Do you mean two different .fig files?
You can generally find objects that live in an axes with findobj, which is good for looking for an object of a specific type. You can reparent those objects by setting the Parent (e.g. to a new axes, or from one old axes into another):L
This bit creates a couple of example surfaces
z1=peaks;
z2=z1+randn(size(z1))/5;
figure(1)
surf(z1)
savefig('foo1.fig')
figure(2)
surf(z2,'FaceColor','r')
savefig('foo2.fig')
The bit below opens the figures
f1 = openfig('foo1.fig');
f2 = openfig('foo2.fig');
The final section finds the surfc and copies them into a new axes:
s1 = findobj(f1,'Type','surf');
s2 = findobj(f2,'Type','surf');
figure;
ax=axes; % the new target for the old surfs
copyobj(s1, ax) % or s1.Parent = ax; to move it
copyobj(s2, ax); % or s2.Parent = ax; to move it
% note that the new axes won't inherit the configuration of the old axes
% (e.g. the 3-d view), but see below for an alternative.
view(3)
% or: just do copyobj(s1,s1.Parent) or s2.Parent=s1.Parent if
% you want to copy/move the second surface into the same axes
% as the first, preserving the view and other axes characteristics
