I guess you are talking about this function: http://in.mathworks.com/matlabcentral/fileexchange/26160-carving-a-dinosaur?focused=6787518&tab=function
You are not providing all the inputs..you need to call the function like below:
xlim = [0 1] ;
ylim = [0 1] ;
zlim = [0 1] ;
N = 100 ;
voxels = findpeak(xlim,ylim,zlim,N) ;
You need to provide xlim, ylim, zlim which are 1x2 arrays and a number N.
