Problem with <node3d>.center

[Jeff]

You can use the <node3D>.setPosition command to set the ball at ground level:

import viz
import vizact
viz.go()

ground = viz.addChild('tut_ground.wrl')
ball = viz.addChild('ball.wrl')
ball.setPosition([-2,0.5,7])
move = vizact.moveTo([2,0.5,7],speed=1)
vizact.onkeydown('1', ball.addAction, move)

[hachilab]

Thanks Jeff.
In fact the ground is not a flat surface. The level changes according to different positions.