[X3D-Public] Does anyone export per-vertex normals?

Joe D Williams joedwil at earthlink.net
Thu Feb 10 17:46:38 PST 2011


http://www.hypermultimedia.com/Space/rocket/SHINY.WRL

was an old one I worked on. I also recommend understanding the X3D 
spec and realizing that any model that wants realism will bother to 
set the normals everywhere to the artist's preference and not be 
satisfied with automatic normal generation which can only handle a few 
of the several important visual cues and preferences. Notice that the 
bones in the skeleton at

http://www.hypermultimedia.com/x3d/JoeX3D/LaughingSkeleton.x3dv

look sort of featureless because of automatic normal generation. I 
will post links to a version with complete normals so we can see the 
difference, especially with lighting. Doesn't our favorite old tool 
from Keith give us normals if we set em?After normals, the next one to 
work on is bumpmapping.
Best Regards,
Joe

http://www.hypermultimedia.com/Space/rocket/ROCKET.WRL

http://www.hypermultimedia.com/Space/ROCKIT.WRL

http://www.hypermultimedia.com/Space/VBSTARS.WRL


----- Original Message ----- 
From: "Michalis Kamburelis" <michalis.kambi at gmail.com>
To: <dave at realmofconcepts.com>
Cc: <x3d-public at web3d.org>
Sent: Thursday, February 10, 2011 3:03 PM
Subject: Re: [X3D-Public] Does anyone export per-vertex normals?


> dave at realmofconcepts.com wrote:
>> I'm looking for examples of per-vertex normals on IFS's. Does 
>> anyone know
>> of a tool which export these?
>
> You can take a look at my old VRML 97 normals test in
> https://vrmlengine.svn.sourceforge.net/svnroot/vrmlengine/trunk/kambi_vrml_test_suite/vrml_2/normals.wrl
>
> But it was written by hand. At least Blender export scripts to VRML 
> 97
> and X3D don't generate explicit normal information, at least in the 
> last
> release.
>
>>Is there a documented algorithm for how this
>> should be done, especially regarding vertex splitting, smoothing, 
>> etc.?
>>
>
> The X3D specification about IndexedFaceSet is pretty clear about how 
> to
> set explicit normals: set non-NULL "normal" field, and optionally 
> set
> normalPerVertex, normalIndex. These allow various ways of providing
> normal vectors. The most flexible is when you use non-empty 
> normalIndex,
> then you have per-vertex normals and still the same vertex (the 
> "same"
> in Coordinate node) may have different normals depending on which 
> face
> it is on.
>
> It's up to the generator how such normals are generated... Maybe use
> something like creaseAngle, maybe use some information specific to 
> your
> generator (e.g. Blender could use "sharp edges" marks and EdgeSplit
> modifier information, in addition to AutoSmooth setting).
>
> Michalis
>
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