[x3d-public] Extrusions, take 3

[doug sanden]

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
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X3D Co-Chair on Sabbatical
LA ACM SIGGRAPH Chair
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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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