3d Surface from point cloud

Hi< I am new to Rhino. I have a surface point cloud data that I would like to build into a 3D model. I have been able to build a 3D box with the edges trimmed to match the surface cloud. All that remains is to get a renderred surface from the point cloud and then join to the box to make a full 3D model. I have tried to use Rhinoresurf to render the point cloud but the rendered surface is not joining with the box.
Can anyone please help me?

Assuming the “rendered surface” you are talking about is truly a NURBS surface, make sure it intersects completely with the box (by preference it should extend a little bit past the box in all directions). It should then be easy to split the box with the surface and split the surface with the box, then join the split surface to the split box and delete the extra unneeded parts.

If you are having trouble splitting either part, then it’s likely that you do not have a complete closed intersection between the surface and the box.