how to fill a surface to obtain a 3D mask

I have a script that gives me 3D coordinates of the surface of a 3D object.

I would like to obtain a mask in 3D where everything on and inside the surface is true, and everthing outside the surface is false.

The mask could for example be of size 64-by-64-by-64.

Roughly speaking a 3D version of imfill() that tolerates not all points being connected once they are placed in the mask grid.

Answer 1

[Image Analyst]

Is there any problem with just doing it one slice at a time using imfill()?

[Mads]

When for a given slice the points are connected, there is no problem. But when the curve is not closed imfill() doesn't work. I have tried imdilate() followed by imerode() to "invent" the missing points, but the operations seem to be a bit too harsh on the other parts of the curve. I wonder if there is some interpolation method that can fill out missing portions of the curve to close it...