[X3D-Public] Support for submeshes?
Keith Victor
keithrvictor at gmail.com
Tue Feb 5 13:52:07 PST 2013
Hello:
Way back in the day, Shout3D had such an extension in their Node Set.
They called it MultiMesh.
http://shout3d.net/shout3d_2.5_doc_dir/docs/nodes_reference/MultiMesh.html
( Looks like someone is still paying the bills at Shout3d! )
The basic idea is that they replaced the SFNode appearance field in the
Shape node with a MFNode field ( appearences ), which is a LIST of
appearance nodes, rather than a single Appearance node.
Then, the Geometry node would have an additional field: MFInt32,
appearanceIndex. Which assigns an appearance Index for each TRIANGLE. ( or
face )
That general approach was a bit messy. I would have preferred that they
specify the transition between the appearances, so it forces the author to
place all the triangles ( or Faces ) that share the same appearance to be
next to eachother. ( so the renderer does not have to do so )
So, we would have:
MultiAppearanceShape
{
SFNode geometry
MFNode appearances
}
AND
AdditionalfieldOnGeometryNode:
MFInt32 appearanceIndex ( index of appearance node Per Face )
or
MFInt32 appearanceTransition (index of the Face where we transition to the
next appearance )
Keith Victor
On Tue, Feb 5, 2013 at 1:31 PM, Richard F. Puk <puk at igraphics.com> wrote:
> Hi, Tony and Dave –****
>
> ** **
>
> How about someone proposing such a node so that its specific
> characteristics can be evaluated? Everyone knows what a submesh is but how
> to fit it in cleanly in the X3D architecture is somewhat open. Please
> provide a proposed node definition.****
>
> ** **
>
> **n **Dick****
>
> ** **
>
> /**********************************************
>
> | Richard F. Puk, Ph.D., President****
>
> | Intelligraphics Incorporated****
>
> | 7644 Cortina Court****
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> | Carlsbad, CA 92009-8206****
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> | Email: puk at igraphics.com****
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> \****************************************** ****
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> ** **
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> ** **
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> ** **
>
> *From:* X3D-Public [mailto:x3d-public-bounces at web3d.org] *On Behalf Of *Tony
> Parisi
> *Sent:* Tuesday, February 5, 2013 9:26 AM
> *To:* Dave A
> *Cc:* x3d public mailing list
> *Subject:* Re: [X3D-Public] Support for submeshes?****
>
> ** **
>
> Yeah it's been that way for 2 decades now. Would be nice to have submesh
> materials, all modern tools and rendering systems have them.****
>
> On Tue, Feb 5, 2013 at 9:01 AM, Dave A <dave at realmofconcepts.com> wrote:**
> **
>
> So, this means that no X3D player could really understand the modern(?)
> concept of a mesh with several materials (actually, modelling programs been
> making them for a long time, was something I faced on the Max to X3D
> exporter).
>
> I think it's time for a new node to be added to the spec!
>
> Dave A.****
>
>
>
> ****
>
> On 2/4/2013 10:46 PM, Tony Parisi wrote:****
>
> Multiple Shape nodes wouldn't work: that implies multiple meshes (vs. a
> single mesh with multiple materials). Yes, you end up sharing vertices but
> the semantic is totally different.
>
> Tony****
>
> On Mon, Feb 4, 2013 at 9:22 AM, Dave A <dave at realmofconcepts.com> wrote:**
> **
>
> Thanks, but again, this is for Interchange, not so much Runtime.
> Maybe a proto would be best, assuming the reader can do protos.
> Actually, I'll just store META data to aid translation.
> I still think a new Node type would be better.
> Also, for interchange, a more semantic way to specify simple shader types
> like Bump, Bump Specular, etc. would be great. Otherwise, the reader needs
> to do some AI to figure out what the intent was.
>
> Cheers
>
> Dave A ****
>
> ** **
>
> On 2/3/2013 11:13 PM, Cecile Muller wrote:****
>
> Hi Dave, ****
>
> ** **
>
> ** **
>
> Your second idea is indeed correct: DEF the Coordinate node in the first
> Shape and USE it ****
>
> in the other Shape, that way you can have a difference Appearance for each
> submesh.****
>
> ** **
>
> ** **
>
> For example:****
>
> ** **
>
> #X3D V3.0 utf8****
>
> ** **
>
> Shape {****
>
> appearance Appearance {****
>
> material Material {****
>
> emissiveColor 0 1 0****
>
> }****
>
> }****
>
> geometry IndexedFaceSet {****
>
> coord DEF all_coord Coordinate {****
>
> point [-1 0 0, 0 0 0, 1 0 0, 0 1 0]****
>
> }****
>
> coordIndex [0 1 3 0 -1]****
>
> }****
>
> }****
>
> ** **
>
> Shape {****
>
> appearance Appearance {****
>
> material Material {****
>
> emissiveColor 0 0 1****
>
> }****
>
> }****
>
> geometry IndexedFaceSet {****
>
> coord USE all_coord****
>
> coordIndex [1 2 3 1 -1]****
>
> }****
>
> }****
>
> ** **
>
> ** **
>
> If it's cumbersome, you could have a Script that creates the Shape nodes**
> **
>
> wrapped in a PROTO to have a more friendly interface.****
>
> ** **
>
> ** **
>
> See you,****
>
> Cecile****
>
> ** **
>
> 2013/2/1 Dave A <dave at realmofconcepts.com>****
>
> Hey all,
>
> Been a while since I parsed the spec, but is there support for submeshes?
> You know, where one set of vertices is shared by different poly or
> triangle lists, and each of those lists
> corresponds to a different Appearance?
>
> Or would I have to create a Group under which I would put Shapes, with the
> first Shape's geometry containing the coordinate list (and first submesh's
> indices),
> then subsequent Shapes would USE that coordinate list, providing their own
> indices (and Appearances of course)?
>
> Cheers
>
> Dave A.****
>
> ** **
>
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>
> --
> Tony Parisi tparisi at gmail.com
> CTO at Large 415.902.8002
> Skype auradeluxe
> Follow me on Twitter! http://twitter.com/auradeluxe
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>
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> ** **
>
>
>
>
> --
> Tony Parisi tparisi at gmail.com
> CTO at Large 415.902.8002
> Skype auradeluxe
> Follow me on Twitter! http://twitter.com/auradeluxe
> Read my blog at http://www.tonyparisi.com/
>
> Read my book! *WebGL, Up and Running*
> http://shop.oreilly.com/product/0636920024729.do
> http://www.amazon.com/dp/144932357X****
>
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