Vizuniverse and grabhand

[initionSteve]

Hi,

Is there any documentation for how to use grabhand and vizuniverse? I've found two references that mention it in passing:
http://kb.worldviz.com/articles/1517
http://docs.worldviz.com/vizard/viztracker_setup.htm
and nothing else.

My task is to create a multi-user grabbing environment without using a cluster. I was hoping that I could use two grabhands on a single pc, with both a local sensor and a remote sensor running over VRPN. I would then sync the views on both the local and remote PCs.

Is there an example of how to add create multiple grabhands from multiple sensors in a single instance of vizard?

Thanks
Steve

[Gladsomebeast]

Hello Steve,

Here is an example showing how to create 2 GrabHand objects. You'll see from the GrabHand constructor, it has 2 dependencies:
-- a list of 3D nodes with physics shapes to grab
-- A hand object
---- Hand objects depend on having a InputSensor object that detects user input

The first half of the code sets up a local GrabHand controlled by the mouse. The second half is a code outline for setting up a remotely controlled hand.

import viz
viz.go()
viz.phys.enable() #must enable physics for grab to work
viz.add('lab.osgb')
viz.MainView.setPosition([0, 1.8, -2])

#objects to grab
grabObjects = []
for i in range(10):
box = viz.add('box.wrl', pos=[i/2.0, 1.7, i])
box.collideBox() #must have physics shape to grab
box.disable(viz.DYNAMICS) #no need for gravity
box.grabbed = 0
grabObjects.append(box)

#LOCAL HAND
#hand object that supplies user input: grabbing or not
import hand
mouseButtonControl = hand.MultiInputSensor(pinchButtons=[viz.MOUSEBUTTON_LEFT,viz.MOUSEBUTTON_RIGHT], fistButtons=[viz.MOUSEBUTTON_MIDDLE])
localHand = hand.add(mouseButtonControl)

#move hand position
import vizuniverse
handTracker = vizuniverse.VUTrackerMouse2D() #just a 3D node to supply position and orientation for hand.
viz.link(handTracker, localHand)

import GrabHand
GrabHand.GrabHand(grabObjects, localHand, springs=False) #springs only work on dynamics enabled physics shapes


#TODO FOR REMOTE HAND CONTROLLED VIA NETWORK
# Create local hand input object:
networkHandInput = hand.MultiInputSensor()
def onStartGrabFromNetworkEvent(): #called via network event callback, say viz.NETWORK_EVENT
networkHandInput.startPinch()
def onEndGrabFromNetworkEvent(): #called via network event callback, say viz.NETWORK_EVENT
networkHandInput.endPinch()

#create hand object
remoteHand = hand.add(networkHandInput)

# Get 3D position of remote hand
vrpn = viz.add('vrpn7.dle')
remoteHandTracker = vrpn.addTracker('Tracker0@localhost', 0)
viz.link(remoteHandTracker, remoteHand)

#create grabhand object
import GrabHand
GrabHand.GrabHand(grabObjects, remoteHand, springs=False) #springs only work on dynamics enabled physics shapes





WorldViz is still working to officially fold-in the two modules you mentioned so docs/examples are still sparse. Happy to provide more explanation if needed.

On the networking architecture side, I think your project is simple enough to just use a 'peer to peer' design where all clients hold the same representation of the world. The Tutorial:Networking in the Vizard help is an example of this. When world behavior is not deterministic, like with dynamic physics, then you should setup a client/server architecture. The viznet library in the install will help with this and I attached a zip with examples.

[initionSteve]

Thanks Paul,

That's exactly what I needed. I was planning to follow the tutorial for this, so it's good to get confirmation that it's a good idea. It's also good to know where I should shift to the more complex architecture.

Thanks once again,
Steve