Chambers <ben### [at] pacificwebguycom> wrote:
> Look at it another way.

> If there were a feature that made boxes look a *lot* better by
> performing lighting calculations differently, would you advocate it?

  That comparison is very poor.

  Triangle meshes are by far the most common rendering primitive in
computer graphics. Basically all renderers and modellers support them,
and in fact there are lots and lots of renderers and modellers which
don't support anything else. Even when they do support something else,
eg. NURBS, they tend to be primitives which are very easily tesselable.

  If you search for models out there, they will invariably be in triangle
mesh format. Search for entire scenes out there which you can render, and
they will invariably be in triangle mesh format (or easily conversible to
one). Basically you can create entire scenes with triangle meshes, and most
people do. In other words almost anything can be (and is) done with meshes.

  A box is in no way so versatile all on its own. You can't use boxes only
in order to seriously create any scene.

  It makes a lot of sense to add enhancing features which work on meshes
only, for the exact reason that meshes are so versatile and common.

  And it's not like there would be no precedent. For example, even though
UV-mapping cannot be applied to all POV-Ray primitives, that didn't stop
people from implementing it in POV-Ray.

-- 
                                                          - Warp

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andrel <a_l### [at] hotmailcom> wrote:
> The SDL is only relevant in the sense that if you would allow a version
> of POV with only triangles, effectively stripping all other primitives,
> it would not really be POV anymore.

Well, some of the statements describing primitives could be modified to instead
create mesh representations of them.

Anyway, you're right in that POV-ray wouldn't be POV-ray anymore if it were
stripped down to meshes - at least if I'm asked.

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Warp <war### [at] tagpovrayorg> wrote:
>   It makes a lot of sense to add enhancing features which work on meshes
> only, for the exact reason that meshes are so versatile and common.
>
>   And it's not like there would be no precedent. For example, even though
> UV-mapping cannot be applied to all POV-Ray primitives, that didn't stop
> people from implementing it in POV-Ray.

It's a big difference whether you (a) add some feature that will enhance
usability of meshes and don't reduce the usability of others, or (b) introduce
a lighting model that cannot be used unless your scene is meshes only.

There's no problem adding a UV-map to some mesh in any existing scene.

There *would* be a problem adding a better but meshes-only lighting model to an
existing scene.

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> -----Original Message-----
> From: Warp [mailto:war### [at] tagpovrayorg]
> Posted At: Saturday, December 27, 2008 2:24 PM
> Posted To: povray.beta-test
> Conversation: Radiosity: status & SMP idea
> Subject: Re: Radiosity: status & SMP idea
> 
> Chambers <ben### [at] pacificwebguycom> wrote:
> > Look at it another way.
> 
> > If there were a feature that made boxes look a *lot* better by
> > performing lighting calculations differently, would you advocate it?
> 
>   That comparison is very poor.

I don't think so.  You're talking about a new lighting model, something
that drastically effects the final image.  If such a lighting model is
usable with only one type of primitive, then any scenes wishing to use
it will be forced to use only that primitive.

In other words, I would be forced to use only meshes if I want the new
lighting model.

>   If you search for models out there, they will invariably be in
> triangle mesh format.

When made by other programs, that is.

Search for items made in POV, and triangle meshes are rather uncommon.

>   A box is in no way so versatile all on its own. You can't use boxes
> only in order to seriously create any scene.

Sure you could, if the tools were written to generate boxes instead of
triangles.  It wouldn't even be that much harder.

Most people modeling don't actually work with triangles; it's just the
tool breaks down what the user does into triangles, and then works with
those.  The same effect *could* be achieved with boxes.

>   It makes a lot of sense to add enhancing features which work on
> meshes only, for the exact reason that meshes are so versatile and
common.

Fine, I agree that meshes are common... in other modelers.

>   And it's not like there would be no precedent. For example, even
> though UV-mapping cannot be applied to all POV-Ray primitives, that
didn't
> stop people from implementing it in POV-Ray.

That's because if I use UV-mapping, I'm not prohibited from using a
sphere right next to the mesh.  If the lighting model is different for
the two objects, however, I would be (unless I were trying to achieve a
discrepancy between the two).

If it were something as trivial as UV mapping, I'd say go for it.  But
for something as *global* as the lighting model, I think it needs to
apply to all POV primitives for it to be workable.

...Ben Chambers
www.pacificwebguy.com

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clipka <nomail@nomail> wrote:
> It's a big difference whether you (a) add some feature that will enhance
> usability of meshes and don't reduce the usability of others, or (b) introduce
> a lighting model that cannot be used unless your scene is meshes only.

  What do you mean "cannot be used"? Of course it can be used even if your
scene contains something else than meshes. It's just that the radiosity
lighting is limited to appear on the meshes. The other primitive will have
to do with regular lighting.

-- 
                                                          - Warp

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Chambers <ben### [at] pacificwebguycom> wrote:
> I don't think so.  You're talking about a new lighting model, something
> that drastically effects the final image.

  You mean UV-mapping doesn't drastically effect the final image?

>  If such a lighting model is
> usable with only one type of primitive, then any scenes wishing to use
> it will be forced to use only that primitive.

  What do you mean "forced to use only that primitive"? What would force
them to do so? I don't see any reason why other primitives couldn't be
used as well. It's just that the radiosity will not be calculated for the
other primitives, but I see no reason why they cannot be used. It's simply
that the other primitives will have to be illuminated by conventional means.

  And besides, so what if the radiosity only affects meshes? As I said,
creating entire scenes with meshes is completely normal, and in most
renderers the *only* thing they support. If you download free objects or
entire scenes out there, made with some modeller, guess which format they
use.

> In other words, I would be forced to use only meshes if I want the new
> lighting model.

  1) Who forces you?

  2) So what? You could say the same about UV-mapping. Does that bother you?

> >   If you search for models out there, they will invariably be in
> > triangle mesh format.

> When made by other programs, that is.

> Search for items made in POV, and triangle meshes are rather uncommon.

  Guess how many objects/scenes out there can you find which are made
in other programs, compared to how many of them will be made with POV-Ray.

> >   A box is in no way so versatile all on its own. You can't use boxes
> > only in order to seriously create any scene.

> Sure you could, if the tools were written to generate boxes instead of
> triangles.  It wouldn't even be that much harder.

  Now you are nitpicking, and you know it.

> >   And it's not like there would be no precedent. For example, even
> > though UV-mapping cannot be applied to all POV-Ray primitives, that
> didn't
> > stop people from implementing it in POV-Ray.

> That's because if I use UV-mapping, I'm not prohibited from using a
> sphere right next to the mesh.

  And what exactly what prohibit you from using a sphere right next to
the mesh if radiosity was used?

> If it were something as trivial as UV mapping, I'd say go for it.  But
> for something as *global* as the lighting model, I think it needs to
> apply to all POV primitives for it to be workable.

  So because radiosity can only be applied to meshes, we must not offer
this tool to anyone who could find it useful.

  I'm sorry, but that's just stupid.

-- 
                                                          - Warp

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Warp wrote:
>   And what exactly what prohibit you from using a sphere right next to
> the mesh if radiosity was used?

The image will look horrible if each object is rendered with different
lighting.

Would the sphere reflect diffuse light to the mesh?

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Nicolas Alvarez <nic### [at] gmailcom> wrote:
> The image will look horrible if each object is rendered with different
> lighting.

  If you want the sphere to have the same lighting as the mesh, then use
a mesh instead of a sphere.

  It's not like this would be the only primitive-specific feature in POV-Ray.
Not being able to implement some feature for all primitives has never stopped
anyone from implementing them for specific primitives anyways.

-- 
                                                          - Warp

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Warp <war### [at] tagpovrayorg> wrote:
>   What do you mean "cannot be used"? Of course it can be used even if your
> scene contains something else than meshes. It's just that the radiosity
> lighting is limited to appear on the meshes. The other primitive will have
> to do with regular lighting.

.... and that will probably look crappy, unless you're actually aiming at this
type of effect.

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> -----Original Message-----
> From: Warp [mailto:war### [at] tagpovrayorg]
> Posted At: Sunday, December 28, 2008 10:37 AM
> Posted To: povray.beta-test
> Conversation: Radiosity: status & SMP idea
> Subject: Re: Radiosity: status & SMP idea
> 
> Nicolas Alvarez <nic### [at] gmailcom> wrote:
> > The image will look horrible if each object is rendered with
> different
> > lighting.
> 
>   If you want the sphere to have the same lighting as the mesh, then
> use
> a mesh instead of a sphere.

Warp, that statement makes my point.

I think we're operating under different assumptions here.  I'm under the
impression that a scene would look best when the entire scene uses the
same lighting model.

You're saying that different parts of the scene can use different
lighting models.

While technically you are correct, the results do *not* look good.
Remember those 80s movies, where you would have a scene shot with one
light, and an actor filmed separately in different lighting conditions,
and the actor was superimposed onto the scene?  Remember how fake and
horrible it looked?

Now, if you're *trying* to make a scene that looks fake and horrible,
then by all means go ahead.  Most of us here don't want that.

And as far as triangle meshes go, I think it would be a good thing for
POV to support them (it currently doesn't, you know, unless you run it
through a converter anyway), BUT they should fit in the scene... meaning
they need the same texturing & lighting models that the rest of POV
uses.

...Ben Chambers
www.pacificwebguy.com

A render isn't slow unless it won't finish until after your next
birthday.

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