open a 3D image in opencv

edit

Project: 3D Data Processing

Input: wrl file

Detailed Description: I have CASIA 3D face database (link). I want to manually mark the facial feature points like nose tip, eye centers, lip contour, et cetera.

Can anyone suggest a GUI so that if I place cursor on say nose, the GUI should show the x,y,z coordinates of the point; like what GIMP provides for 2D images.

How to load, save, manipulate the wrl 3D file data like what is done for 2D images - image operations in OpenCV (imread, imshow, imwrite, ....)? C/C++ platform is preferred.