[Bf-vfx] Plane Tracking naming

[Keir Mierle]

I am aware of this thread guys, and will comment in a day or so; currently
swamped on other fronts. The tracker DOES track a plane by solving for a
plane implied by 4 or more tracks.


On Mon, Aug 12, 2013 at 7:43 PM, Sean Kennedy <mack_dadd2 at hotmail.com>wrote:

> New tools put into the tomato branch last week by Keir and Sergey.
> The tool is called Plane Track. It's pretty awesome!
>
> Sebastian's quick demo
> https://vimeo.com/71727578
>
> Keir's more in-depth demo
> http://www.youtube.com/watch?v=vISEwqNHqe4
>
> ------------------------------
> From: davidj at gmail.com
> Date: Mon, 12 Aug 2013 19:33:09 -0700
>
> To: bf-vfx at blender.org
> Subject: Re: [Bf-vfx] Plane Tracking naming
>
> And no, corner pin simply implies a rectangular image is being deformed to
> fit into a defined rectangular patch that has been tracked into live
> footage using multiple tracks.
>
>
> Given that, what feature in blender are you asking to rename
> corner-pinning?
>
>
> The single track perspective stuff Blender is doing when you set a tracker
> to use Affine or Perspective is actually planar tracking as generally
> accepted by the vfx community. However, there is no way to actually *apply
> * that planar data as a corner pin on it's own. That planar tracking is
> happening ONLY for the purpose of locking the individual track to it's
> pattern better.
>
>
> Right, my limited understanding is that the current tracker can't
> constrain multiple tracks to a plane, so the closest you could get to a
> "corner-pinned rectangular image" is tracking 3-4 points, and then either
> mapping a 3d triangle to the 3 points, or a quad to the four points.
>
> If we could put one tracker into the shot, set it to Perspective, track a
> plane, and then use the new corner pin tools on THAT plane, *that* would
> be planar tracking as the vfx industry understands it.
>
>
> Except this isn't at all what you want to do, because you want the tracked
> plane to have it's error minimized over all perspective trackers on the
> plane.. not driven by a single-tracker's quasi-accurate perspective track.
>
>
> Yes, in Mocha, you don't place actual trackers, it recognizes the entire
> feature inside the mask you create. It works as you describe, ignoring
> sections that become obscured or move out of frame.
>
>
>
>  In the example in that video, they draw a big mask around the screen,
> track it, then set up a corner pin on it, which magically sticks to the
> "plane" it just tracked. You cannot do that in Blender currently. You would
> have to track each corner of the phone, then place your corner pin box on
> the plane defined by those tracks. That is corner pinning.
>
>
> ..which BTW, sounds really nice..
>
>
> And actually, Blender is sort of in-progress with actually being able to
> do exactly what Mocha does. The Ceres library is already integrated, and
> planar recognition is being used to make individual point tracks more
> accurate (that's the Affine and Perspective modes).
>
> Scroll down to the "Planar Tracking" section
> http://wiki.blender.org/index.php/Dev:Ref/Release_Notes/2.64/Motion_Tracker
>
> But planar tracking is NOT yet being used the way it is in Mocha, to
> define an actual plane which you can then use to attach images to. It's
> strictly being used for more accurate point tracks.
>
> When those tools do eventually work, those are the tools that should be
> called "planar". Pinning a plane to multiple point tracks is simple good
> corner pinning.
>
>
> What tools are being called planar now? I'm not aware of any. That blender
> demo video had some casual uses of the term "planar" but AFAIK there is no
> such named feature in Blender. Am I wrong about this? Or are you simply
> objecting to terminology used in a demo video?
>
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