foot,wrist,head tracking

khatarat · **Joined:** Fri Jul 13, 2012 1:24 am **Posts:** 13

hi
i want to have a good foot tracking. in my captured files all parts are good but foot is not tracked good. what should i do?

is it possible to track wrist and head with version 2.

Greenlaw · **Posted:** Mon Aug 13, 2012 10:08 am

For feet tracking, I assume you have Foot Tracking enabled. If not, try that.

After the initial tracking, you may notice some 'bouncing' in the joints (and not just with the feet.) You need to use Configurable Jitter Removal to stabilize this. I find that I typically need to apply strong CJR to the legs and can apply a lot less for the arms and torso. If you vary CJR throughout the shot, be sure to 'touch' Trajectory Filtering to smooth out the transition between changes. (By 'touch', I mean set TF to a different value and then return it to the value you want. This forces iPi Studio to smooth all the curves in the rig.)

If it's a 'heel rotation' error (as opposed to feel sliding positionally), what you're probably seeing is a limitation of the rig. If the performer twists his body a certain way, the rig cannot match this twist through the body and legs. What this looks like is unnatural pivoting at the ankles. I was told that if they allowed this twist, it might cause more serious problems elsewhere. Luckily, you won't see this error often. Unfortunately, when you do see it, it can't be corrected easily in iPi Studio.

You can fix this problem in some animation programs by pinning the ankle joints. In Motion Builder, for example, you can temporarily pin the rotation (and position if you wish) of an ankles joint to an effector, and unpin it when the foot needs to move again. Other animation programs may have a variation of this technique.

Good luck!

Thought for iPi Soft: I wonder if a feature like this could be added to iPi Studio in a future build? That would be very useful to users who don't have Motion Builder.

G.

Greenlaw · **Posted:** Mon Aug 13, 2012 10:11 am

As for head and wrist, iPi has a tentative schedule for feature releases on the main website. Currently, head and wrist tracking is slated for fall or winter. Schedules are subject to change of course but the update should be free to registered 2.0 users when it comes out.

G.

khatarat · **Joined:** Fri Jul 13, 2012 1:24 am **Posts:** 13

i didnt understand this part:

Quote:

be sure to 'touch' Trajectory Filtering to smooth out the transition between changes. (By 'touch', I mean set TF to a different value and then return it to the value you want. This forces iPi Studio to smooth all the curves in the rig.)

can you explain more? what should i exactly do?
my main problem is that when foot does not move in output the foot has rotation.

Greenlaw · **Posted:** Tue Aug 14, 2012 9:36 am

Look at this video and scrub to 0:18 and look at the feet. Is this what you're talking about? If so, this is caused by twisting--the rig does not pass the twisting down the body to the feet, so you wind up with rotation at the ankles. This is the rig limitation I've described above and you cannot fix this issue in iPi DMC (at least not in the current release.)

You can fix it in 3D animation program that allows you to pin joints and use and envelope to turn this on and off. Many 3D programs have some technique for doing this.

Alternatively, you can perform to avoid this problem. With practice, you can make this work without looking too unnatural. Another option is to simply avoid showing the feet in you production (shoot 'cowboy' style.)

Tip: Before working on a film, I carefully storyboard all my shots and think about where it's important to show feet and where it isn't. If I don't see the feet in a shot, I simply do not worry about this problem during capture and tracking. When I do see the feet, it's typically in a wide shot and I can't tell that the feet are rotating anyway. However, if the rotating feet are clearly a problem in a shot then I will fix it in my animation program.

Regarding "'touching' the TF control," Trajectory Filtering applies smoothing over your entire animation. This is not the same a Jitter Removal, it's just a global smoothing tool that reduces the most extreme 'bump' in your animation and it has less effect on smaller 'jitters'. If you turn this up too high, your motions will start to look more 'robotic' because all the character will be smoothed out.

Where it's useful in the situation described earlier, you can use it to smooth the transition between different Configurable Jitter Removal settings. When using CJR, you can use different settings at different ranges of your motion. When you do this, however, you may notice 'bumps' or jerkiness when the settings change. To smooth this, just move the TF settings to a different value and then back to the setting you had--this will smooth the bumps between different CJR settings without affecting the CJR very much itself.

BTW, TF is non-destructive so you can keep changing it without worrying about it smoothing your motions too much permanently.

Hope this helps.

G.

benposey · **Joined:** Tue Sep 11, 2012 12:19 pm **Posts:** 1

in future versions, would wearing a baseball hat help show direction the head is moving?

I thought perhaps that could work??

i'm using 2 kinects.

Is the head / wrist animation any better on ps3 camera's??

thanks

vmaslov · **Posted:** Fri Dec 14, 2012 5:15 am

Version 2.2.0.144 includes wrist rotation tracking using data from motion controllers.
Head tracking already works for pitch and bank rotations. Heading rotation tracking is on the way. Currently we do not plan to set any special requirements for head's look. Though we may have additional tips for improving head tracking after it is fully implemented.

Greenlaw · **Posted:** Fri Dec 14, 2012 11:12 am

Does head track strictly use the shape of the head to determine the rotation? I'm guess for Kinect this is the case since I understand you guys don't use the RGB data.

I was just wondering because sometimes I have a situation where the head will flip out completely and I'm not sure why that's happens. Any thoughts on how to minimize/prevent this? (Besides turning it off for that region I mean.)

I should mention that I haven't used the latest software update yet. We'll try to do some serious (dual Kinect) testing of new (and old) features in the next few days and let you know what I think. :)

G.

vmaslov · **Posted:** Fri Dec 14, 2012 1:06 pm

Yes, for currently supported head rotations we use ellipsoid approximation of head's shape. For Y rotation we will use RGB data of depth sensors as well to determine the face position. Now we can do this thanks to good RGB-depth alignment.
While implementing face orientation tracking, we also will work on X and Z rotations tracking improvements. I think we will get better understanding of what is good and bad for head tracking, and produce some tips for users.

Greenlaw · **Posted:** Fri Dec 14, 2012 3:24 pm

vmaslov wrote:

For Y rotation we will use RGB data of depth sensors as well to determine the face position. Now we can do this thanks to good RGB-depth alignment.

Very cool guys! The thought did cross my mind but I didn't know if the new RGB alignment would be accurate enough to match the point cloud. I'm not at all surprised to hear that you're already on it. :)

Thanks for the info and please keep up the fantastic work!

G.

foot,wrist,head tracking

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