make surface from points cloud

That's not really a CAD function. There are other programs that can do this, like PC-DMIS and Geomagic Raindrop.

Try looking up . Perhaps they can direct you to someone who performs this as a service.

I think it would be possible with SurfaceWorks (not sure, never used it)

You could try next one. Create 3D Sketch and sketch the points cloud to which you'll give the x,y,z coordinates. After doing that, "divide" the points into sections which you'll use to create 3D curves. Then create surface loft through those curves and use guide curves if necessary.

There's a problem.

These "scanned" files are created as if there were 3D solid pixels.

Consider a surface in a 3D grid of such pixels. IF any part of the surface passes thru a pixel that pixel is counted.

That means that any data point has an error added to it that's in the *3D* range of the pixel's dimensions, such as 1mm X 1mm X 2mm.

A smooth real surface will thus, if reconstructed from such data directly, have all sorts of complex surface features. And never can be considerd any better than the pixel size.

Sometimes, with very simple real surfaces, you *might* get lucky.