[whatwg] <model/>: A 3D Equivalent to <img/>

[Brian Blakely]

Hi Simon,

These concerns are a part of this proposal, but if we collaborate without dissent, a file format can be chosen/devised, and browser vendors will implement the spec over time, and find different solutions to the same end, I am sure.

I see it as a case of the chicken or the egg.  If all these perpheral technologies existed, we likely would not be having this discussion because it would be a non-issue.

Mapping content onto the 3D media is a feature I have thought about also and do need desperately in my design work.  However, that is not appropriate for HTML to handle.

You'll probably find it in CSS, something to the tune of 'div { map-model: url(sphere.xml) stretch etc etc }' and associated properties.

Though this is a bit tangential to the goal of this proposal, a definition language for 3D models could define faces which are content mappable.  Speaking totally of-the-cuff for the sake of clarity:

<face id="content-face" etc etc />

..and in CSS:

map-model: url(cube.xml) content-face stretch etc etc;

-Brian

Simon Fraser wrote:

On Nov 2, 2009, at 4:26 PM, Brian Blakely wrote:



> * Though it does not have properties for clipping, Webkit's proposed

> implementation of 3D CSS does have them for perspective.  Clipping,

> lighting, texture stretching and additional considerations could also

> be a part of that spec, but those are discussions for the CSS WG.

>

> Without a 3D media element, none of that work can be done.



Implementing your proposal would require that the model and surrounding

CSS-transformed content be implemented via the same 3D engine, sharing

a common coordinate system. That vastly increases the burden placed on

an implementor of 3D transforms: suddenly wafers in space are non longer

sufficient, and you need a new engine with support for all the features

required by your <model /> content (which also needs to be specified  

somewhere).

You can't just glue a 3D-rendered model into an environment with  

CSS-3D-transformed

HTML elements and expect them to share a common 3D space.



> * This proposal of a model  can be considered a direct 3D analog to a

> PNG, and its height and width could certainly be modified in the X-Y

> axes on which 2D elements live, affecting document flow in that

> fashion.



A 3D analog for <img /> is a fine goal, but the primary issue is that  

there is

no 3D file format which is accepted as a standard for this kind of  

use. Even

if there were, the analogy breaks down because 3D is structured data;  

the author

wants to be able to address certain objects in the 3D scene in order to

animate them, or do click handling on them, or whatever. There is much  

more

complexity here than there is with images. In this sense, <model> is  

as much

a black box for 3D as WebGL on a <canvas> is.



A further issue with this proposal is that it doesn't address another  

request,

which is to integrate HTML content into a true 3D scene (e.g. a <div>  

mapped

onto a sphere, with operational hit testing etc).



> * Webkit's implementation of CSS does not remove 3D-ified elements

> from the document flow, the perspective of that flow is merely changed

> only for the affected elements.  3D and 2D elements can exist

> side-by-side that way as well.



Simon




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