The opengl default reference (eye) coordinate system is: the origin is at the center of the window,Z-axis points out of the screen, X-axis points to the right,and Y is up. All coordinate transformation is based on this coordinate system. Is there any way to redefine this reference frame. Thank.

OpenGL coordinate system is right-handed by default and can’t be changed. Direct3D lets you choose right-handed or left-handed coordinate system.

… unless you multiply your modelviewmatrix to convert between coordinate systems.

M=[ 1 0 0 0

0 1 0 0

0 0 -1 0

0 0 0 1 ]

will invert the z-axis so the camera is *effectively* looking down the +Z axix.

cheers,

John