WorldViz User Forum - Translate view from sensor position to lens position?

WorldViz User Forum (https://forum.worldviz.com/index.php)

- Vizard (https://forum.worldviz.com/forumdisplay.php?f=17)

- - Translate view from sensor position to lens position? (https://forum.worldviz.com/showthread.php?t=3583)

Translate view from sensor position to lens position?

Has anybody made a function to translate the viewpoint from the sensor position to the lens position on their hmd? I'm having a little trouble figuring out which method to use (preTrans, postTrans, or setOffset).

If your sensor contains both position and rotation data, then you need to apply a preTrans operator on the link to apply the offset between the physical sensor and actual eye position.

Example:

Code:

view_link = viz.link(sensor,viz.MainView)



# Physical sensor is 0.05 m above and 0.02 m behind actual eye position

view_link.preTrans([0.0,-0.05,0.02])

Yes sensor has both position and orientation (IS-900).

I am trying to run this on update so that I can use the euler information to determine which directions to apply the translation. When I use preTrans the view flies off in one direction.

I have tried subtracting the translation values from the preceding preTrans call, but that results in an accumulative translation error over time. I have also tried reseting each time before applying the preTrans. Both are commented out below. Thanks.

Code:

import viz

import viztask

import math



viz.go(viz.HMD | viz.STEREO)



isense = viz.add('intersense.dle')                

track = isense.addTracker()

main = viz.link(track,viz.MainView)



def mainLoop():

        yield viztask.waitKeyDown(' ')

        #Do Stuff



xOffOld=0.0

zOffOld=0.0

hmdLength = .29



def setViewTrackCorrection():

        global xOffOld,zOffOld

        #main.reset(viz.HEAD_POS)

        eul = main.getEuler()

        xOff = hmdLength*math.sin(math.radians(eul[0]))

        zOff = hmdLength*math.cos(math.radians(eul[0]))

        #main.postTrans([-xOffOld+xOff,0,-zOffOld+zOff])

        main.preTrans([xOff,0,zOff])

        xOffOld = xOff

        zOffOld = zOff



vizact.onupdate(1,setViewTrackCorrection)

viztask.schedule(mainLoop())

My mistake, I didn't realize preTrans was applied before rotation. Thanks for the help.

You should not call preTrans on every update. You only need to call it once when you initially setup the link.

Code:

import viz

import viztask



viz.go(viz.HMD | viz.STEREO)



isense = viz.add('intersense.dle')                

track = isense.addTracker()

main = viz.link(track,viz.MainView)

main.preTrans([xoff,yoff,zoff])



def mainLoop():

        yield viztask.waitKeyDown(' ')

        #Do Stuff



viztask.schedule(mainLoop())