Heads/body jolts and Ground captures

[dtaylor112]

Hi All,

OK, so I've been working with Optitrack for a couple of weeks and overall it's a cool setup however, I'm have a few issues that are happening consistently.

1. The 'Head Jolt': I'm noticing at random times (and just about every take) there's a point where I will move my head either from Up to Down or side to side and my head looks like it's on a swivel. Example: I'll look up as if looking at something in the sky and then I will look to the floor and when I play back the footage it looks like my chin goes into my chest and they it snaps back up. ONLY in that one spot... I check the graph and it's a spike that I can never fix (I've tried using the "move" tool and the "smooth" tool - nada)

2. For some reason the cameras to NOT like the floor. I've actually moved the lower cameras from about 5' high down to about 4' high and when I lay on the floor my skeleton rolls up into a ball and starts to levitate above the floor... I stand up and move around and it's back to normal... how low do I actually have to lower the cameras in order to capture the floor? (Note: My capture area is about 15 x 12 with an 8 camera set up)

3. I've noticed that at some point during the capture, things just go awry. Like last night... I captured about 5 really decent motions... I start on the 6th motion and BAM! One shoulder is higher than the other, the other shoulder "pops" up and down in a snapping motion... my head gets stuck looking to the side, I have to take off the hat and put it back on... the works. Do the cameras get hot or something? I have NO idea what's going on and it's crappy takes for another 4, 5 takes... I shut down everything, reopen the software/cameras and it's fine again, sae exact suit/camera positions & lighting as before... confusing.


Any suggestions on these three?

[VincentG]

1 & 3 - Can you please send us some copies of your calibration file, skeleton, t-pose, and captures?

2 - When initially setting up the cameras -

a - how high are the upper cameras?
b - have you tried roating the cameras 90 degrees?
c - When aiming all 8 cameras, are they pointed towards a center point (middle of the capture volume), at waist high?
d - Can you send us a capture of this occuring as well?

[dtaylor112]

1&3 - okey dokey... I will probably do a few more captures this weekend but I've done the bulk of the captures already (I'll need to tweak them in Poser)... just these last few take place on the floor.

2:

A. About 9 feet high

B. I started to and rotated the 4 lower cameras and it was too late to realize I needed to rotate all 8. (I capture after work and it was already about 12:30am) - the floor plane was at vertical so I repositioned all of the bottom cams so they're all upright again.

C. The upper cameras point at around the chest area. The lower cameras are (now) pointing more towards the feet. After lowering them I was still having issues with laying on the floor so I angled them DOWN more.

D. When I just lay on the floor I'm fine - but when I start getting up everything gets all wonky, I'll try to find that one and send it to you)

[VincentG]

I would try the following -

1 - Movethe lower cameras to 5'6" to 6' high, aim all of the cameras towards the center point, waist high.

2 - Rotate the bottom cameras 90 degrees

3 - Is the floor plane vertical after you run the calibration again. (needs to be run everytime the cameras are adjusted)

[Jim]

Hello:

We will review your data and give detailed feedback. For other viewers of this post, the following could be helpful:

- The Head Jolts could be caused by not having a unique rigid body for the head or hat on the head, it is a classic symptom of a symetrical triangle from the ears to the front of the head, try to make it very unique.

- Rolling on the floor is hard to do, even for us. If the cameras can't see the markers, or enough of the "important" ones, the skeleton will fail. Laying down can be easier, but getting up can cause pops. More cameras help this problem. I don't think you need to move your cameras at this point.

- Not sure why the system is having trouble after 4-5 takes, that doesn't sound normal. Sometimes users have other programs running in the background that can take resources, like anti-virus software, just an idea.

[dtaylor112]

Hey sorry I haven't sent the files yet, I'm rendering the CGI footage and it's clocking in at about 18 hours to render a 10 second clip... on BOTH of my computers. I will get those file to you ASAP though.

I do have a question about your last response. What is a "unique rigid body for the head"?

I created the skeleton that saw all markers and it works fine for the most part - do I need to take an additional step to create a unique rigid body for the head?

[tvining]

Hi Koan,

This is a little off-topic, but 18 hours for 10 seconds sounds like a lot--are you rendering in Poser? I've found Poser to be really slow to render in. I use Poser (Daz) figures as well, but I've always used Cinema 4D for rendering, and it's a lot faster, and there are plugins for other 3D packages. If you have access to any of these packages, you might look into trying to render in one of them.

--Tim

[Birch]

[quote=Koan]
[quote=Jim]The Head Jolts could be caused by not having a unique rigid body for the head or hat on the head, it is a classic symptom of a symetrical triangle from the ears to the front of the head, try to make it very unique.
[/quote]
I do have a question about your last response. What is a "unique rigid body for the head"?[/quote]

Try to make sure the rigid body on the head is asymmetrical. Having each side be a different length will reduce the chances of the tracking engine confusing its markers and solving its position incorrectly. Basically, have the front marker is off to one side.

[bsteagal]

Sounds like he could be rendering in Vue also... 18 hrs is typical depending on what you are doing... I've had scenes take days to render depending on the quality...

My cheesecake commercial for example, took about 30 something hrs to render at broadcast mode..

www.kkstudio.us in the gallery..

Bryan

[dtaylor112]

Hello,

Major problems today. I'm rendering in Carrara now. It doesn't usually take this long but with a few renders I'm using anti-aliasing set on 'Best' along with some HDRI lighting... (HDRI is an animal)