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I am attaching a picture of what this looks like, this is actually a mild case where it's just an "ring" around the actual part. in some other prints, I have had larger unwanted sections of gcode that translated into parts that does not match the original STL. Any ideas why it's doing this? I'm using Repetier Host 0.85b which has slic3r 0.9.9.

No software is perfect, I'd try slicing the same object with KISS or Cura. The other possibility is that the model has a flaw in it somewhere. You can use a program like netfabb to check and repair objects. There's also a google sketchup plugin that does this, but I haven't played with it yet.

I've had problems like that with models out of OpenScad where two different shapes are suppose to fit seamlessly together but when it gets sliced, it'll make a lot of artifacts. I can sometimes fix the problem by slightly overlapping the two object by a tiny amount that isn't really visible to the eye.

yea, I've tried kisslice, and it works better, but I just like the object placement window on slicer better. The problem is really random, and not from the STLs which are generated with solidworks 2013. (i've put them thru netfab and it still generates the same thing. Here's another picture of a very similar print, but very apparent "abnormalities"

ichiban wrote:yea, I've tried kisslice, and it works better, but I just like the object placement window on slicer better. The problem is really random, and not from the STLs which are generated with solidworks 2013. (i've put them thru netfab and it still generates the same thing. Here's another picture of a very similar print, but very apparent "abnormalities"

When you load the STL in netfab, does it show any issues?
When you load it into kisslicer does it highlight any areas of the model?

It could be overlapping geometry, but without seeing the STL file that is causing the issue it's going to be hard to diagnose.
Slicers expect perfectly formed models and can do very strange things if the model is not "correct", overlapped geometry, degenerate faces, flipped normals can all cause issues.
Depending on the slicer the issues tend to vary.

If you are seeing issues with multiple slicers that do not share code say Slic3r and KisSlicer, then the problem is most likely in the model itself.

Here's part of the stl. kisslice generates the gcode without a hitch, and in kisslice, there is a small warning, but nothing major. I haven't done netfab on this particular one, but I generally never had any luck getting better gcode from slic3r after repairing the stl with netfab so i stopped doing it.