Hi Kenia - I’d redraw the pebble shape as a clean single curvature continuous curve - the surfaces making up the basic shape are not very cleanly connected, especially the location you called out If you want a really smooth organic shape, there are better approaches, I’ll find or make an example file for you in a bit.
@kquintos13, here is a cleaned up version of your file - the surface is a loft between two curves that have identical simple, smooth structure - see how clean that fillet is? I also updated the file with a loose loft version that is more ‘organic’ , if that is what you are after. Again, curves are all the same, only edited for shape. I’ll attach another similar file that I made some time ago for a similar case.
Pebble_PG.3dm (234.2 KB)
Pebbly.3dm (88.9 KB)