[Bf-vfx] Plane Tracking naming

[Ton Roosendaal]

Hi,

All feedback is welcome, but let's not make it too complex. We do have a procedure in place for how to solve issues like this.

Proposing naming of features is really a privilege of the developer first, but it should be agreed on by the module team (if there's a debate). If there's still no consensus we can ask related teams to decide (UI team) or the bf-admins in the end.

So - I suggest to have Keir and Sergey propose and Sebastian and Sean agree with it. If they are all happy discussion can be closed.

http://wiki.blender.org/index.php/Dev:Doc/Process/Module_Owners

-Ton-

--------------------------------------------------------
Ton Roosendaal  -  ton at blender.org   -   www.blender.org
Chairman Blender Foundation - Producer Blender Institute
Entrepotdok 57A  -  1018AD Amsterdam  -  The Netherlands



On 13 Aug, 2013, at 19:04, Sergey Sharybin wrote:

> 
> On Tue, Aug 13, 2013 at 9:34 PM, David Jeske <davidj at gmail.com> wrote:
> On Tue, Aug 13, 2013 at 12:36 AM, Sergey Sharybin <sergey.vfx at gmail.com> wrote:
> I do not happy with calling it "corner pin" because it's not  corner pin at all. You could (and probably even should) use more than 4 point tracks to make plane estimation much more accurate. Also, point tracks have no relation with corners at all: you could track points which are not corners of your plane (we showed this in our video).
> 
> The feature you are calling "plane track" appears *exactly* like corner pinning in Mocha and After Effects. The "corners" referred to in the name "corner track" or "corner perspective pin" are the corners of your "plane" not the trackers themselves.
> 
> http://www.youtube.com/watch?v=xRpHgVFPqqk&feature=player_detailpage&t=465
> http://www.youtube.com/watch?v=fY4wwZFD5-c
> 
> So is it a question like "let's call feature XXX exactly the same as it's called in software YYY"?
>  
> The reason it's not called planar-tracking is that it's not 3d, it's a 2d affine image transformation.
> 
> It's not affine, it's homography if it makes sense. 
> 
> Why do you call it a "plane"? As far as I can see, it's not a 3d-plane, but a 2d-affine compositing surface distorted in camera-space.
> 
> because it's a plane. You could think of it as a real non-concave plane being warped by a homography estimated from point tracks. Which is like if you watch on a viewplane on which that plane is being projected.
>  
>  
> Another usage of plane track might be constraining point tracks to belong to this plane while tracking them. Which means we might support other-way-around usecase: you create point tracks, you create plane out of them, and then starts tracking this point tracks taking plane constraint into account.
> 
> At that point, the track would be for a 3d-plane, and it would be appropriate to call it a planar-track.
> 
> That wouldn't be 3d, that'd still be based on homography estimation and making so tracks fits this homography in a best way (well, difficult to explain this in text, whiteboard would be much easier). At this point i couldn't see why or how we'll reconstruct 3D from point tacks in that case.
> 
> 
> 
> -- 
> With best regards, Sergey Sharybin
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