locate a certain point in the scene 3D

[farshizzo]

To find the intersect point you can also use the pick command.

info = viz.pick(1)
if info.intersected:
	print 'p1:',info.intersectPoint

Have you tried disabling lighting on the object?

object.disable(viz.LIGHTING)

This will prevent lighting calculations from being performed on the object, which will make it brighter.