CAD design saved or exported as an .stl file is oriented on 3D Sprint build file preparation software.
Orientation or positioning the part to build in the SLA system is independent of the CAD location or orientation. File positioning in the SLA system should be dependent on the feature and/or function of the part. Flat planar surfaces are best when positioned horizontally as up-facing or down-facing surfaces. Cylindrical features such as holes or bosses should be built in a vertical orientation to better define the shape. Tapered parts, such as airfoils that transition with thick sections to a trailing edge, should be positioned with the thin edge oriented vertically to aid in the draining of resin.
However, don’t be afraid to be creative, since most epoxy resins are strong enough to build on an angle. This may also significantly reduce the amount of supports. A 45 degree angle is the most desirable because it has an equal pitch (the run is equal to the rise). Building on 45 degree angle can also optimize a part that has cylindrical features in several planar orientations. Avoid shallow angles if possible, since as the angle decreases, the steps become wider as each layer builds.