The basic idea of animation of a rigid body motion is the same as that of animation of a moving point discussed in Section 2 and 3. The only difference is that in the case of a rigid body motion the object to draw and erase is a three-dimensional shape.
Let us make an animation of a moving block as an example. This can be done based on the script developed in Section 6 for drawing a block shape in a general configuration.
First, in order to make the script concise let us define a function that returns vertices and faces of a block shape as in Code 1.
function [vertices, faces] = calcBlock(r, R, Lx, Ly, Lz) % Return vertices and faces of a block geometry vertices_0 = [ 0, 0, 0; % #1 Lx, 0, 0; % #2 0, Ly, 0; % #3 0, 0, Lz; % #4 Lx, Ly, 0; % #5 0, Ly, Lz; % #6 Lx, 0, Lz; % #7 Lx, Ly, Lz]; % #8 vertices = r' + vertices_0*R'; faces = [ 1, 2, 5, 3; % #1 1, 3, 6, 4; % #2 1, 4, 7, 2; % #3 4, 7, 8, 6; % #4 2, 5, 8, 7; % #5 3, 6, 8, 5]; % #6 end
Using the calcBlock() function in Code 1, we can rewrite the script developed in Section 6 for drawing a block shape in a general configuration concisely as in Code 2 below.
% make_block.m
clear; close all;
% Reference position
r = [1; 1; 1];
% Reference orientation
R = eulerXYZ(-pi/3, 0, pi/6);
% Side lengths
Lx = 0.15;
Ly = 0.05;
Lz = 0.30;
% Vertices and faces
[vertices, faces] = calcBlock(r, R, Lx, Ly, Lz);
% Draw patch
figure(1);
h = patch('Faces', faces, 'Vertices', vertices, 'FaceColor', 'y');
% Axes settings
xlabel('x'); ylabel('y'); zlabel('z');
axis vis3d equal;
view([-37.5,30]);
camlight;
grid on;
xlim([0.8,1.3]);
ylim([0.9,1.4]);
zlim([0.8,1.3]);
