Camera Zoom in GL Viewer

Hello ROOTers,

Could anyone tell me how to "zoom" geometries in the GL view? The ROOT users guide says that j/k keys works as zoom in and out. But its behavior is very similar to "Dolly" explained in the text. Because I can "enter" the O rings of $ROOTSYS/tutorials/geom/rootgeom.C by using only "Zoom" and "Truck" (see the attached). I think the zoom functionality should not allow the camera to enter the O ring.

Regards,

--
OKUMURA, Akira oxon@{astro.isas.jaxa.jp,stanford.edu}
Institute of Space and Astronautical Science (ISAS/JAXA)
Now at KIPAC/SLAC/Stanford
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