Finding convex hull of an obj file

I need to compute the convex hull from an obj file. How would I go about doing this in Matlab? Ideally I just need the volume of the hull, or an obj output file.

I have been trying to use convhulln and OBJ=read_wobj, but I am new to Matlab, I don't know how to actually compute a convex hull from the points in the obj file.

[Image Analyst]

What is an obj file? MATLAB has several functions for convex hull like convhull(), convhulln() and bwconvhull().