Stitching of surface bodies

[Geir.Olav.Guddal]

Hi,

I am working with a surface model which later will be used in a FEM analysis.

However I struggle with stitching the various surface bodies together and attach two simplified models to illustrate this:

The file "Two surface bodies stitching" works as intended and two surfaces are stitched together to a combined surface body:

The next file is a copy of the first one and there I make a third surface which I tries to stitch to the mentioned combined surface body. But the stitching fails:

Anyone who can explain me why this is not working and how to solve this problem? 

All advices related to surface modelling for later use in FEM is also highly appreciated.

[Scott_Parker · Accepted solution]

Stitching this would create Non-Manifold edges which Stitching doesn't support.  You could thicken these surfaces to create a single solid body.  Your FEM tool should be able to generate a midsurface for analysis from the resultant body.