hgtransform

Rotate a group of objects around the z-axis. Create a 3-D star composed of Surface objects. Then, group the objects by parenting them to a Transform object, and apply the transformation to all the objects together.

Start by creating the axes and adjusting the view. Display grid lines and label the axes.

ax = axes("XLim",[-1.5 1.5],"YLim",[-1.5 1.5],"ZLim",[-1.5 1.5]);
view(3)
grid on
xlabel(ax,"x-axis");
ylabel(ax,"y-axis");
zlabel(ax,"z-axis");

Plot a 3-D star composed of multiple Surface objects. Because the surfaces represent a single shape, store them in an array, s.

[x,y,z] = cylinder([0.2 0]);
s(1) = surface(x,y,z,FaceColor="red");
s(2) = surface(x,y,-z,FaceColor="green");
s(3) = surface(z,x,y,FaceColor="blue");
s(4) = surface(-z,x,y,FaceColor="cyan");
s(5) = surface(y,z,x,FaceColor="magenta");
s(6) = surface(y,-z,x,FaceColor="yellow");

To group the graphics objects for transformation, create a Transform object and parent the Surface objects to it.

h = hgtransform;
set(s,"Parent",h)

Create a rotation matrix to rotate the group of surfaces pi radians around the z-axis. Then, apply the rotation matrix by setting the Matrix property of the Transform object h. The surfaces parented to h rotate pi radians around the z-axis.

R = makehgtform("zrotate",pi);
h.Matrix = R;

You can transform different objects within the same axes independently.

Start by creating the axes and adjusting the view. Display grid lines and label the axes.

ax = axes("XLim",[-3 1],"YLim",[-3 1],"ZLim",[-3 1]);
view(3)
grid on
xlabel(ax,"x-axis");
ylabel(ax,"y-axis");
zlabel(ax,"z-axis");

Create two spheres.

[x,y,z] = sphere;
s1 = surface(x,y,z);
s2 = surface(x,y,z);

Create two Transform objects in the specified axes.

h1 = hgtransform(ax);
h2 = hgtransform(ax);

Parent one sphere to h1, and parent the other sphere to h2.

s1.Parent = h1;
s2.Parent = h2;

Create a translation matrix to translate the second sphere away from the first sphere. Then, apply the translation matrix by setting the Matrix property of the Transform object h2.

Txy = makehgtform("translate",[-1.5 -1.5 0]);
h2.Matrix = Txy;

Animate a scaling and rotation transformation.Create a combined transform matrix composed of a scaling matrix that scales an object by 2 and a rotation matrix that rotates the object around the z-axis. Apply the transformation to the object, and display the animated effect of the scaling and rotation by incrementing the scale factor and angle of rotation in a loop.

Start by creating the axes and adjusting the view. Display grid lines and label the axes.

ax = axes("XLim",[-2 2],"YLim",[-2 2],"ZLim",[-2 2]);
view(3)
grid on
xlabel(ax,"x-axis");
ylabel(ax,"y-axis");
zlabel(ax,"z-axis");

Plot a 3-D star composed of multiple Surface objects. Because the surfaces represent a single shape, store them in a single array, s.

[x,y,z] = cylinder([0.2 0]);
s(1) = surface(x,y,z,FaceColor="red");
s(2) = surface(x,y,-z,FaceColor="green");
s(3) = surface(z,x,y,FaceColor="blue");
s(4) = surface(-z,x,y,FaceColor="cyan");
s(5) = surface(y,z,x,FaceColor="magenta");
s(6) = surface(y,-z,x,FaceColor="yellow");

To group the graphics objects for transformation, create a Transform object and parent the Surface objects to it.

h = hgtransform;
set(s,"Parent",h)

Create an animation that scales and rotates the group of surfaces at the same time. Define the scaling and rotation matrices, and multiply them to apply both transformations at the same time. Set the Matrix property of the transform to this combined transform matrix, and draw the 3-D star at each iteration of the loop.

for r = 1:.1:pi
    Rz = makehgtform("zrotate",r);
    Sxy = makehgtform("scale",r/2);
    h.Matrix = Rz*Sxy;
    drawnow
    pause(0.1)
end