I am using skeinforge to slice, and it doesn't have the option for "spiral vase". I wanted to edit the STLs so I can 3D print with regular settings using skeinforge. When I import the STL (hull bow for example) in Sketchup it will try to "fix" the file, and it imports with missing triangles, therefore the object has small holes. I think that is because the triangles are too small for Sketchup, because after it imports the STL I cannot manually fix the object, I have to increase the size by 1,000% to be able to manually fill in the missing triangles, but it's extremely time consuming!
Can you render the objects with lower resolution? (lower number of triangles?)