[x3d-public] Extrusions, take 3

Tue Jan 26 18:00:32 PST 2016

If we support SVG, we may want to support 3D-SVG, where 2D is normal SVG, and a 3rd dimension specifies the “spline path” or path through 3D space—which may just be a straight line.

John
> On Jan 26, 2016, at 8:54 PM, John Carlson <yottzumm at gmail.com> wrote:
> 
> I think if we restrict Extrusions in V4+ to 2 spline points, that would work for me too.  An easy fallback for V4 products to support V3 might be to ignore all points in the spline except for endpoints.
> 
> I think that when SVG is incorporated, if it is, then Extrusions from SVG (meta-SVG?) will become important, so we may want to keep Extrusions around.
> 
> John
> 
>> On Jan 26, 2016, at 8:21 PM, John Carlson <yottzumm at gmail.com> wrote:
>> 
>> All I would really like to see is an easy way to define Cylinder with 2 endpoints and a radius.  If that is provided, I have no problem with deprecating Extrusion from the standard.
>> I do not think defining a Cylinder in this way would be onerous to a run-time, but I could be wrong.  If someone could provide an example of a Cylinder like this, it would be great!
>> 
>> John
>>> On Jan 26, 2016, at 8:13 PM, John Carlson <yottzumm at gmail.com> wrote:
>>> 
>>> Uh, I asked for an IndexedFaceSet.  Thanks, though.
>>> 
>>> John
>>>> On Jan 26, 2016, at 8:11 PM, doug sanden <highaspirations at hotmail.com> wrote:
>>>> 
>>>> 
>>>> http://dug9.users.sourceforge.net/web3d/tests/41.x3d
>>>> 
>>>> snake animation animating extrusion spine
>>>> 
>>>> From: x3d-public [x3d-public-bounces at web3d.org] on behalf of John Carlson [yottzumm at gmail.com]
>>>> Sent: January 26, 2016 6:04 PM
>>>> To: Leonard Daly
>>>> Cc: x3d-public at web3d.org
>>>> Subject: Re: [x3d-public] Extrusions, take 3
>>>> 
>>>> Maybe just show an example of an IndexedFaceSet which is an extrusion of a circle with 3 spline points, with the “bend” animated from 90 to 180 degrees.
>>>> 
>>>> It’s okay to use Blender or Maya, I’d just like to see what the results look like.
>>>> 
>>>> John
>>>> On Jan 26, 2016, at 8:01 PM, John Carlson <yottzumm at gmail.com<mailto:yottzumm at gmail.com>> wrote:
>>>> 
>>>> So how do you propose to animate IndexedFaceSets in a declarative or VRMLscript or JavaScript manner if they are Extrusions?  Can we see an example?  If the developer has to do it, can we help them?
>>>> 
>>>> John
>>>> On Jan 26, 2016, at 6:58 PM, Leonard Daly <Leonard.Daly at realism.com<mailto:Leonard.Daly at realism.com>> wrote:
>>>> 
>>>> On 1/26/2016 3:21 PM, John Carlson wrote:
>>>> Leonard, I think you forget that Extrusion splines etc. can be animated.  If Maya can export an Extrusion animation to X3D V4.0 and your new elements can handle animation of it, I think we are fine.
>>>> 
>>>> In Maya and Blender, extrusions are converted to IndexedFaceSets. These can be animated through the usual mechanisms in those applications. The results are typically stored in a FBX file. Unfortunately, the FBX format is not open and not too conducive to importing in a browser. Autodesk provides a C++ and Python API for accessing the file.
>>>> 
>>>> Extrusions are just a convenience node for creating a constrained IndexedFaceSet. I am working on exactly how X3D fits in the process chain from modeling tools to display. The goal is that X3D is an declarative archivable format that has a browser-based run time. The goal is to not reduce the display capability of X3D in that chain; however, not all of the functionality of X3D V3.3 is necessary to remain in the node definitions to make that happen.
>>>> 
>>>> Animation of the spline and cross-sections of an extrusion is much easier for the developer, but puts a much greater load on the run-time as it needs to re-triangulate the result on each animation.
>>>> 
>>>> 
>>>> Leonard Daly
>>>> 
>>>> 
>>>> 
>>>> 
>>>> 
>>>> 
>>>> John
>>>> On Jan 26, 2016, at 1:47 PM, Leonard Daly <<mailto:Leonard.Daly at realism.com>Leonard.Daly at realism.com<mailto:Leonard.Daly at realism.com>> wrote:
>>>> 
>>>> I would like to ask the question very differently. My question is not to ignore the importance of getting the definition correct for X3D <= V3.3.
>>>> 
>>>> 
>>>> Most (>95%) 3D modeling is done with a tool. In non-CAD environment, the tools is almost certainly Maya or Blender. Both of those tools have extrusions built in to their interface. I imagine CAD tools are similar. With so many tools providing graphical extrusion editors, and some of the tools being open-source (at least Blender);
>>>> 
>>>> Do we need an extrusion node in V4 to support content developed for V4+?
>>>> 
>>>> 
>>>> Leonard Daly
>>>> 
>>>> 
>>>> 
>>>> On 1/26/2016 7:15 AM, Alekseyev, Vsevolod (NIH/NIAID) [E] wrote:
>>>> Hi X3D community,
>>>> 
>>>> I've tried and failed twice to explain the problems with the definition of the Extrusion node. So here's a tl;dr version:
>>>> 
>>>> Dear authors of the X3D standard, please take a careful look at the standard and answer me:
>>>> 
>>>> 1) When the spine goes (0,0,0)-(0,-1,0), what is the CSP?
>>>> Note: all answers but one will render one of the reference models in the Savage archive invalid.
>>>> 
>>>> 2) When the spine goes (0,0,0)-(0,1,0)-(0,0,0), what is the CSP?
>>>> 
>>>> 3) When the spine goes (0,0,0)-(1,1,0)-(1,1,0)-(1,1,0)-(2,0,0), what is the CSP for the three middle points?
>>>> 
>>>> 
>>>> 
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>>>> 
>>>> --
>>>> Leonard Daly
>>>> 3D Systems & Cloud Consultant
>>>> X3D Co-Chair on Sabbatical
>>>> LA ACM SIGGRAPH Chair
>>>> President, Daly Realism - Creating the Future
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>>>> 
>>>> --
>>>> Leonard Daly
>>>> 3D Systems & Cloud Consultant
>>>> X3D Co-Chair on Sabbatical
>>>> LA ACM SIGGRAPH Chair
>>>> President, Daly Realism - Creating the Future
>>>> _______________________________________________
>>>> x3d-public mailing list
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> 