Rotate 3-D Point Cloud Using Rigid Transformation
33 views (last 30 days)
Show older comments
Hi! I need to rotate a point cloud (or .txt file of the type rx3) by a certain angle theta with respect to the x-axis (or y- or z-axis) while keeping its center of gravity G (already calculated) fixed.
I am using the rotation matrix but I am unclear how to keep the center of gravity fixed and rotate only with respect to a given axis.
angle = 180;
angle_rad = deg2rad(angle);
rot_matrix = [ cos(angle_rad) sin(angle_rad) 0 0 ; ...
-sin(angle_rad) cos(angle_rad) 0 0 ; ...
0 0 1 0 ; ...
0 0 0 1 ];
I had initially tried using this code taken from this link but MatLab reports this error: "Unrecognized function or variable 'rigidtform3d'."
ptCloud = pcread('teapot.ply');
figure
pcshow(ptCloud)
xlabel('X')
ylabel('Y')
zlabel('Z')
rotationAngles = [0 0 45];
translation = [0 0 0];
tform = rigidtform3d(rotationAngles,translation)
ptCloudOut = pctransform(ptCloud,tform);
figure
pcshow(ptCloudOut)
xlabel('X')
ylabel('Y')
zlabel('Z')
Thanks to those who can answer me!
p.s. Otherwise if someone can send me this function ("rigidtform3d") since it's like I don't have it!
0 Comments
Accepted Answer
More Answers (2)
Bora Eryilmaz
on 20 Dec 2022
Edited: Bora Eryilmaz
on 20 Dec 2022
- First translate the point cloud to the origin using a translation of -G.
- Rotate the point cloud around an axis.
- Translate it back to its center of gravity using a translation of G.
0 Comments
Torsten
on 20 Dec 2022
Edited: Torsten
on 20 Dec 2022
angle = 180;
angle_rad = deg2rad(angle);
rot_matrix = [ cos(angle_rad) -sin(angle_rad) 0 ; ...
sin(angle_rad) cos(angle_rad) 0 ; ...
0 0 1 ];
ptCloud = pcread('teapot.ply')
gc = mean(ptCloud.Location,1)
figure
pcshow(ptCloud)
xlabel('X')
ylabel('Y')
zlabel('Z')
gc = mean(ptCloud.Location,1)
ptCloudOut = ptCloud.Location - gc;
ptCloudOut = (rot_matrix*ptCloudOut.').';
ptCloudOut = ptCloudOut + gc;
gc_transformed = mean(ptCloudOut,1)
figure
pcshow(ptCloudOut)
xlabel('X')
ylabel('Y')
zlabel('Z')
0 Comments
See Also
Categories
Find more on Point Cloud Processing in Help Center and File Exchange
Community Treasure Hunt
Find the treasures in MATLAB Central and discover how the community can help you!
Start Hunting!