slicing issues ( repetier/slic3r)

[chbeckdb9]

This is a repost from the machine specific page, the more I think about it, its a more general thing.
Been getting some good prints out of the rostock, but have had some issues with slicing. Sometimes when I import a .stl into the slicer built into the repetier, or even us Kiss slicer, the object will be tilted at a weird angle, or be below the print bed. What is happening ? Then when I try to manually correct it, and slice, it looks like a bunch of random plastic parts just floating in the air. I'm not printing anything too fancy, just prototype components to get a feel for how they will look, basically just a rectangle with holes, hollow, fillets etc.
Any suggestions?
Thanks!

[Polygonhell]

The geometry is probably bad.
I'd have to see an example STL file to be more specific, you can try running the models through netfabb, they have an online mesh fixing tool, but if you have as many problems as you are describing, it may not be enough. There is probably something you are doing in your modeling software of choice that causes the issue.

[DavidF]

Try slicing it in Cura, then save the gcode and load it into repetier. I have found that slic3r has some issuse with certain things. Make sure you run the first set up wizzard in cura.