[x3d-public] X3D working group meeting: SFTime

Don Brutzman brutzman at nps.edu
Wed Apr 25 10:01:05 PDT 2018

Attendees: Nicholas Polys, Dick Puk, Don Brutzman.

1. *Conference and Meeting Planning*.

a. Web3D 2018 Conference and VR Hackathon: registration is now open for each event, early-registration discounts end May 10.

	Web3D 2018 Conference, Poznan Poland, 20-22 June

	VR Hackathon, Poznan Poland, 18-20 June

b. Cyberworlds 2018.  Submission deadline in another 2 weeks, conference hosted by Fraunhofer Singapore 3-5 October 2018.


c. ISO SC24 annual meeting near Toulouse France, 6-10 August.  Dick and Don will attend.

d. SIGGRAPH 2018 in Vancouver 12-16 August.  Registration is open.



2. *Humanoid Animation*.  This group is super active, preparing Draft International Specification (DIS) for HAnim Architecture and HAnim Motion Animation.

a. /New tool support/

Announcement from Suwon University announces HAnim support for converting Maya/Max humanoids via VRML97 to X3D:

	[h-anim] WRL to H-Anim X3D conversion tool

> Dear All,
> We are pleased to release the WRL to H-Anim X3D conversion tool.
> The tool can be downloaded at the following link on the Web3D KR Website:
> http://www.web3d.kr/fsboard/fsboard.asp?id=e_si
> The procedure for using the tool is as follows:
> -----------------------------------------------------------------
> Procedure to obtain an H-Anim X3D character file using the Suwon H-Anim
> viewer
> 1. When creating an H-Anim character using MAX or Maya, make sure each
> object has a precise segment name with a joint center point based on the
> H-Anim LOA hierarchy.
> 2. Export the H-Anim character file to a WRL file using a tool such as MAX
> or Maya.
> 3. Unzip the WRL-to-HAnim X3D zipped file.
> 4. Open the Suwon H-Anim viewer.
> 5. Open the LOA1 or LOA2 H-Anim WRL file using the File menu at the top of
> the viewer.
> 6. Provide an H-Anim X3D file name and click the OK button.
> 7. Use any X3D viewer to display the H-Anim X3D character.
> -----------------------------------------------------------------
> Currently, LOA1 and LOA2 character models can be converted. LOA3 and LOA4
> conversion is coming soon.
> Please note that functions other than conversion may not yet work as
> expected.  Fixes are coming soon.
> Sincerely,
> Myeong
> -- 
> Myeong Won Lee
> Faculty of Computer Science, College of IT, U. of Suwon
> Hwaseong, Gyeonggi-do, 18323 Korea
> Tel) +82-31-220-2313, +82-10-8904-4634
> E-mail) mwlee at suwon.ac.kr

Pretty exciting news!  Test reports welcome.  We will discuss further on the weekly HAnim Working Group teleconference, today 5pm pacific (Thursday morning in Korea) on the Web3D Teleconference line.

	Humanoid Animation (H-Anim)

	Teleconference Information
b. /Open naming question/ for Humanoid Animation specification.

*Is it OK to change acronym from H-Anim to HAnim?*  Motivation is to improve searchability and also consistent representations across X3D file formats and programming-language bindings.  The group is requesting feedback and expects to resolve the issue soon.

c. /Specification publication: draft HAnim DIS document/.  In order to encourage public review of drafts for this major specification change, the Web3D Board of Directors has approved public availability.

Online at Web3D website > STANDARDS > H-ANIM, or directly at

	All H-Anim Standards

d. /Planned work: HAnim tables/.  Further work is planned by Joe Williams and myself to update some helpful assets as part of the draft specification review.

If you navigate to

	X3D Example Archives: Basic, Humanoid Animation

... there is a sentence "Tool builders may benefit from using convenient tables of enumeration values extracted from the HAnim Specification."  Link:

	H-Anim Tables of Names and Features

We plan to meet on teleconference line Thursday 2:30-3:30 pacific to get going.

e. /HAnim video competition/.  Note that the competition period is ongoing, submission deadline is in one week: 30 April 2018.

	H-Anim 3D Animated Music Video Competition​ 2018

f. /Continuing work/.  Task list progress is maintained at

H-Anim Specification Task List for DIS Submission

Help needed: interpolation of measurements for default joint/segment values of LOA-4 hand and feet.

X3D v4.0 draft specification prose for HAnimMotion node: maybe next week.


4. *SFTime design discussion*.  Review of schema constraints on SFTime values uncovered a curious issue.  Background email thread:
	X3D JSON Schema Updates: determining event constraints for SFTime durations and timestamps

Summary:  most uses of time values in X3D scenes are for current system clock.  Nevertheless the X3D Abstract Specification allows and defines negative SFTime values as well.

Key references and excerpts:

5.3.15 SFTime and MFTime

"Time values are specified as the number of seconds from a specific time origin. Typically, SFTime fields represent the number of seconds since Jan 1, 1970, 00:00:00 GMT. The default value of an uninitialized SFTime field is -1."

8.2.2 Time origin

"Time (0.0) is equivalent to 00:00:00 GMT January 1, 1970. Absolute times are specified in SFTime or MFTime fields as double-precision floating point numbers representing seconds. Negative absolute times are interpreted as happening before 1970. Processing an event with timestamp t may only result in generating events with timestamps greater than or equal to t."

So X3D functionality includes precise referencing of past and future times.  We had an interesting discussion of various aspects and did not identify any difficulties.

Summary and resource links can be found in X3D Tooltips.

	X3D Tooltips: SFTime
> SFTime> Single-field time value in seconds, specified as a double-precision (64-bit) floating point number, 15-17 significant digits, maximum value ~1.8 × 10^308.
> Example values: 0, 10, or -1 (indicating no actual time value is provided).
> Hint: Time values are usually either a system time (matching current clock time) or else a nonnegative duration interval in seconds.
> Hint: Typically, SFTime fields represent the number of seconds since Jan 1, 1970, 00:00:00 GMT.
> Warning: -1 is default initial value, typically indicating no updated time value has yet been provided.
> Hint:   X3D Abstract Specification, Time component, 8.2 Concepts for time model, time origin, discrete and continuous changes, time-dependent node cycles and activation, pausing time, etc.
> Hint: see Wikipedia: Double-precision floating-point format > Hint: see Wikipedia: Time and System time 

No X3D specification changes appear to be needed.  The editors will consider whether to add a cross reference in the abstract specification.

Related work, independent of SFTime: the Design Printing and Scanning Working Group is considering MetadataDate representations.


5. *Upcoming meetings*. Tomorrow:  spec editors call working further on HAnim, 1530-1700 pacific.

/Next week/.  We will take another look at draft C, C++, C# specification bindings.  We are hoping to get awareness/participation from potential implementers:


CoVise OpenCOVER



Instant Reality

This is also a likely topic for breakout discussions at Web3D Conference.


All feedback welcome.  Have fun with X3D!  8)

all the best, Don
Don Brutzman  Naval Postgraduate School, Code USW/Br       brutzman at nps.edu
Watkins 270,  MOVES Institute, Monterey CA 93943-5000 USA   +1.831.656.2149
X3D graphics, virtual worlds, navy robotics http://faculty.nps.edu/brutzman

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