asymmetrical rendering - help wanted!!

I created an Object with symmetrical modelling. No matter wich method i use (alt-d and mirroring, shift-d and mirroring, alt-d and scale on x-axis…), the rendered object is asymmetrical! the two halfes of the object have different shapes. In the editor it appears totally symmetrical!
Joining the two halfes doesn’t help.

Thanks in advance for your help!

Maybe the normals on the mirrored object point in another direction than the normals of the original object.
Go into edit mode, select all vertices and press Ctrl + N.

If this does not work I cannot help you. Everytime I used symmetrical modelling it worked without any problems.

Maybe this is problem with camera perspective? Try to set 200 mm for camera lens.

Thanks for the fast replies!
Recalculating the normals doesn’t work and i also tried different camera-perspectives and -settings.
Its veeeery strange, because this never happened before!

Can you show us a screenshot/render, or upload the .blend somewhere?

Here is the really ugly Pic. of my render. (should be something like a old armchair).
I think it’s some kind of normal-problem. The two halfes are shaded differently in the shaded mode, but the Normals are pointing in the same direction (in edit-mode). I also tried the “Double Sided”- and the “No V.Normal Flip”-Buttons.

I found out that i can fix the problem after joining the two halfes, but so i can’t continue with symmetrical modelling. javascript:emoticon(’%|’)

Get into the Front View (NumPad 1)
Select all vertices on only the “cut edge” or “seam”
Align them perfectly by pressing the S-Key and the X-key

Now copy the “good half” (all of the vertices) in edit mode with Shift+D . Press G-Key and X-Key and slide that half aside.

Press M-Key to mirror it

Press G-Key and X-Key to slide it back to the matching half of the chair.
Get it very close. Zoom in a few times to get it perfect.

Deselect all vertices.

Select the vertices in the joining (seam) area only and remove the doubles.

Finally correct the Norms and set the smoothing, if needed.