[vtkusers] 3D coordinate

[Chandna, Sandeep (Research, Non-ge)]

Hi,
	I am using GetZ function defined in vtkRenderer to get the 3D coordinate , given an x/y pair. I have a volume and an axes (vtkAxes) in the display window.

The problem is that when I give the x/y location corresponding to the displayed axes, I get a correct Z value (corresponding to the axes 3D coordinate at that x/y location) , but if I give the x/y location of any other point (in the volume and not on axes) I get a Z value of 1 always. I am not sure where the problem is. Same problem comes if I use the GetZBufferData function defined in vtkRenderWindow.

Could some one throw some light on this.

Thanx
Sandeep