Write a MATLAB script to create a 3D animation that features translation, scalin

Question

Write a MATLAB script to create a 3D animation that features translation, scaling, and rotation of an object created using the hgtransform() and makehgtform() commands

Explanation / Answer

% Visualize the quadcopter simulation as an animation of a 3D quadcopter. function h = visualize_test(data) % Create a figure with three parts. One part is for a 3D visualization, % and the other two are for running graphs of angular velocity and displacement. figure; mTextBox = uicontrol('style','text') set(mTextBox,'String','Press SPACE to continue') set(mTextBox,'Position',[170 170 200 20]) %plots = [subplot(3, 2, 1:4), subplot(3, 2, 5), subplot(3, 2, 6)]; plots =mTextBox; %subplot(plots(1)); pause; % Create the quadcopter object. Returns a handle to % the quadcopter itself as well as the thrust-display cylinders. [t thrusts] = quadcopter; % Set axis scale and labels. axis([-10 30 -20 20 5 15]); zlabel('Height'); title('Quadcopter Flight Simulation'); % Animate the quadcopter with data from the simulation. animate(data, t, thrusts, plots); end % Animate a quadcopter in flight, using data from the simulation. function animate(data, model, thrusts, plots) delete(plots); subplot(111); grid % Show frames from the animation. However, in the interest of speed, % skip some frames to make the animation more visually appealing. for t = 1:1:length(data.t) % The first, main part, is for the 3D visualization. % Compute translation to correct linear position coordinates. dx = data.x(:, t); move = makehgtform('translate', dx); % Compute rotation to correct angles. Then, turn this rotation % into a 4x4 matrix represting this affine transformation. angles = data.theta(:, t); rotate = rotation(angles); rotate = [rotate zeros(3, 1); zeros(1, 3) 1]; % Move the quadcopter to the right place, after putting it in the correct orientation. set(model,'Matrix', move * rotate); % Compute scaling for the thrust cylinders. The lengths should represent relative % strength of the thrust at each propeller, and this is just a heuristic that seems % to give a good visual indication of thrusts. scales = exp(data.input(:, t) / min(abs(data.input(:, t))) + 5) - exp(6) + 1.5; for i = 1:4 % Scale each cylinder. For negative scales, we need to flip the cylinder % using a rotation, because makehgtform does not understand negative scaling. s = scales(i); if s < 0 scalez = makehgtform('yrotate', pi) * makehgtform('scale', [1, 1, abs(s)]); elseif s > 0 scalez = makehgtform('scale', [1, 1, s]); end % Scale the cylinder as appropriate, then move it to % be at the same place as the quadcopter propeller. %set(thrusts(i), 'Matrix', move * rotate * scalez); set(thrusts(i), 'Matrix', move * rotate ); end % Update the drawing. xmin = data.x(1,t)-20; xmax = data.x(1,t)+20; ymin = data.x(2,t)-20; ymax = data.x(2,t)+20; zmin = data.x(3,t)-5; zmax = data.x(3,t)+5; axis([xmin xmax ymin ymax zmin zmax]); drawnow; % % Use the bottom two parts for angular velocity and displacement. % subplot(plots(2)); % multiplot(data, data.angvel, t); % xlabel('Time (s)'); % ylabel('Angular Velocity (rad/s)'); % title('Angular Velocity'); % subplot(plots(3)); % multiplot(data, data.theta, t); % xlabel('Time (s)'); % ylabel('Angular Displacement (rad)'); % title('Angular Displacement'); end end % Plot three components of a vector in RGB. function multiplot(data, values, ind) % Select the parts of the data to plot. times = data.t(:, 1:ind); values = values(:, 1:ind); % Plot in RGB, with different markers for different components. plot(times, values(1, :), 'r-', times, values(2, :), 'g.', times, values(3, :), 'b-.'); % Set axes to remain constant throughout plotting. xmin = min(data.t); xmax = max(data.t); ymin = 1.1 * min(min(values)); ymax = 1.1 * max(max(values))+0.001; axis([xmin xmax ymin ymax]); end % Draw a quadcopter. Return a handle to the quadcopter object % and an array of handles to the thrust display cylinders. % These will be transformed during the animation to display % relative thrust forces. function [h thrusts] = quadcopter() % Draw arms. h(1) = prism(-5, -0.25, -0.25, 10, 0.5, 0.5); h(2) = prism(-0.25, -5, -0.25, 0.5, 10, 0.5); %h(1) = prism(-sqrt(5)/2, -sqrt(5)/2, -0.25, 10, 0.5, 0.5); %h(2) = prism(-sqrt(5)/2, sqrt(5)/2, -0.25, 0.5, 10, 0.5); % Draw bulbs representing propellers at the end of each arm. [x y z] = sphere; x = 0.5 * x; y = 0.5 * y; z = 0.5 * z; h(3) = surf(x - 2*sqrt(2.5), y- 2*sqrt(2.5), z, 'EdgeColor', 'none', 'FaceColor', 'k'); h(4) = surf(x + 2*sqrt(2.5), y+2*sqrt(2.5), z, 'EdgeColor', 'none', 'FaceColor', 'k'); h(5) = surf(x-2*sqrt(2.5), y + 2*sqrt(2.5), z, 'EdgeColor', 'none', 'FaceColor', 'k'); h(6) = surf(x+2*sqrt(2.5), y - 2*sqrt(2.5), z, 'EdgeColor', 'none', 'FaceColor', 'k'); % Draw thrust cylinders. [x y z] = cylinder(0.1, 7); % thrusts(1) = surf(x, y + 5, z, 'EdgeColor', 'none', 'FaceColor', 'm'); % thrusts(2) = surf(x + 5, y, z, 'EdgeColor', 'none', 'FaceColor', 'y'); % thrusts(3) = surf(x, y - 5, z, 'EdgeColor', 'none', 'FaceColor', 'm'); % thrusts(4) = surf(x - 5, y, z, 'EdgeColor', 'none', 'FaceColor', 'y'); thrusts(1) = surf(x - 2*sqrt(2.5), y- 2*sqrt(2.5), z, 'EdgeColor', 'none', 'FaceColor', 'm'); thrusts(2) = surf(x + 2*sqrt(2.5), y+2*sqrt(2.5), z,'EdgeColor', 'none', 'FaceColor', 'y'); thrusts(3) = surf(x-2*sqrt(2.5), y + 2*sqrt(2.5), z,'EdgeColor', 'none', 'FaceColor', 'm'); thrusts(4) = surf(x+2*sqrt(2.5), y - 2*sqrt(2.5), z, 'EdgeColor', 'none', 'FaceColor', 'y'); % Create handles for each of the thrust cylinders. for i = 1:4 x = hgtransform; set(thrusts(i), 'Parent', x); thrusts(i) = x; end % Conjoin all quadcopter parts into one object. t = hgtransform; set(h, 'Parent', t); h = t; end % Draw a 3D prism at (x, y, z) with width w, % length l, and height h. Return a handle to % the prism object. function h = prism(x, y, z, w, l, h) [X Y Z] = prism_faces(x, y, z, w, l, h); faces(1, :) = [4 2 1 3]; faces(2, :) = [4 2 1 3] + 4; faces(3, :) = [4 2 6 8]; faces(4, :) = [4 2 6 8] - 1; faces(5, :) = [1 2 6 5]; faces(6, :) = [1 2 6 5] + 2; for i = 1:size(faces, 1) h(i) = fill3(X(faces(i, :)), Y(faces(i, :)), Z(faces(i, :)), 'c'); hold on; end % Conjoin all prism faces into one object. t = hgtransform; set(h, 'Parent', t); h = t; end % Compute the points on the edge of a prism at % location (x, y, z) with width w, length l, and height h. function [X Y Z] = prism_faces(x, y, z, w, l, h) X = [x x x x x+w x+w x+w x+w]; Y = [y y y+l y+l y y y+l y+l]; Z = [z z+h z z+h z z+h z z+h]; rot_mat = [cos(pi/4) -sin(pi/4); sin(pi/4) cos(pi/4) ]; for i = 1:length(X) vec=[X(i) Y(i)]'; vec_t=rot_mat*vec; X(i) = vec_t(1); Y(i) = vec_t(2); end end

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