I think Kevin is not referring to pixels, but Voxels.
STL is triangulated geometry. The triangles describing curved surfaces are planar; where large enough, those planes can become visible in the print when using a printer with the resolution of the Form2.
MOST models you can download online will show planar geometry because they are modeled to render good, rather than be printed.
I routinely model at 80 million polygons- but because of preform’s 32 but memory limitations, I have to decimate the file down to under 140 mb or preform won’t input it.
It also has a bug importing several STL files in a row… claiming subsequent imports are “bad” geometry when I know they are perfect.
However- the problem with STEP or other formats that have spline surface capability is that surface modeling has real problems with solidity.
It doesn’t matter in MILLING because the mill software is only deriving a TOOL PATH in space… the cutting head doesn’t care which side of the surface is solid… it will trace the surface in free air if there is nothing to cut in its way.
But all Print technologies REQUIRE the model to qualify as a topological solid. The printer is not CUTTING a preexiuating material to form- it is deposting solid material where the model is solid… so the file need to know what parts of the model ( all the way thru ) are solid- not just the surface acutting head will trace.
STL- by eliminating all spline data- stitch data- and not having to deal with coons patches versus other types of UV geometry- has far less issues maintaining solidity, and is far easier to rectify lack of solidity.
Its no big issue to convert subD or surface data to STL- unless your software is not capable of resolving or detecting solidity issues.
Also- the idea that STEP files or IGES files are smaller is a myth.
They are generally much smaller when modeling simple shapes like engineered parts composed of cubes and cylinders… but to model a highly detailed organic figure in nurbs with any level of accuracy requires so many fit points per patch and so many patches that the file size quickly equals or exceed an STL model that can capture the same level of detail.
And the only way to reduce the file size of a surface model is to LOSE overall fine resolution- whereas STL models Can be intelligently decimated down to a target size and preserve fine details.
Used to be, we only ever created nurbs models because many milling apps would ONLY accept surface data… tho for 15 years now, most modern milling apps can mill directly from STL as well.
Parametrics and surface modelers are fine for engineering… but for anything organic, Voxel stl modelers and subD apps reign supreme.
And Preform accepts both STL and OBJ… so-
The last figure I did in nurbs ended up being a 1.2 GB STEP file… Preform can’t import that much data even if it could accept IGES or STEP.