and I tried use bezier curve to mesh to make a high poly round edge
but I just don’t know how to close the face and some place is still twisted
here is the blend file
thanks so much for any hint longboard4.blend.zip (1.41 MB)
You totally messed up with this curves and topology. If You’ll doing this more your computer will die before you finish this. I think You should start again from beginning. Start from simple cylinder for this long part (i have no idea what is name for it) then extrude the upper part, then slowly add details. Don’t apply subsurf modifier cause it’ll complicate everything and it’ll be difficult to edit it later. Work on lowpoly model and turn subsurf on only to check if everything is OK. This is my opinion. It’s hard to tell me anything from your file, cause this model is very unclear.
I have made very simple model of this part. I have no idea how it looks and as reference I was using your pic, so it probably not look like the real part, and still have lack of details, but I made it just to show You what i was talking about. I’m attaching .blend file and render. If You have any questions feel free to ask.