Blade 3.1 / 3.3. 1 Summary

Blade 3.1 / 3.3.1 Capturing ROM

Deborah R. Fowler

click here for Blade 3.1 / 3.3.1 User's Guide

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Posted on Dec 5  2013
Updated Mar 25  2016  

Blade 3.1 / 3.3.1 Calibrating Actors - Capturing ROM

ROM (Range of Motion) - bend every joint to their limits

Capturing is the process of recording all 2D camera data. When capturing, only 2D camera data is recorded, although you see 3D data in your workspace. Once saved, the data can be processed offline, providing the 3D "reconstructions". Note we use a t-pose because autolabel looks for this and in addition, characters models are easy to append skeletons to the models.

Your database should have already been set up!!! If for some odd reason it has not - make sure it is in place now. See database setup.

Marker Placement

We are using a passive optical system; markers are made of tiny glass beads, 3M retro-reflective tape would work too. Space defined by inside the lines of tape, using 4M Pixel cameras. Marker positions match the vicon skeleton template.

Marker Placement for Vicon Blade 3.1 and 3.3.1
     53 markers total  (when doing fingers there will be 59 total) CLICK BLUE LINKS BELOW FOR PICS
  • 10 on feet (5 each, one on the front, 2 on the broadest part of the foot, 1 on or above the angle bone, one on the heel)
  • TIP: on the broad part of the foot - ensure the inside marker is further forward than the outside marker)
  • 16 on arms (4 on each hand, 2 each side of elbow, 1 each upper/lower - on the hands, make the top two flat and the two on the sides of the wrist. On the elbow, close to the bone.)
  • 4 on shoulders (2 each, front/back) TIP: the shoulder marker should not move when moving your shoulders
  • 2 on chest (on at the base of the sternum, one at the clavicle - correspond to bone protrusions)
  • 2 on back (on as if an arrow had gone thru the sternum, TIP: one at the base of the neck where it bends)
  • 6 on hips (this should be where the bone sits - 3 on each side)
  • 5 on head (2 front, 2 back, 1 top - use the velcro strips to ensure a "box" is formed around the head far enough from the ariel)
  • 4 on knees (2 each side, TIP: offset forward slightly so not knocked off in motion - close to the knee caps)
  • 2 on lower legs (one on each leg - but there are unlike the others, purposely non-symmetric)
  • 2 on upper legs (as above but on the thigh rather than calf region)
  • Additional pictures of front and back full body view
     Don't be afraid to ask your actor to bend so you can place the markers more accurately.
     The thigh and mid-calf markers are slightly offset to allow the software to distinguish right/left
     Hint: Wiggle the velcro markers a bit on the suit to help them stick (particularly the hands/feet/knees)

Why this way? The skeleton in the software is defined in this way so that it understands this configuration. It corresponds to this set up when labeling the markers and creating the skeleton.

Note - in 3.1 / 3.3.1 a vsk (autosaved) and vss (manually saved) file are created ... read on

Hint: If the velcro markers are not sticking properly, wiggle them a little on the material.

Capture ROM

Under the Studio Activities tab, click on the Capture Layout button to reconfigure the Blade workspace. In the Capture pane, enter a take name appropriate for a character range of motions (ROM). Label such as DeborahROM.

Now capture the range of motion. It is important to have the actor go through the extent of the movement his body will perform during the subsequent captures. This looks somewhat like a stretching/yoga/exercise class but the goal is to inform the software of how much movement will happen - so exercise all rotation extremes for every joint.

Typically we practice a ROM with the following movement (movements added recently are in italics):

ROM Movements

Correct T-pose has feet straight forward, shoulder width apart, arms out straight like a T, not above or below the shoulders

Hint: splaying your fingers may help you remember to keep your arms in the right position - try it.
  • start in t-pose
  • "neck rolls" - circularly rotate the neck around, both directions
  • "arm parts roll" - circularly rotate the wrist, arms from elbows, arms from shoulders, big arm circles - both directions,
  • "butterfly" - swing your arms out and to chest
  • "leg parts roll" - circularly rotate your foot, leg from the knee, leg from the hip, repeat for each leg
  • "cowboy legs" swing your legs outward to the side from the hip, repeat for each leg
  • "kick and kneel" - swing you leg back and forth, go down on one knee (touch your arm to opposite knee) repeat for each leg
  • "hula-hoop" - swing your hips
  • "side bends" - flex side to side while facing forward
  • "back flex" - touch your toes and then look up at the ceiling with your arms outstretched, bending backward
  • (if you are doing finger capture, add finger wiggles as well)
  • return to t-pose

Start the capture, perform the above movements and end your capture. The provided information to create an accurate skeleton for vsk. In other words, it defines the constraints of motion for the skeleton.
Next we will process the ROM

NOTE: In the Perspective view, right-click on the context menu and click Show Trajectory Count (from the Capture a Range of Motion page in the documentation) to confirm the number of markers.