We can project points to a plane with cv.projectpoints and camera parameters. I want to get the new points coordinates with the camera parameters. And my problem is how to get projected points in 3 dimensions with the same xy coordinates as it in cv2.projectpoints.

we need more info to help, code, where do your points / matrices come from, etc

why do you expect the same xy in 3d ?

Sorry.

Now, I have smpl vertices, which are from a human model, and camera parameters. And I want to render human mesh matching the original image. So I need to project the smpl points to the camera coordinates. cv2.projectpoints works well in 2 dimension, so I want to get the 3d points with the same xy coordinates as it in cv2.projectpoints.