Camera Problem with material

[AFK_Matrix]

I am redoing my 3rd year unit project and it has these curved tunnels. Now I am using Mental Ray and have just stuck a camera in and an MR area spot light just so I can quickly render the scene. Now in user view the bottom of the tunnel looks fine and renders fine. But when I view it through the camera I get these black streaks:

 

 

And when it renders it looks as though there is dirt on the material, I assume from these black marks.

 

What is causing this?

[Ricardo Eloy]

Looks like you have overlapping faces. Apply a shell modifier and it will probably work.

[AFK_Matrix]

Thanks for the tip but applying a shell modifier didn't seem to help. I can't see how its overlapping faces as all I have done is create a line for the arc and then lofted a half ellipse onto the line. And as I said it looks absolutely fine in User view.

[bijoy]

Holy crap...ive never seen overlapping faces do that anyway. those are more like streaks. try outlining(convert to editable spline->outline spline) ure arc first before lofting it. then check ure settings in loft and play around some of the settings in the skin parameters. check if u have enough faces/vertexes and so on. looks like it could be a graphics card issue though.

[alrawli]

What about another way of modelling it. Instead of loft ing the elipse along the spline you could try making the spline renderable and giving it a thickness then scaling it to make the cross section eliptical, then convert edital mesh/poly and add a shell.

[Ricardo Eloy]

Or you can try the sweep modifier, since you already have the path and the profile. Just make sure your profile is a closed spline.

[mdviz]

Have you checked that the mapping is ok? If you are getting a similar 'dirty' effect in the render too this suggests that the mapping needs looking at. Depending on your video card/drivers the accuracy of textures displayed in the viewports can vary.

Apply a simple checker material to help to identify if it is a mapping problem.