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Mixed reality – moving object, moving camera

by on Sep.14, 2009, under Augmented Reality

roomk asked:

Done some math to simulate correct rotation. Every complete rotation is a translation of 3.14 ball diameters on x axis… not so easy to implement. First test with full motion for object (rotation & translation) and camera. Some explanations (what follows is a replay to a comment/question by a youtube user, concerning tracking issues and ball movement): 1) About fiducial markers: some objects are always visible, for example the wall segment on the foreground; moreover, general geometry of …

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24 Comments for this entry

  • roomk

    thanks for your detailed comment!
    Render wasn’t the object of my experiment, I was interested in a good tracking and in the simulation (“mimic” is more appropriate) of the rotation of the ball. This is why I chose a stripped texture and a simple raytrace for the render ;-)

  • anim8ordude

    Track? Perfect.
    Render? Needs work. The lighting seemed unrealistic. Did you render it with a raytracing renderer? The lighting on the ball wasn’t bright enough and the shadows weren’t dark enough. Apart from that, fantastic job.

  • roomk

    …common logics?
    what’s that?

  • EntanglementSatan

    You did much math and stuff but you forgot the common logics! I mean.. you see there is a gap in between the two portions of the wall. Ball ought to fall there or ought to get disbalanced!!

  • roomk

    Yeah, that would be the mandatory next step :-)
    Thanks for commenting!

  • Kortail

    Nice, good work. Try and make a photorelistic renderning next time that would be awesome !

  • acroduster

    with a background in solid works and inventor, I would love to see open source solutions offered, but I think it will be some time, before we see the level of development currently in blender in any open source parametrically driven solid modeling. but I still hold hope.

  • roomk

    >maybee in time we will get to play with open >source engineering!

    yep, I hope so. ;)
    If only… in the meantime… I could find… an open source and free 3D CAD…with a satisfactory GUI on Windows… :(
    I’m in architecture…

  • acroduster

    no doubt! but thats why there are packages like pro e, kativ, solid works and inventor! with high end plug ins that can account for such variables. I doubt that hard core fluid mechanics will be included in blender or maya for that matter, any time soon. hel the plug in for full fluid dynamics in solid works is more than the core software right now. maybee in time we will get to play with open source engineering!)

  • roomk

    I mean, models are semplified pictures of phenomena, and each model is a “view” on a subset of them (otherwise we should simulate everytime the whole world… and then take a snapshot of the part we’re interested in).
    So I’m sure that guys at Oregon are using Blender for simple models not asking for accuracy in thermal issues.

  • roomk

    Well, it depends on the purpose of the simulation, I think.
    I’m pretty sure Blender can’t (yet…) consider variables such as, for example, temperature variation and consequent local density variation and convective effects on fluid motion… This is very difficult also at small scale, and virtually impossible at large (that’s why we can’t predict weather in medium-long term).

  • acroduster

    its interesting htat blender was the choice for one of the oceanagraphic departments at oregon state university for scientific evaluation of dynamic simulations, the physics engine and fluid sim features of blender are incredibly accurate to real work physics to the point that scientists are using blender for simulation evaluation. blender is not only great for art, but its parametric capabilities are very interesting for application other than art. but I know what you mean.)

  • roomk

    “[…]a project right now that just does not have the budget to justify its existence[…]”.
    That’s exactly what art is for ;-)
    Besides its technical implications, using Blender for dynamic simulations is always related to some form of art, I think (otherwise we should use more specialized software, in order to achieve “scientific” simulations).
    Never thought your comment was an attack.
    I appreciated it indeed. :)

  • acroduster

    dont sweat it! truth is, sometimes its just crazy the extra hours needed for something that seems so trivial! I am working on a project right now that just does not have the budget to justify its existence, but we are trying very hard to take the dynamic simulations to the max that blender can handle (we have plenty of computer power at our disposal) and we are dying trying to fine tune all the details! its brutal! I love your work though so dont think my comment was an attack.

  • roomk

    I should have used real rigid body simulation, or (less elegantly) manual animation to fake it…
    Next time!

  • acroduster

    only thing that dissapointed me was the lack of the ball dropping into the gap between concrete slabs. though I realize how much additional work that would entail!

  • firasnashed

    Very nice job – look at my movie Bisso Cat.

  • kusoheadexe

    okay…that really sounds like a lot to learn :P thanks anyway, i ve done similar thing before, just that i dont know how you can get shadow project on a real object in reality, and also make your object follow the track despiting the moving of the camera

    very cool indeed :)

  • roomk

    Fiducial markers are used to mark and identify points whose position in the scene you know exactly. They are used to help your pc in data analisys. Every persistent point in your footage can be a fiducial marker, if you say to your motion tracking software: “ehi! this point in frame #1 is this point in frame 16! keep this in mind!”.
    It’s better if you choose a lot of points (and every point far from the other), because a totally automatic recognition is a long process.

  • kusoheadexe

    ermm…so what’s a fiducial markers?
    is it to do with a third party software?

  • stokmarknes

    no, nothing is wrong with your vocabulary, but it’s to complicated for me when you start to explain in details:D

    THANK YOU for the short tutorial:D

  • roomk

    I’m sorry, don’t know.
    These are quite complex tasks, and you’ve to read many tutorials on every single task involved (camera/object animation, motion tracking, compositing, and so on).

  • roomk

    :( is something wrong with my vocabulary?

    1) make your ball rotate (you choose the speed) WITHOUT moving it.
    2) a complete rotation takes a certain amount of time. let’s suppose this time is 1 second.
    3) make your ball move along chosen axis, every 1 second, for a distance exactly [3,14 multiplied by (ball diameter)], that is circumference.

    In other words, every complete rotation, the ball runs a distance exactly equal to his circumference.

  • kusoheadexe

    is there any tutorial out there teach you how to do this?:)i mean with blender

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