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Question: Calibration of size and speed of 3d objects

Discussion in 'AR/VR (XR) Discussion' started by carvinx, Apr 21, 2015.

  1. carvinx

    carvinx

    Joined:
    Mar 19, 2014
    Posts:
    34
    Hi, everyone

    I am just starting with a new project in VR and have some problems.

    I want to simulate a simple 3D-Ball like the real one in real world.

    I am using OptiTrack to register my camera( 3d glasses) and Middle VR(free edition) to realize the 3D effect in 3D room. And also Unity for 3D models and programming with C#.

    >> My Problem:

    I have a real plastic ball and use it to compare with that 3D-Ball. If i go to the real ball in (real world) it will be bigger and if i go away from it, it will be smaller visually.

    The 3d ball has the same diameter as the real one and stand at the same position. But if i go to ihm with 3d glasses it will be (quicker) bigger than the one in real world and if i go away from it, it will quick smaller than the real one...

    Can anyone explain to me, how to solve the problem, what should i do. I need your help.

    Thank you and have a nice day.

    Carvin.
     
  2. yuriythebest

    yuriythebest

    Joined:
    Nov 21, 2009
    Posts:
    1,121
    Hi! Haven't used VR&Unity yet, but this sounds like a convergence/separation/3d amount issue - try to mess around with those settings or similar settings
     
  3. carvinx

    carvinx

    Joined:
    Mar 19, 2014
    Posts:
    34
    Hi, Thanks for answer, but i am not sure what du really meant...can you explain more details to me? Thank you.
     
  4. 4ringz

    4ringz

    Joined:
    Apr 22, 2015
    Posts:
    13
    What scale are you using? Is your player a realistic height and moving at a realistic speed? What's your FOV? All these things will effect the impression of scale.
     
  5. carvinx

    carvinx

    Joined:
    Mar 19, 2014
    Posts:
    34
    Good morning, 4ringz

    thank you for your answer.

    I am using the World scale 0.5 of VRManager in Unity, so i understand so, that the world scale scales the movements of VR Nodes so scene appears smaller or bigger. But if i change it, nothing has changed for the size of the ball.

    The player is the 3d Glasses, i move with it in 3d room, and yes it has realistic speed, because i have tested the distance in Motive, and the value is right.

    For both of my 3d glasses i have set the FOV 50, but if i change it after running my program in Unity, nothing changed ...


    I just dont know why, and where should i change...thank you.

    Carvin
     
    Last edited: Apr 23, 2015
  6. OpticalOverride

    OpticalOverride

    Joined:
    Jan 13, 2013
    Posts:
    161
    Do you have anything else in your virtual room to compare to? Make sure the scale of entire simulation is correct.

    To me, it sounds like your virtual camera's movement is scaled improperly (when your head moves 1 meter in the real world, the virtual camera is moving > 1 meter for example). This would give the effect that you were describing; "If i go to the real ball in (real world) it will be bigger and if i go away from it, it will be smaller visually."

    In short, the head tracking software you're using is scaled improperly with Unity. Generally, 1 'unit' in Unity is equal to 1 meter (so a cube with a scale of 1,1,1 is 1 meter^3). Make sure to check out what scale OptiTrack is measuring your head movements (what the numbers OptiTrack is handing out really mean), and then do a little math in Unity to adjust.

    When working with VR, it helps to remind yourself that nothing in the physical world has a real "size" without comparing it to another object. They're all just objects with no size until compared. A galaxy can be massive when compared to a planet, or tiny when compared to the universe, etc. The scale of each measurable object (this includes the scale of head movements) is very important in VR because of this fact.

    Hope this helps!
     
    carvinx likes this.
  7. carvinx

    carvinx

    Joined:
    Mar 19, 2014
    Posts:
    34
    Hi, AnimalMother

    Thank you for your answer.

    I have a real ball with 4.5cm diameter to compare and i have also measured the distance (in real world) from A to B for my 3d glass with a ruler.

    For example in real world A moved to B: 1 meter, and i checked die 3d positions of my glass in the program OptiTrack Motive, and it showed me also 1 meter.

    But i will check out the scale like you suggested and give my feedbacks again.

    have a nice day.

    Carvin