unfortunately the lighting model used in VRML is insufficient for the type
of catalogs you're talking about. To be able to specify lighting in lumens
requires an energy based lighting model.
However, specifying the vrml lighting equations in the spec. will allow
you to export a model lit using an energy based model to a vrml
browser. Without knowing the equations used for the lighting display,
you will gave no way of ensuring that what the user sees is what you
went to such pains to calculate.
Len Wanger -- [email protected]
Interactive Simulations Inc.
http://www.intsim.com/~isigen
On Sun, 14 May 1995, Scott Nelson wrote:
> >
> >- Materials and lighting: I agree strongly with Eric Haines that the
> >equations of the lighting model needs to be specified in the spec. This
> >is important to be able to specify detailed lighting. I understand that
> >many people want things that look roughly correct, but some or us to
> >through great pains to make sure lighting and look are accurate. For
> >instance, radiosity renderings go to great pains to calculate accurate
> >lighting. If browsers implement lighting differently, the walkthrough
> >will not accurately reflect the calculation.
> >
>
> I agree with the above statement with one further point:
>
> The local lighting value should be able to be interrogated.
> In lighting design (what my brother does for a living) there
> are specifications about the number of lumens that a work surface
> has to have. There are reams of these sorts of specs and they
> are very useful. I used some of the simpliest equations and specs
> when installing my track lighting system in my living room and
> ended up with a much better system than had I just guessed.
>
> Thus, a "lighting probe" could be used so that someone could
> ask about how much light was hitting some-such table surface,
> kitchen counter, desk, etc.
>
> There are also reams of specs about how much light the various
> bulbs put out. Thus, lighting models use calibrated sources
> (from a library of bulbs or fixtures) and you get
> calibrated results on all the surfaces. Then as a lighting
> designer, you just walk around the space with your "lighting
> probe" to make sure that everything is lit correctly. If not,
> just tweek the bulb.
>
> I see this as being a big-time real word use of VRML. Forget
> data gloves, spandex black suits, trampolenes, data feet,
> space registering IR systems. The simple calibrated bulbs would
> make anyone selling a VRML viewer lots of $$$. Or give away the
> viewer and just sell libraries of calibrated bulbs. Just like
> circuit modeling packages sell libraries of components. The
> base modeling code is farily generic, it's the fine tuned
> libraries that differentiate the packages. Does the marketing
> banta "razors and razor blades" come to mind???
>
> Just a few thoughts.
>
> Scott Nelson
>
>
> --
>
> +----------------------------------------------------+
> |Scott D. Nelson B131 Rm2074 3-1250 |
> |Lawrence Livermore National Laboratory |
> |7000 East Ave., L-153 Livermore CA 94550 |
> |email: [email protected] http://www-dsed.llnl.gov/ |
> +----------------------------------------------------+
>