Weird layer

Can someone tell me what these weird steps are in my picture?  I greatly appreciate it.  


There appears to be a very slight incline on that inner face, probably due either to modelling weirdness or, more likely, the part being slightly off-square to the x-y plane.

The Cetus software could really do with a lie-this-facet-on-the-bed option.

Are you using Cetus Studio to slice/print? If so, did you have to level your print bed differently at multiple points? It looks to me like it's basically stair stepping the top layer.

If your bed is only a few tenths of a mm off, you're probably better off printing with a raft and letting the raft absorb the difference.

But if not, you should really level your bed hardware. I had a difference of about 0.4mm side to side and fixed it by shimming the build plate by loosening the screws, inserting a piece of paper on the side that was low and retightening the screws. 

I'd like to first thank you guys for your input but I figured out what the problem was.  When I exported from Autodesk I had to change the Brep to keep it from becoming a hexagon.  I first did High and that is actually what caused the printing issue. Went back an exported in Low resolution and now have a perfect print. I initially thought it was a slicer issue as my machine has been completely calibrated within the last week.  So if anyone is having problems with circular shapes and using Autodesk Inventor be sure to change the Brep options upon export. - Dave