#1
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positions on animation path
Hi, I would like to create an environment in which a ball is going around the original point. My simple code just create an animation path of a circle for a ball and try to figure out the actual positions when the ball pass along the animation path. My question is why the printed positions are not on a circle like what we can see? And so why the distance between the ball and the original point are not the constant value 10? Thanks!
Code:
import viz viz.go() import math viz.add('tut_ground.wrl') ball = viz.add('ball.wrl') viz.MainView.move([0,3,-20]) path = viz.addAnimationPath() positions = [ [0,1,10], [10,1,0], [0,1,-10], [-10,1,0], [0,1,10] ] for x in range(len(positions)): cp = viz.add(viz.CONTROL_POINT) cp.setPosition(positions[x]) path.add(cp,x+1) path.loop(viz.CIRCULAR) viz.CUBIC_BEZIER path.translatemode(viz.BEZIER) path.computetangents() path.setAutoRotate(viz.ON) mylink = viz.link(path,ball) path.play() def mytimer(num): pc = ball.getPosition() print 'position: ', pc dist = math.sqrt( (pc[0]-0.0)*(pc[0]-0.0) + (pc[2]-0.0)*(pc[2]-0.0) ) print 'distance: ', dist viz.callback(viz.TIMER_EVENT, mytimer) viz.starttimer(0,1/60.0,viz.FOREVER) |
#2
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You won't be able to create a perfect circle using bezier paths. You are better off manually animating the object. Either way, the following modified version of your script will generate a path that is closer to a circle. It uses cubic bezier and you removes the duplicate control point at the end of the path:
Code:
import viz import vizmat import vizact viz.go() viz.add('tut_ground.wrl') ball = viz.add('ball.wrl') viz.MainView.move([0,3,-20]) path = viz.addAnimationPath() positions = [ [0,1,10], [10,1,0], [0,1,-10], [-10,1,0] ] for x,pos in enumerate(positions): cp = viz.addControlPoint() cp.setPosition(pos) path.add(cp,x+1) path.loop(viz.CIRCULAR) path.translatemode(viz.CUBIC_BEZIER) path.computetangents() path.setAutoRotate(viz.ON) mylink = viz.link(path,ball) path.play() def PrintInfo(): pc = ball.getPosition() print 'position: ', pc dist = vizmat.Distance(pc,[0,1,0]) print 'distance: ', dist vizact.ontimer(0,PrintInfo) |
#3
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I'll try that. Thank you.
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#4
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Hi,
If I happen to create another non-circle path using bezier paths, would the distance we can see/feel in VR is close to the actual distance that calculated by vizmat.Distance(). Thanks! Quote:
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