Hi Jian,
I hope this snippet helps.
% Create two instances of a rigid body tree since we want two visuals
rbt=loadrobot("kinovagen3",DataFormat="row");
copyrbt=copy(rbt);
% Some random configurations
q0=homeConfiguration(rbt);
q1=randomConfiguration(rbt);
q2=randomConfiguration(rbt);
% Generate a trajectory to the random configurations
tpts=[0,1];
tquery=tpts(1):0.01:tpts(end);
traj1=quinticpolytraj([q0',q1'],tpts,tquery)';
traj2=quinticpolytraj([q0',q2'],tpts,tquery)';
% Find the patches which have a display name of '_mesh', and set their
% alpha values.
ax=show(rbt,traj1(1,:),PreservePlot=false,FastUpdate=true);
rbtpatches=findobj(ax.Children,'Type','patch','-regexp','DisplayName','_mesh');
set(rbtpatches,'FaceAlpha',0.2);
% Now visualize another instance of the same robot
hold on;
show(copyrbt,traj2(1,:),PreservePlot=false,FastUpdate=true,Parent=ax);
% This call will also find the previous patches. Hence we need to remove
% previously found patches from this query.
patchesnew=findobj(ax.Children,'Type','patch','-regexp','DisplayName','_mesh');
copyrbtpatches=patchesnew(~ismember(patchesnew,rbtpatches));
% You can also change the color aside from alpha
set(copyrbtpatches,'FaceAlpha',0.7);
set(copyrbtpatches,'FaceColor',[1,0,0]);
%% Visualize
rc=rateControl(50);
for i=1:size(tquery,2)
show(rbt,traj1(i,:),PreservePlot=false,FastUpdate=true);
show(copyrbt,traj2(i,:),PreservePlot=false,FastUpdate=true,Parent=ax);
waitfor(rc);
end
hold off;
Best,
Karsh
