Hi,
I assume you are trying to recreate the Cad geometry in MATLAB .To make your bar graph look continuous, you can try to increase the width of bar to 1(default is 0.8) and put the EdgeColor to none to remove the black outline.
x=ones(10,10);
h=bar3(x,1);
for i=1:length(h)
set(h,'EdgeColor','none');
end
For example, considering a 10*10 matrix of ones, the above code gives the following output