MATLAB code to get SLICE profile

 The below code is written in MATLAB it gives the coordinates when any object in an STL file is sliced at a desired height.

Input: STL file.

Output: Slice profile at a given height.  

clc;
clear all;
FV = stlread('A3.stl');  %d the stl file 
[F,V,N]=stlread('A3.stl');  %d Reading Stl file
sz= F.Points;   %d Reading the cordinates 

ma= max(sz(:,3));
mi= min(sz(:,3));

disp('Z must be between');
disp(ma); disp('and') ;disp(mi);



z= input('Enter Z height:');
km= F.ConnectivityList;
l=size(km);
i=l(1);
ka=1;

for j=1:i
    
    p=km(j,1); q=km(j,2); r=km(j,3);
    k1=sz(p,3); k2=sz(q,3); k3=sz(r,3);
    g1= max([k1,k2,k3]);
     g2= min([k1,k2,k3]);

            if ((g2<=z) & (z<=g1))
                
                  
                       if  ((sz(p,3)<=z) & (z<=sz(q,3)) | ((sz(q,3)<=z) & (z<=sz(p,3))))
                           
                             m= ((z-sz(p,3))/((sz(q,3)-sz(p,3))));
                             x(ka)=((m*((sz(q,1)-(sz(p,1)))))+(sz(p,1)));
                             y(ka)=((m*((sz(q,2)-(sz(p,2)))))+(sz(p,2)));
                             
                           ka=ka+1;
                       end 
                       
                       if  ((sz(p,3)<=z) & (z<=sz(r,3)) | ((sz(r,3)<=z) & (z<=sz(p,3))))
                           
                             m= ((z-sz(p,3))/((sz(r,3)-sz(p,3))));
                             x(ka)=((m*((sz(r,1)-(sz(p,1)))))+(sz(p,1)));
                             y(ka)=((m*((sz(r,2)-(sz(p,2)))))+(sz(p,2)));
                             
                           ka=ka+1;
                       end 
                       
                       if  ((sz(q,3)<=z) & (z<=sz(r,3)) | ((sz(r,3)<=z) & (z<=sz(q,3))))
                           
                             m= ((z-sz(q,3))/((sz(r,3)-sz(q,3))));
                             x(ka)=((m*((sz(r,1)-(sz(q,1)))))+(sz(q,1)));
                             y(ka)=((m*((sz(r,2)-(sz(q,2)))))+(sz(q,2)));
                             
                           ka=ka+1;
                       end 
                
            end


j=j+1;
end
plot(x,y);