[x3d-public] UnlitMaterial

[Andreas Plesch]

Yes, that is the overall idea and captured by the equations in the spec. In
addition, there are a few more considerations which UnlitMaterial covers as
carefully determined by Michalis.

-Andreas

On Fri, Feb 21, 2025 at 12:18 PM Joe D Williams <joedwil at earthlink.net>
wrote:

> Just logically, to me now anyway, if no light then all that is left is
> emissive.
>
> The shape can emit some kind of light (glow), according to transparency,
> but not reflect of absorb.
>
> So diffuse doesn't count for unlit because that is response due to effect
> of lighting.
>
> ?
>
> Joe.
>
>
>
>
>
> -----Original Message-----
> From: Extensible 3D (X3D) Graphics public discussion <x3d-public at web3d.org
> >
> Sent: Feb 20, 2025 2:23 PM
> To: X3D Graphics public mailing list <x3d-public at web3d.org>
> Cc: Andreas Plesch <andreasplesch at gmail.com>
> Subject: [x3d-public] UnlitMaterial
>
>
> Looking at UnlitMaterial:
>
>
> https://www.web3d.org/specifications/X3Dv4Draft/ISO-IEC19775-1v4.1-CD/Part01/components/lighting.html#LightingUnlit
>
> Can UnlitMaterial be thought of as Material without light contributions ?
> Eg. on_i for all lights is 0 ?
>
> It looks equivalent but perhaps there is a subtle difference. Yeah, one
> subtle difference appears to be that the transparency field is applied to
> diffuse.a rather than emissive.a .
>
> Related, the Phong lighting in the case of on_i all zero, does not seem to
> have a way to specify an alpha for emissive ? Not sure how much use
> emissive alpha has but UnlitMaterial has it.
>
> Thanks for any input, -Andreas
>
> --
> Andreas Plesch
> Waltham, MA 02453
>
>
>


-- 
Andreas Plesch
Waltham, MA 02453
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