Converting Cell Array into Array

I have 4 matrices with fixed columns but different rows (4 * n-by-3) created inside a for loop. I am storing them in a cell array but I cant convert it into array using "cell2mat" function. Is there way to convert the cell array or a better way to store the results may be without any cell to array conversion? Thanks for the help.

for i=1:4
  % Some calculations here
  rSet = ...    
  C{i,1} = {rSet};
end
cell2mat(C);
% Error using cell2mat (line 52)
% CELL2MAT does not support cell arrays containing cell arrays or objects.

Answer 1

[madhan ravi]

C=cell(1,4); % Preallocate before loop
C{i}...
% ^-—- is enough
vertcat(C{:}) %outside loop% or
[C{:}]

Answer 2

[Stephen23]

for i=1:4
  % Some calculations here
  rSet = ...    
  C{i,1} = rSet;
end
vertcat(C{:})

[MByk]

Thank you both.