This is a beginners question…but,
how do i create a surface on my model (as shown in picture) in the area in the middle where its empty… I have tried to just draw lines between them but i keep getting triangles which in my opinion doesnt look so nice…Any tips from SketchUp pro’s out there?
You’ll probably need to triangulate this—Since it’s unlikely that the four corners fall upon the same plane. . . the three corners of a triangle always define a common plane, so it’s the go to technique when all else fails.
there could be a few different ways to triangulate here, so experiment some to get what you need.
the lighting is highlighting the plane changes here.
you could try changing the lighting direction around, or rotate the model so it catches the lighting differently.
OR, increase the amount of triangulation being used… subdividing the span into smaller faces will tend to diminish the angle of the plane change that’s happening.
OR… Don’t do any triangulation at all… Instead see if you can adjust the center pitch angle so that a four point plane will work.
allrigth! Thank you very much for the answers JimD! hero of the morning today! 
Don’t hide the edges of the triangles, soften them. Use the eraser+ctrl to soften them.
The two most likely reasons are,
the three edges don’t form a flat plane or
it’s too small to form a face.
But that is all we can guess from your screenshot.
Best bet is to start with a rectangle and draw your curve on it.
Start with a rectangle from the centre of the dome out to where the pipe finishes, draw the profile for half the dome then the path for the pipe. Eraser the bits you don’t need si you have a profile and a path. Add a circle at the centre point of the dome and at the end of the pipe. Then use follow me as appropriate.
I’m on my phone at the moment so you get a description rather than a demo.
Im not sure I understand what you mean @Box . To clearify; I want to make an object that looks like the concrete object in this picture…Maybe the previous image was a little unspecified…
Do you want to make the finished concrete form or the clever device used to shape it?
the finished concrete
Actually, no Dave I was buying a beer, but give me a sec.
Oops! I forgot it’s tomorrow. I’m just working on my third cup of coffee. 
I’m working on my hangover.
You must have a way to go. 
You might be surprised, I find really complex models on my computer that I have no recollection of drawing.
