Hi guys, sr Im a newbie. I have been working on my 3D model and there is a thick, dark single line running across the surface of the object and u cannot click or move it. Can someone pls show me what is the name of the line and how to move it? Thanks in advance 
Hi Terry- most likely this is a seam either in a closed surface (like a sphere) or between two surfaces in a polysurface. Post a screen grab or the object in a 3dm file if you like.
-Pascal
this is the screen shot from my model. I want to move that dark center line but I dont know what it is and how to move it 
That looks like a seam between two surfaces I’d say . If so, you could ExtractSrf, ShrinkTrimmedSrf, and Untrim the surfaces, then MergeSrf with Smooth=No, and then retrim but I am not sure what the point would be… Why do you want to move that line?
-Pascal
because i wanna make a surface at the bottom curve but couldnt do it because of the seam
To me it looks like the seam of a single conical surface. You cannot get rid of it but you can move it. As Pascal says, extract, shrink, untrim. But then just rotate in the top view so that the seam lands in a different place - between two of the bottom cut-outs, I would say. Then trim the holes back in.
But you say that you couldn’t make a surface because of the seam. Your shape looks to be symmetrical. Can’t you copy the surfaces that you created on the other side and rotate these in position and join?
tks for the help guys, I was able to create surface using blendsrf later. And yes I just have to move the seam