[x3d-public] lights in switch nodes

[GPU Group]

I found Blender wraps DirectionalLight in a Transform when exporting X3D..
In freewrl DirectionalLight applies to siblings and lower. So the blender
light doesn't show. But I found that was handy for Inlining a blender
scene, and applying the lights I wanted in the parent scene.
http://dug9.users.sourceforge.net/web3d/sunpath/SunPath.x3d
Also seens to work in X_ITE.
http://dug9.users.sourceforge.net/web3d/sunpath/SunPath.html
-Doug

On Fri, May 11, 2018 at 2:01 PM, Leonard Daly <Leonard.Daly at realism.com>
wrote:

> Andreas,
>
> The spec text that only the selected child of a Switch is traversed. It
> doesn't explicitly state it, but I presume that means is rendered (or at
> least considered for rendering). All children of a Switch participate in
> event handling (sending and receiving, including state changes).
>
> At one time (~20 years ago), lighting was expensive and limited to 8
> lights. Light scoping was limited so the scene could be rendered. I have
> not really seen scoped lights in quite a while. I think it is possible, but
> you need to go to extra work to make it happen. Unfortunately, X3D (spec)
> has not kept pace with the rest of the graphics community on lighting,
> while many of the applications have.
>
> I would not consider it good practice to include lights as an indirect
> child because they can have an impact beyond the limit of the node.
>
>
> Leonard Daly
>
>
>
> Children of switch nodes still participate in all events; however the
>
> Since lights are child nodes, they can occur as children of switch nodes.
>
> Presumably that means that only light nodes which are traversed in the
> switch are active and should be used for illumination. Others occuring
> in the switch should be turned off. Is that the intended behaviour ?
>
> I am asking because switch is mostly used with Shape nodes, and x3dom
> currently uses all lights whereever they occur.
>
> Thanks, Andreas
>
>
>
> --
> *Leonard Daly*
> 3D Systems & Cloud Consultant
> LA ACM SIGGRAPH Past Chair
> President, Daly Realism - *Creating the Future*
>
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>
>
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