MATLAB: How to display the coordinate system of the figure (UCS icon)

coordinate systemdisplayimage processingucs icon

I have a 3D object having irregular shape and volume changing along the axes direction. I want to show the coordinate system icon in the figure associated with that object so that when I will rotate the object it will also change,like available in different CAD/CAE systems. How can I get this in MATLAB?

Best Answer

Hi yu, Yes I have done it a few times. You should be aware that this will work for me because the scale on each axis is equal. For example:
%before this you have plotted a surface in axis hAx
axis(hAx,'equal')
%Get X, Y and Z data for plotting the axes...
X_range = hAx.XLim(2) - hAx.XLim(1);
X_start = hAx.XLim(1);
X_delta = X_range/20;
Y_delta = (hAx.YLim(2) - hAx.YLim(1))/20;
Y_start = hAx.YLim(1);
Z_delta = (hAx.ZLim(2) - hAx.ZLim(1))/20;
Z_start = hAx.ZLim(1);
X_Line = line(hAx,[X_start+X_delta X_start+X_delta*5],[Y_start+Y_delta Y_start+Y_delta],[Z_start+Z_delta Z_start+Z_delta]); % x Line
Y_Line = line(hAx,[X_start+X_delta X_start+X_delta],[Y_start+Y_delta Y_start+Y_delta*5],[Z_start+Z_delta Z_start+Z_delta]); % Y Line
Z_Line = line(hAx,[X_start+X_delta X_start+X_delta],[Y_start+Y_delta Y_start+Y_delta],[Z_start+Z_delta Z_start+Z_delta*5]); %Z Line
X_text = text(hAx,X_start+X_delta*6,Y_start+Y_delta,Z_start+Z_delta,'x');
Y_text = text(hAx,X_start+X_delta,Y_start+Y_delta*6,Z_start+Z_delta,'y');
Z_text = text(hAx,X_start+X_delta,Y_start+Y_delta,Z_start+Z_delta*6,'z');
You can then play around with how long you want each line, the colors of the lines and text etc... I tend to use linkprop to link the properties of the lines that need to stay the same. If you do not have equal axis scales, this method wont really work...
Henry
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