STL to STEP Lossless

[adilgamedev]

All what is needed to make the mesh 3d printable is that it is a solid.
Solid means that the mesh is watertight, i.e. it mustn't contain any triangles with an edge that has no adjacent triangle (boundary edges). Or in other words it mustn't contain any holes.

If your client insists on getting a STEP file then you should ask him why. The reason therefore cannot be that the object must be 3d printable.

I got this result when I tried to analyze an STP file I imported, everything is greyed out, and the model has a blue lining compared to when I once imported an OBJ in the past.

I know there aren't any holes due to using 3Ds Max to check manually and not finding holes.

In the end all I got was no holes, and "mesh" stp, which shouldn't be possible.

[mrdic]

The boundary surfaces of STEP solids can be composed of polygonal planar facets, that's not impossible. Enclosing a volume is what determines a CAD solid, not the types of surfaces that enclose it.

[adilgamedev]

Looks like I'll be doing what the previous comments said, ask the client why he specifically wants STP files if it's for 3D printing.