Motion Control Camera

[TumikSmacker]

can you provide a little more info? :)

[uschi]

i´ve done only one job with moco...

..the data from the milo was very good, no need to tweak around

but i made a scetch of the set and all the distances (the high of the rails ....).

the typical camera data (+dof data)

don´t crop in the telecine

my advice is just talk with the moco peop´s and the one that goes to the telecine... tell them what data you need

is not so difficult

[danylyon]

Originally posted by TumikSmacker
can you provide a little more info? :)
What kind of infos.. I don't think I have them yet.. I'm just preparing myself.

Thank you uschi for your post.

I'm looking at the camera Attributes in Maya right now. Can I just go to the DP and ask what Focal Length he's shooting that scene? Is that a term he knows?

Film Gate & Film Fit? What's that about?

Originally posted by uschi
don´t crop in the telecine

:surprised: Right.. now that's something I wouldn't have thought of. But don't they crop always? Like the borders are normally not exactly aligned. (There aren't even exact borders on a 35mm film, I think)

Originally posted by uschi
is not so difficult
ah relief.. and I already thought it's as difficult as motion capturing.

[danylyon]

And what about lens distortion?
Can I ignore that or is there a setting somewhere?

[stunndman]

i can't really give you any useful advice here - but you might want to take a look at the VFX challenge forum - http://www.cgtalk.com/forumdisplay.php?s=&forumid=67 - maybe there's some useful information in there as the challenges always include some kind of live footage

[stunndman]

and have you read through the live manual? there's a lot of information on filmback and aspect ratios and stuff like that

[danylyon]

Thanks for your post stunndman.. I'm not talking about Maya Live, I'm not tracking anything. It's a Motion Control Camera (so The Camera Path can just be loaded in).

The Help is a good Idea though! :cool:

I'm still wondering about the Lens Distortion.. but I'll just ignore that for now. (And ask the Motion Control Guy)

[danylyon]

The job is done now..

But the implementing of the Motion Control Path wasn't exactly easy. That's why I wrote a little tutorial.. so here it goes:

First, let me explain, how to EXPORT a camera path of this kind.
Open up Maya. Create a "Camera and Aim at", because we used Target tracking, which means we had an X,Y,Z coordinate of the Camera and the Target (the Aim at).
Let's export this "Path" (it's just one position). Chose "File" -> "Export Selection" Options Box.
The File Type we're going to use is "move". A move File is just a list of Keyframes without any attributes or objects. There's always one entry for every Frame.

Now, we need to choose the attributes we want to export. Under Attributes, you need to list, which attributes to export and the EXACT order.
For our Path, we need:

camera1.tx
camera1.ty
camera1.tz
camera1_aim.tx
camera1_aim.ty
camera1_aim.tz

You can select those attributes in the channel box and press "From Channel Box".
Press Export Selection and save the file. Open it in an editor to see how it looks. You should have 5 rows with a lot of 0 and one with -5 (because our camera was on position 0)

Now you need to adjust your data from the MoControl system to match these rows. This is a little bit of a tricky part.. but with some knowledge of MS EXCEL or an editor that lets you select rows, you can match it. (The file doesn't have to look that clean in the end.. if you have more or less spaces between the numbers, maya will just ignore it)

Befor you import, you need to make sure, that you have set your preferences in Maya correctly (check the Up Axis and the Working Units).

Import the .mov file (File -> Import). You will notice, that there's no way to select how maya should interpret the numbers in your .mov file. It actually takes just the settings from the Export Selection Options box, which we set correctly above.

Now, if you import the footage, it should match.. theoretically.

The Problems that arised in my case (and might solve some of yours)
- The x coordinate was flipped, so I had to change all falues in the .mov file
- The MoControl Rig was probably not calibrated correctly, that's why long scenes didn't match throughout.
- The Focal Length of the Lens didn't match. I had to adjust it manually. (actually by testing in a 3D tracking software)
- Macro shoots aren't stable on an "ordinary" MoControl system.
- The Roll Value can be entered into the Rotate Axis of the camera1, it should be possible to import one row of numbers into that value too, althoug the value might be flipped aswell.

You can go ahead now and import this camera path into After Effects. Just Bake the simulation of the camera1 (Edit -> Keys -> Bake Simulation) (so that the camera1_aim isn't needed anymore). Save the file as a *.ma (Maya ASCII) and open it in After Effects.


I hope this helps someone.. sometime. :)

[boomji]

heyyy!!!,
read this late :( .But sharing your experience was a very generous thing to do...thanx.
About the lens distortion i think you would shoot a grid(drawn on thermacol or something) and adjust your camera or distort filter in post.

thanx for sharing.
b

[danylyon]

Originally posted by boomji
About the lens distortion i think you would shoot a grid(drawn on thermacol or something) and adjust your camera or distort filter in post.

Yeah exactly.. that would be a way to do it.. and I found out that Icarus (http://aig.cs.man.ac.uk/icarus/) can remove lens distortion from a series of images.

Luckily I didn't need that, professional lenses are normally built the way that they give almost no distortion.

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