Abstract: A rapid prototyping and manufacturing apparatus and method (e.g. stereolithographic apparatus and a method) for layer-by-layer formation of a three-dimensional object represented by cross-sectional data including a method and apparatus for deriving data for at least a portion of a region intermediate to two successive cross-sections of data for use in forming the three-dimensional object with improved surface resolution. Outward-facing regions on two or more successive cross-sectional layers of the object are compared to determine whether the outward-facing region(s) associated with one of the layers represents what was originally intended to be a smooth transitional region (i.e. a sloping region) between two cross-sections or a discontinuous region (i.e. vertical transitional region) between two cross-sections. The comparison may involve utilization of common boundaries between outward facing regions on the cross-sections.

Abstract: Oil based compositions are disclosed which are comprised of oil having a multi-functional additive component therein. The additive component is present in sufficient amounts so as to provide improved performance characteristics to the composition such as water tolerance and antiwear characteristics. The additive is a compound represented by the general structural formula (I): ##STR1## wherein R is a hydrocarbyl, preferably iso-stearyl, R.sub.1, R.sub.2, and R.sub.3 are independently hydrogen or alkyl, preferably hydrogen, n is 1 to 20, preferably 5, and X is a cation, preferably Ca. Overbased and mixed salts of the additive compound are also disclosed. The additive is an effective EP agent, water tolerance fix in a variety of functional fluids and lubricating compositions.