[Korea-chapter] [X3D] CAD Working Group meeting (17:00 PDT, March 14th) - minutes

Don Brutzman brutzman at nps.edu
Wed Mar 14 19:00:53 PDT 2012

Attendees:  Hyokwang Lee, Dick Puk, Myeong Won Lee, Vince Marchetti, Don Brutzman

1.  We reviewed previous working group minutes, particularly the
2012 Feb 23 teleconference.

Of note is that working group members need to use the mailing-list
account and password to access these minutes.  If you need to reset
your password, or subscribe a different address, you can go to the
following page:  http://web3d.org/mailman/listinfo/cad_web3d.org

We are all glad that teleconferences are proceeding among all three

2.  Interesting demo noted in those minutes:


> Displaying dynamic CAD models with X3DOM and WebSockets
> January 9th, 2012 
> This external showcase by Tampere University of Technology, demonstrates displaying CAD-imported models in browser and changing the model on-the-fly from a simulation.
> X3DOM is used to render a X3D model exported from a native CAD application. The model is update REAL-TIME from a Matlab simulation model. It also integrates the 3D view with our other tools like semantic search by capturing DOM events (video around 2:53). Interfacing with the simulation from the browser is done via WebSockets. It displays the performance X3DOM is capable of: latency for visualization is constantly less than 50-100 ms.

3.  We discussed whether CAD group might meet at Web3D Conference
prior to SIGGRAPH this summer.  Should we have a workshop or demos?
Lots of possibilities...
	Saturday-Sunday 4-5 August 2012

	Sunday-Thursday 5-9 August 2012, SIGGRAPH

Wondering if we might have an working group meeting during afternoon
of Friday 3 August?  If the foreign travelers can support a 3-4
hour meeting prior to the conference, that would be very productive.
Perhaps something like 2-6 or 3-7 pm at a hotel, then dinner.

We could follow this with a 30-60 minute update briefing during the
Web3D conference.  Or someone can give a paper...

We can also schedule a one or two-hour BOF during SIGGRAPH.  Many
people attended these last year, typically over 100 people each time.
So we could use that opportunity to tell people what we are doing.
This seems like a good idea.

Anita can you ask SIGGRAPH to schedule a 1 hour BOF for CAD,
along with the other Web3D BOFs?

On 3/14/2012 2:36 AM, Hyokwang Lee wrote:
> Correction : PST -> PDT
> It will be 5:00pm PDT and 9:00am KST.
> Hyokwang Lee
> *From:*Hyokwang Lee [mailto:adpc9 at partdb.com]
> *Sent:* Wednesday, March 14, 2012 2:40 PM
> *To:* 'x3d at web3d.org'; 'cad at web3d.org'
> *Subject:* CAD Working Group meeting (17:00 PST, March 14th) - Agenda
> CAD Working group meeting is on March 14, 2012 (2nd Wed) at 5:00pm PST. (Thursday at 10:00am KST)
> Agenda items from Korea Chapter for CAD WG teleconference are as follows.
> - Issues from the previous Eu-Kor meeting (reactivated)


> * Sharing with Google Docs

some discussion.  since all items are placed on the wiki for everyone
to see, this would seem to be a convenience during meeting discussions
and not a requirement.

> - CAD data representation
> * B-REPs rendering based on NURBS component

Vince continues to note potential improvements to the NURBS component.
Dick and I will review and comment on his spec suggestions.
Vince and I will again ask Yvonne (details below).

> * STEP(B-Rep) to X3D conversion

Hyo is making a Step to X3D converter.  He has lots of
questions for Vince, the expert on this topic!

- holes can be cut in cylinder end, but only if flat (not warped, not notched)

good reference:  _The NURBS Book_ by Les Piegl and Wayne Tiller

	section 6.1 is especially important,

updated source code, apparently quite expensive:

Another interesting code source identified to Vince by Christophe:
jgeom library.  Seems to have fallen off the web, inquiries at:

More potential NURBS support may be provided by VTK.

A very old reference using VRML is

Vince is primarily using Python for his NURBS work.

relevant quote:

	"He who refuses to do arithmetic is doomed to talk nonsense."
	John McCarthy, 1927-2011

Hyo will follow up with Vince to cover further questions.  They will
copy the list.  Point Inversion and Projection for Curves and Surfaces.

> * CAD geometry component test

We looked at

32.4.1 CADAssembly

CADAssembly : X3DGroupingNode, X3DProductStructureChildNode {
  MFNode   [in]     addChildren
  MFNode   [in]     removeChildren
  MFNode   [in,out] children       []       [X3DProductStructureChildNode, X3DGroupingNode]
The CADAssembly node holds a set of assemblies or parts grouped together.
The children field can contain X3DProductStructureChildNode types. Each child will be either a sub-assembly or a part.

Note that this means only X3DProductStructureChildNode or a Grouping node
can be contained, other nodes cannot.

This test is not validatable via X3D DTD or X3D Schema.
Proper children will be allowed, but others won't be blocked.

Similarly, in 32.4.4 CADPart, the only allowed children are CADFace.
The X3D DTD and X3D Schema do strictly check for this.

I will add rules to X3D Schematron to diagnose each case.

> * Comparing vocabularies of MPA/STEP/X3D-NURBS/X3D-BREP(proposal)
> - Other issues
> * ISO TC 184/SC 4 : Standardization of JT
> * Creating good CAD examples (Vince published a lot!)

We discussed Vince's examples at

	Mobius Nurbs

There is still an unresolved issue with Instant Reality.  We
asked Yvonne Jung to look at this, but we haven't reached
resolution yet.  Vince's comments and site with more information
about this are at


Yvonne, can we ask you for a dedicated call about this?
How about

	Friday 23, 0730-0800 EDT, 1030 EDT, 1630-1700? Germany

Vince also described his work on the wiki at

He improved some of the CAD models, described under Viewpoints
section on the wiki.  We will add those to the X3D Basic archive.

> * CAD Wiki

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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