node3d.visible(viz.OFF) Problem

[Sandro Holzer]

Hello

I have a small problems with the node3d.visible command.

if I have 2 bodies like in the following code, when I swith off the visibility of the first body, then the second body also disapears.
Is there a workaround?

Thank you

Sandro

body1 = viz.add('body1.obj')
body2 = body1.add('body2.obj')

body1.visible(viz.OFF)

[Jeff]

You can link an empty group node to your original parent object and then set the group node to be the parent of your child object. Then when you change the visibility of the original parent it won't affect the child. Here's an example.

import viz
viz.go()

box = viz.add('box.wrl',pos=[0,0,5])

#add empty group node and link it to the box
group = viz.addGroup()
link = viz.link(box,group)

#add the ball with the group node as parent
ball = viz.add('ball.wrl',parent=group,pos=[0,1,0])

#toggle box visibility
vizact.onkeydown(' ',box.visible,viz.TOGGLE)

#move box back and forth
moveback = vizact.goto(0,0,10,3)
moveforward = vizact.goto(0,0,5,3)
move = vizact.sequence([moveback,moveforward],viz.FOREVER) 
box.addAction(move)

[Sandro Holzer]

Thank You Jeff

I just have one more problem with this code.
In the line:

ball = viz.add('ball.wrl',parent=group,pos=[0,1,0])

the position of the ball is in world coordinates,
I would need to give this position in relation to the box.
In my real code, there are a lot of bodies, all connected in something like a chain.
So if I have to calculate all the initial positions in world coordinates it would be a lot of work.
With the line

body2 = body1.add('body2.obj')

in my original code all this work is done by Vizard. (but visibility does not work the way I want)

Do you have an idea how to do this?
Sandro

[Jeff]

the position of the ball is set in its parent coordinate system, the default is viz.ABS_PARENT. So the ball is always [0,1,0] in the group node's coordinate system which is the same as the box. If you try

print ball.getPosition(viz.ABS_GLOBAL)

you'll see its position is not [0,1,0] in the global coordinate system

[Sandro Holzer]

Hi

Sorry, I am not able to work it ou by myself.
I added a small sample, and it should work like this:
there are 3 bars in a chain. The bar-body is attached
bar1 should rotate araund the vertikal axis (keys "t" and "b")
on the end of bar1, bar2 is connected and should rotate like a arm.
and on the end of bar2, bar3 is connected and should also rotate like a arm.

and then I want to switch the visibility of bar2

The first code is like I want it:

import viz
viz.go()
 
viz.clearcolor(0.1,0.1,1)
#ground = viz.add('tut_ground.wrl')
ANCHOR_POS= (0.6,1.8005,6)
bar1 = viz.add('bar2.obj',pos=ANCHOR_POS)
bar2 = bar1.add('bar2.obj')
bar2.translate([0.0,0.0,-1])


bar3 = bar2.add('bar2.obj')
bar3.translate([0.0,0.0,-1])

a = 0
b = 0
c = 0

def mytimer(num):
	global a,b,c
	if viz.iskeydown('t'):
		a = a + 1
		if a > 89:
			a = 89
		
		move()
	if viz.iskeydown('b'):
		a = a - 1
		if a < -89:
			a = -89
		move()
		
	if viz.iskeydown('f'):
		b = b + 1
		if b > 89:
			b = 89
		move()
	if viz.iskeydown('h'):
		b = b - 1
		if b < -89:
			b = -89
		move()
		
	if viz.iskeydown('z'):
		c = c + 1
		if c > 89:
			c = 89
		move()
	if viz.iskeydown('n'):
		c = c - 1
		if c < -89:
			c = -89
		move()

def move():
	
	euler = bar1.getEuler(viz.ABS_GLOBAL)
	euler[0] = a
	bar1.setEuler(euler,viz.ABS_GLOBAL)
	
	euler = bar2.getEuler(viz.ABS_GLOBAL)
	euler[1] = b
	bar2.setEuler(euler,viz.ABS_GLOBAL)
	
	euler = bar3.getEuler(viz.ABS_GLOBAL)
	euler[1] = c
	bar3.setEuler(euler,viz.ABS_GLOBAL)


	
	
vizact.onkeydown(' ',bar2.visible,viz.TOGGLE)

viz.callback(viz.TIMER_EVENT,mytimer)
viz.starttimer(0,0.02,viz.FOREVER)

The following code is with the linked group:

First problem, the bar3 is not at the end of bar2 (you have to navigate back to look for it) this has something to do with the ANCHOR_POS of the first bar.
Second problem, bar3 follows bar2, but not the bar1.

import viz
viz.go()
 
viz.clearcolor(0.1,0.1,1)
#ground = viz.add('tut_ground.wrl')
ANCHOR_POS= (0.6,1.8005,6)
bar1 = viz.add('bar2.obj',pos=ANCHOR_POS)
bar2 = bar1.add('bar2.obj')
bar2.translate([0.0,0.0,-1])
group = viz.addGroup()
link = viz.link(bar2,group)


bar3 = viz.add('bar2.obj',parent=group,pos=[0.0,0.0,-1.0])



a = 0
b = 0
c = 0

def mytimer(num):
	global a,b,c
	if viz.iskeydown('t'):
		a = a + 1
		if a > 89:
			a = 89
		
		move()
	if viz.iskeydown('b'):
		a = a - 1
		if a < -89:
			a = -89
		move()
		
	if viz.iskeydown('f'):
		b = b + 1
		if b > 89:
			b = 89
		move()
	if viz.iskeydown('h'):
		b = b - 1
		if b < -89:
			b = -89
		move()
		
	if viz.iskeydown('z'):
		c = c + 1
		if c > 89:
			c = 89
		move()
	if viz.iskeydown('n'):
		c = c - 1
		if c < -89:
			c = -89
		move()

def move():
	
	euler = bar1.getEuler(viz.ABS_GLOBAL)
	euler[0] = a
	bar1.setEuler(euler,viz.ABS_GLOBAL)
	
	euler = bar2.getEuler(viz.ABS_GLOBAL)
	euler[1] = b
	bar2.setEuler(euler,viz.ABS_GLOBAL)
	
	euler = bar3.getEuler(viz.ABS_GLOBAL)
	euler[1] = c
	bar3.setEuler(euler,viz.ABS_GLOBAL)


	
	
vizact.onkeydown(' ',bar2.visible,viz.TOGGLE)

viz.callback(viz.TIMER_EVENT,mytimer)
viz.starttimer(0,0.02,viz.FOREVER)

[Jeff]

Here are two options. For your code without the group node you could replace

vizact.onkeydown(' ',bar2.visible,viz.TOGGLE)

with something like

vizact.onkeydown('1',bar2.disable,viz.RENDERING)
vizact.onkeydown('2',bar2.enable,viz.RENDERING)

the third bar will continue to be rendered whether or not the second one is

in the code with group node and the link you could add

link.setSrcFlag(viz.ABS_GLOBAL)

after creating the link. The third bar will be in the correct position and you can toggle the visibility of the second bar.

[Sandro Holzer]

Thank you Jeff

The version with "bar.disable,viz.RENDERING" works best for me, and I think this is the easiest way to do it.
And with this version I can still use the "box.visible,viz.TOGGLE" command when I want all linked nodes to disappear.

Sandro