hideprecision 0=single precision 1 =double precision, can help if limes are missing.
Intersectiondisplay = show lines at intersection of 2 surfaces that would normally not show a line.
Intersectioncolor = Color of intersecting lines.
Dispsilh = show only the edges of a solid or surface and not all the triangles op polygons making up the surface.
Facetres = default is .5. lower makes surfaces with less polygons. works in conjuction with Viewres.
Viewres = control circle resolution
Layerevalcontrol = turn off reconcile layers
