This is a proposal to support unification of skeleton streaming formats and enable a braoder compatibility between mocap systems and realtime 3D softwares This has been shared alsready with major harware vendors and implemented in some Dassault Systèmes solutions It is here proposed as a reference to support a potential integration directly within VRPN

1. 1
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V6 unified Skeleton for
Real-Time Mocap
David Nahon, iV Lab. Director
david.nahon [at] 3ds.com
Draft3 – June 2013

2. 2
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Provide an unified skeleton for Live Motion usages
Facilitate animation process for applications (mocap)
The goal:
V6 Skeleton ReferenceMocap system
Stream joints of
computed skeleton
{pos, quat}
Applications
Infrastructure
CATIA
DELMIA
3DVIA
…
<configuration file>
VPRN Client
VRPN Protocol
Capture user datas
Compute animated skeleton
Real time Streaming over VRPN
Mapping between Mocap datas and the V6 Skeleton
VRPN client and mapping configuration embeded
It’s the same V6 Skeleton for all apps
Character animation with V6 Skeleton
Gesture and other motion-based interactions

3. 3
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V6 Skeleton Definition Internal Skeleton’s hierarchy
V6 Skeleton’s structure:
V6 Skeleton has an internal hierarchy (and no IK)
Segments have position and orientation
Segment length is expeted to be constant during Mocapc
Spine specification:
V6 Skeleton needs position and orientations of 4 Spines
(animated or interpolated by Mocap System) (?)
Spines height is regular (?)
Low height needed between Pelvis and Spine 1 (to ensure
good bend for low back and belly) (?)

4. 4
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V6 Skeleton Definition
right-handed coordinate system
x
y
z
V6 Skeleton’s local coordinates system:
Coordinates systems are right handed
Y axis is along bones
Z axis is forward bones except in the feet
X axis are coplanar into the plane made by the whole bones
(except the feet bones)
Skeleton T pose

5. 5
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What should be provided by eTP partners 1/2
Ensure constant segment lenght trough mocap
Reliable data:
Occlusion are solved and interpolated so that this issue is hidden to V6
Jittering and drift are filtered out so that this issue is hidden to V6 (a “keep on floor”
filtering could be provided)
Avoid interpenetrations between segments (especially during interpolation processes)
Provide calibrating methodology

6. 6
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What should be provided by eTP partners 2/2
VRPN communication:
All segments are expected to have been updated consistently on each frame
The coordinates of the segments are given in absolute coordinates
V6 Skeleton has no Invert Kinematic
Enable MOCAP for multi-users (1 tracker by user)
Use the standard naming provided by DS for the VRPN Trackers (see next slide)
Please name the option in the software:
« Dassault Systemes Live Motion standard v1»

7. 7
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Use the following rules for VRPN
tracker naming
SkeletonSegments Sensor Id
Pelvis 0
UpperLeg_L 1
LowerLeg_L 2
Foot_L 3
Toe_L 4
UpperLeg_R 5
LowerLeg_R 6
Foot_R 7
Toe_R 8
Spine1 9
Spine2 10
Spine3 11
Spine4 12
Shoulder_L 13
UpperArm_L 14
LowerArm_L 15
Hand_L 16
Shoulder_R 17
UpperArm_R 18
LowerArm_R 19
Hand_R 20
Neck 21
Head 22
Each user has one tracker: name User0, User1… each
Tracker added for new user.
User0 is the default Tracker for the first user tracked
Each User has 23 Trackers that correspond to the skeleton’s
segments
Each Id of the Tracker correspond to a segment of the
skeleton as given in the following table

8. 8
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