? If so what are the desired parameters of the fillet? Unfortunately I'm out of space for attachments so I'd have to make a video to show the construction if that is OK.