where's the center

Hi,

I know this question I will ask is a dumb question for a guru in opengl but for me as a beginner in 3d, this question is so much helpful in my learning process.

Do you know where’s the center of a 3d object when you rotate it left, right up or down?

Rotation center is always at 0,0,0. So to rotate about a different center, you have to also apply a translation.

thanks for the reply.

I have another question.

Is nvsg also an opengl? Because i heard a group said that they were working with opengl but they’re using an nvsg sdk. Are they just the same?

NVscenegraph is an SDK that uses OpenGL under the hood and simplify scene management and bring a toolbox to simplify development, AFAIK.
http://developer.nvidia.com/object/scenix-home.html