hey everyone … what are hese dark spot and how do i get rid of them,
i did solve some problems by recalculating the normal outside,
a word about the mesh, it started as a curve, revolved to about 90degrees ,
then mirrored to become 180deg,
thank you 
Hello.
Try selecting all the verticies along the centerline of the mesh in Edit Mode and scale them down to 0 while holding the middle mouse button. Then hit the W key and choose Remove Doubles. Next select all verts and recalculate the normals with Ctrl + N.
It’s real easy to end up with extra verticies, edges, or objects if you’re not careful. Or to have two verticies which look like a single one until you zoom in on them (Alt + M = real helpful here). Inspect the mesh carefully for these things.
Good luck!
well i did it before and tried again when i saw your message, but no i have single vertices all along this line merged and all
this did not correct the prob,
but thank you for helping 
me appreciates the effort
-max
Hmm. Mind posting a .blend?
This has got me curious.
i’m sorry, but i don’t own these files, i am doing this for someone to whome i promised confidentiality, however, since it may be a silly mistake on my behalf, i decided to attach part of the file, i suppose it is safe to do this without compromising my word 
thank you for understanding, plz tell me how you fixed this so i can fix the rest…
-max
help.blend
Link don’t work.
%<
sorry
there is a permisssion issue
goto http://maxwildcat.50megs.com/my_blender/
click on help.blend to download
----FIXED
Sorry, the link still won’t work.
me fix, you try
lol
You’ve got extra faces and edges in the seam.
Go to Edit Mode, Hit Z for transparent faces.
Hit Nub-Pad 3 to go to “side view”. Center and zoom to see better.
Box Select (B key) the verts in the seam and middle-mouse+scale to 0 again. Remove doubles. (34) extra
Then got to Edge Select Mode (diagonal line on far right) and Shift + R-mouse select all extra edges in the seam. (visible at an angle) X key and Delete Edges.
thank you, that worked out well, turned out to be silly after all,
this project is going to autocad to the less edges the better i suppose
i’m sorry to ask this
but do you have a technique for the red component?
(i assume its the same prob there)…
max
never mind it was a simple vertex paint porblem,
thing is i had a third component with this prob, i looked for extra edges or faces and found none… i fixed it buy simply repainting the vertices…
when i reached the green component i tried to repaint vertices with no avail, when i got to the red part … i go t abit lost , thank you guys, blender(and python) ROCKS… you guys are the best 148 ppl read this post in less than 10hrs no other forum can claim that …
-max
Glad to help.
If you still notice any black areas, Look for any planes which come together as a T or H. I don’t know if these are a problem for Auto Cad but Blender prefers “L s”.
Anyway good luck with the job!