3D Plot of cylinder with various radius changes

I have 3 columns of data (x,y,z)

This data makes up the points in space outlining a cylinder. as you go along the x axis the radius changes constantly (a few thousands or tenths of an inch) I have currently used plot3 and for the sake of making it easier I have assumed the diamter is constant.(it really changes with every x tick)

code: >> x=[0:120];theta=[0:30:3600];d=18; >> y=sin(theta)*d;z=cos(theta)*d;plot3(x,y,z)

However I need to be able to basically make up the "shell" of that data

Any ways to make this shell?