Keyframe for hip root bone
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Author:  jorgeo [ Wed Mar 01, 2017 12:58 pm ]
Post subject:  Keyframe for hip root bone

Sometimes because of shadows or occlusion from limbs, the location & orientation of the hip bone is not calculated correctly during Refit Pose. I fix and rotate it manually, then I have to use IK to try to fit limbs accordingly since the whole pose rotates with the hip. However, more often than not, hitting Refit Pose will undo everything, including the manually adjusted hip rotation.

Could it be possible to have keyframes for the Hip bone? Something optional, similar to the finger keyframes? It would essentially lock its rotation in place for that frame (or set of frames).


Author:  Snapz [ Wed Mar 01, 2017 8:49 pm ]
Post subject:  Re: Keyframe for hip root bone


What recording device is being used, and how many?

Are you saying this hip offset is occurring throughout the entire takes consistently?

Should be able to correct any issues like that with an adjustment layer in most 3D editors after export also.


Author:  jorgeo [ Wed Mar 01, 2017 9:06 pm ]
Post subject:  Re: Keyframe for hip root bone

I'm using 6 PS Eye cameras, recording some stretching exercises.

The hip offset seems to remain throughout the whole pose. Normally, fixing manually and tracking backwards and/or forwards works, but in several cases it just reverts to the incorrect pose consistently, like below.


The issue is that because of the hip offset, limbs also end up in the incorrect position. For example, in the image, the right foot is not on level to the ground because the whole right leg is already stretched to the max due to the right hip being incorrectly rotated.

Author:  Snapz [ Wed Mar 01, 2017 9:42 pm ]
Post subject:  Re: Keyframe for hip root bone


Thanks for the image... Can you post an image with the skeleton showing a bit more through the iPi actor in that view? What spine flex are you using? I would think very flex spine?

So, this just happens randomly then, here are some suggestions that may help.

Many times this happens when the hips are set too high, have you tried adjusting the lowest point of the pelvis with the leg length slider to meet the groin area?
(thigh joint at center of the butt from a rear view).

A better thigh joint/hip height should be measured to where the bend crease in the actor mesh would be, not to the top of your pelvis bone, I say this because it looks like the hip is catching the blue of the shirt and pulling the hip with that color as you stretch forward.

Make sure the actor height is very close to your actual height also, you can adjust the height to get the colors picked first, (if you didn't save an actor file yet), then just set it back to your actual height and let the refit snap it to the video, may take clicking refit a few times. (save your actor file after that).

You may also be getting a little interference from the shiny floors and the windows light in that cams view, PS Eyes are very touchy to light, next time you record with a lot of ambient light as that, try setting the exposure setting of the camera to 60 and adjust the gain accordingly to get a less brightened recording. (turning auto gain off). It may take a couple of test recordings so you can see where you need to set the gain, but I would say in that room, probably 14-16 on gain would be a good choice.

Also, it does happen where iPi just registers the refit wrong and wants to keep snapping wrong no matter what you try, so, you can try if you haven't already, to just reload the video and start over, because even trying the remove all animation from ROI won't usually reset this.

Tucking the shirt in may help some also.


Author:  jorgeo [ Thu Mar 02, 2017 4:50 pm ]
Post subject:  Re: Keyframe for hip root bone

Thanks for the feedback!

I didn't realize the hip position would change with leg length. I'm playing around with that parameter and it seems some combinations of height / leg length / fine-tuning colors for actor clothing works.

I'll play with the exposure gains of the PS Eyes next time. Ambient light varies a lot every hour depending on the passage of clouds outside.

Author:  Snapz [ Thu Mar 02, 2017 6:07 pm ]
Post subject:  Re: Keyframe for hip root bone


OK good...

I forgot to mention you should also re-detect the actors colors to whichever camera is in use while tracking, each angle can, and most likely will change the detected colors. it may not be mandatory if the tracking is working ok, but if you start to get more errors from a specific camera, just do a quick auto re-detect, but better to try to stay with one main camera while tracking, unless there is an issue where you can't, it may be needed to switch views at points to get a better tracking, then switch back to main camera once past the issue part.

The variance in natural lighting changes will be decreased with the camera settings I stated and by turning off auto gain, auto gain allows the gain to change dynamically and that's not what you want in most conditions that involve natural lighting in recordings.

Hope it all works out for you, good luck.


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