How do you place off-plane tracking markers on totally flat ground?

[hiphopcr]

Put a tennis ball on a poll and stick the pole in the ground

[jasonsco]

Tennis balls are pretty standard. I've even strung wire from floor to ceiling with tennis balls along it, spaced apart every few feet. Obviously, the nice thing about tennis balls is that they can be keyed out since they're a pretty good shade of green.

[GallenWolf]

Hi mates! Ok - tennis balls on poles/wires - great idea! I'll do a bit of testing to see what comes out. Thanks!

Alvin

[GallenWolf]

Hi, what if the ground is concrete? Any recommended way to place off plane markers in this situation?

[NickJushchyshyn]

Mic stands, lighting tripods, c-stands all work well.

Best to place ball markers or flat, cornered markers on these so there are explicit points to track.

[MasterZap]

What kind of camera move is it?

I never got good result with the Max tracker.

Try the free VooDoo camera tracker (google for it) instead, or try to find Icarus

/Z

[GallenWolf]

Nick - thanks! Was hoping for something more budget/diy though ;)

Master Zap: I'm planning for a free camera move. Oddly, I get very usable results from max's built in tracker... Voodoo, I can't get the ground plane to align correctly. Any tips? It works great, just that the axis are all crazy once imported.

Thanks!

[MasterZap]

Master Zap: I'm planning for a free camera move. Oddly, I get very usable results from max's built in tracker...

Well probably I never had good enough measurements (mostly guesstimates) when I used it.

It drives me nutty it doesn't even have a pan/zoom/tilt mode, which would need no measurements... heck you could have an "unshake" mode which simply takes ONE point, but no, you are FORCED to do the full 3d track every time.. and if your measurements are off... bye bye babye bye bye....


Voodoo, I can't get the ground plane to align correctly. Any tips? It works great, just that the axis are all crazy once imported.


Parent the imported camera (and trarget, if any) to a dummy, rotate/scale this dummy to fix any "wierdness of alignment".

/Z

[NickJushchyshyn]

Nick - thanks! Was hoping for something more budget/diy though ;)
Get some free weights (like for a bar-bell) from a sports shop (or perhaps a friend's basement)
Get some PVC to match the inner diameter of the holes in the weights.
Paint the PVC to taste and place it into a couple of stacked weights on the ground.
Have fun.

[GallenWolf]

Hi mates, sorry for the late reply kinda got caught up uv-unwrapping my current project :rolleyes:

Master Zap - I'm not sure what is a pan/tilt/zoom or unshake node - could you explain it? Or is it something that 3rd party trackers like boujou do best? You aren't refering to the corner pinning function right?

Anyways, this is one of the methods I setup for camera tracking. This is for small areas, using 3cm dots in a 30cm grid. I track the dots individually, then just run the camera match. Usually there will be some cleanup with the low pass or straight filter on the camera.

http://www.wired-wolf.com/alvinvfx/downloads/dfnStill.jpg

Ah, will try the axis alignment tip. Thanks man!

Nick, that is a great idea! I was thinking of going to get mic stands etc at garage sales. I think the pipes would work great! Thanks!

Alvin

[MasterZap]

Master Zap - I'm not sure what is a pan/tilt/zoom or unshake node - could you explain it? Or is it something that 3rd party trackers like boujou do best? You aren't refering to the corner pinning function right?

A pan/zoom/tilt camera move is a move in which the *position* of the camera never changes - only the direction it points (or the zoom). These are easy to track, and most softwares has a special mode for this (because they can solve the equations much easier since the camera position are not an unknown). Pan/Zoom/Tilt can be easily solved with primitive optical flow tracking of features, and you only really need a handful, and you don't need to measure anything, ever.

An "unshake" would be something even more simple. It would track one single point in the footage, and move the yaw/tilt to follow that point, i.e. it would not do "zoom", and it would not do "tilt" (i.e. camera leaning would be unsupported...)... i.e. exactly the motion you get on a tripod with no zooming. It owuld only need ONE POINT tracked to follow exactly.

But max doesn't take either into account and only does a "full solve", and hence *requires* off-plane markers, even if you do a simpler move which wouldn't need them.

Anyways, this is one of the methods I setup for camera tracking. This is for small areas, using 3cm dots in a 30cm grid. I track the dots individually, then just run the camera match. Usually there will be some cleanup with the low pass or straight filter on the camera.


Well, that room is somewhat clean so you may need tracking markers... but for a simple "tripod pan" you wouldn't need any markers, the features of the room would be enough. And no measurements needed either.

See this (http://www.lysator.liu.se/%7Ezap/kidwars/kidwars-2-new-trailer.wmv) for example of pan/zoom/tilt tracking.

/Z

[GallenWolf]

Hey thanks for the explanations man! I get it. Wonder why it's not included in max. Oh well....

btw, I tried tracking my short clip using voodoo. It locks on pretty well, but once imported in max the places that I place my dots are off-plane. Any way I could solve this? With the built-in tracker at last I got a flat ground plane, easy work on....

Still very noob to matchmoving, went out to get the book by tim dobbert (matchmoving: the invisible art of camera tracking) but it was out of stock :( Gah amazon or ebay time.

Thanks!

Alvin

PS: Saw the clip. Nice stuff! Very amusing :) I believe I understand what you mean by that kind of tracking.

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