If you are using Solidworks (or maybe other 3D CAD) to generate the airfoils, the best way to do it is to use the 'Curve thru X,Y,Z Points". This allows you to import (from a website) the actual NACA airfoil coordinates and generate a 'Unit' sized airfoil. [ the airfoil will be 1 mm, or 1in, or 1 ft or...; depending on what your units are set to] Note that the airfoil data you import from a website will only contain 2 data sets, one for X dimension, and one for Y dimension, simply copy that data into Excel and add a third column for Z dimension (all zeros) to use in SW. This method will give you a curve that is a perfectly smooth, not facteted, airfoil. You then start a sketch on same plane as curve and then 'Convert' the curve into the current sketch which will give you a spline. If needed you can edit this spline, typically at the trailing edge, if needed. Then you can then create a surface or solid and scale that to reach the exact size airfoil you need for the different locations of your wing or prop. You can also save out the airfoil (preferably the 'unit' sized one) as a block and import it into other models. If you have to locate the airfoil on a plane other than the Main X,Y or Z planes you can use the 'Move' function to do so, usually before scaling. This method is how I do all my aircraft wings and airfoils and it produces perfect surfaces.