Create Surface from Mesh?

BLOCK TOPS ONLY.3dm (719.2 KB)

Hi,

I am a rhino newbie, so please excuse the stupid questions.
I am using a 3D scan (has been created as a mesh), and am trying to convert it to a surface(?)
With the aim of creating a 3D printed mould. (will be used for plaster casting etc).

What is the best way to create a watertight surface/ object/ anything, that I can trim/ duplicate to create my mould?

I have been going round in circles trying to loft, join, create polysurfaces that won’t smooth.
I’m sure that there is probably an easier way to do this. But I am not knowledgeable in all the functions.

If anyone has any advice it will be greatly appreciated. Thank you.

Read this topic for answer :
https://discourse.mcneel.com/t/help-converting-a-mesh-to-nurbs/17329

The first step in converting a mesh to surface(s) is to think about the surface layout.

All surfaces in Rhino have four sides. It is possible for one, two, or even three sides of a surface to be zero length, but zero length sides should be avoided where possible.

Surfaces can also be trimmed. In general untrimmed surfaces, if possible, are preferable to trimmed surfaces but in many situations using one or more trimmed surfaces is appropriate.

Back to converting a mesh to surfaces. Look at the shape of the mesh and think about how it can be modeled using surfaces. Only start creating surfaces using the mesh after you have a plan for the surface arrangement.

Thank you both for the replies!