We all know that S3D ignores walls smaller than the print width. Last night I printed a model with some walls equal to the print width. They printed, however, the extruder was making two passes on those walls I guess because I had shells set to 2. I would like to see S3D get smarter with these types of situations, since I need 2 shells for other parts of the model. Two processes might solve the problem, but I don't think it would be that difficult for S3D to handle this automatically.