Povray: what's it good for?

I was asked to give a talk on povray.  I got a question from the audience for
which I would love to have someone who is more artistically talented and more
computer-adept to give a short paragraph answer, an answer I could include in a
talk if I were ever to give one again.


You may know by now that I love using povray's abilities to make procedurally
generated things, and that stylistically I love shooting for the "left hump" of
the Uncanny Valley Curve.  (Using a quantum physics analogy, I'm sure I am
instead in a resonance tunneling state between the far left plains of the curve
and the UV itself, in my own artistic work.)

I showed them some of the images in the Hall of Fame, and gave them all great,
unconditional praise. Then I showed them some of my own animation work, and said
it was great fun. I explained about some of the HOF work involved using external
modelers.  Then came a question from the audience:


----
Q: "If you need to take meshes from an external modeler into povray, what
benefit is there over doing that instead of just rendering the image directly in
the external modeler?"
----

I said I didn't know. and might have mumbled the word radiosity. I said I liked
what the HOF guys did, and I liked having fun making my own things my way. (Not
that there's anything wrong with either.)  But what would you say is the best
technical answer to this question?   I'd love to have a paragraph I could just
paste into the next pres I ever make. I'm sure the answer is like, "Povray's
radiosity techniques are demonstrably better than ____ in ____ fashion." Again,
I'm not attacking povray, just want to make the full case of its power with
data.  (This is the sort of thing I was hoping for when I asked about "Speaker's
Notes" in p.g.)

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On 11/4/2011 8:45 AM, gregjohn wrote:
> ----
> Q: "If you need to take meshes from an external modeler into povray, what
> benefit is there over doing that instead of just rendering the image directly in
> the external modeler?"
> ----
>
> I said I didn't know. and might have mumbled the word radiosity. I said I liked
> what the HOF guys did, and I liked having fun making my own things my way. (Not
> that there's anything wrong with either.)  But what would you say is the best
> technical answer to this question?   I'd love to have a paragraph I could just
> paste into the next pres I ever make. I'm sure the answer is like, "Povray's
> radiosity techniques are demonstrably better than ____ in ____ fashion." Again,
> I'm not attacking povray, just want to make the full case of its power with
> data.  (This is the sort of thing I was hoping for when I asked about "Speaker's
> Notes" in p.g.)
>
Without even going into the radiosity, the obvious answer is, "If its 
something that you don't need a mesh for, or you can produce the same 
result, using math, the image will be more accurate, since it will be 
based on a physical model, rather than an approximation. Mesh can only, 
ever, be an approximation, and how good it looks depends entirely on how 
much detail you are willing to put into it, and *if* the computer can 
then handle it."

Hard to think of specific examples, except that something like a fractal 
would be a pain in the ass to produce "mesh", and trivial to do 
mathematically. However, even a sphere is simpler, and smaller, and more 
"precise", in POV-Ray. You need at least 64 triangles to make a "basic" 
sphere, and more and more, depending on how close the camera is, and how 
sloppy you want to allow the thing to be. In POV, a sphere is a sphere, 
in mesh, rendered on one of those fancy modellers, its a damn bloody 
stupid big mass of data your application, and the GPU, has to mess with. 
And, every triangle you have, the harder everything has to work to get 
anything out of it.

About as technical as I can get myself though. lol

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On 11/4/2011 8:45 AM, gregjohn wrote:
> Povray: what's it good for?

I can think of a few things that are behind why I use it:

1) You don't need to use meshes.  This is particularly useful with 
things like isosurfaces which give you a lot of power if you know how to 
use them well.

2) It has an easy human-readable input formation and doesn't require a 
UI.  This means that it's pretty simple to write a script in whatever 
language you like that outputs to POV and invokes the renderer 
automatically to generate a picture.  The ability to defined high-level 
objects directly (as opposed to just meshes) helps a lot here too.

3) It's a fantastic tool for getting a feel for the math behind 3D 
geometry.  The fact that you can easily use povray without a modeller 
give an incentive to learn how to design scenes well by hand, and in 
doing so you'll have to learn to think in 3D coordinates.  Obviously for 
professionals this doesn't really matter, but for people just starting 
out of graphics I think it can be a great thing.

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On 11/4/2011 8:45, gregjohn wrote:
> benefit is there over doing that instead of just rendering the image directly in
> the external modeler?"

Since POV-Ray supports more than just meshes (like isosurfaces, spheres, 
etc), it needs to have a much more powerful way of defining textures beyond 
just UV mapping a texture image. POV-Ray has the best texturing language 
I've ever seen, because every other tool expects your texturing language to 
be photoshop. While this is OK for some things (like characters, say), it 
tends to fall apart when you're talking about things like walls, floors, 
piles of rusty cubes, jumbled rocks on the beach, a forest full of 
randomly-generated trees, etc. POV-Ray's textures are the "infinite detail" 
of the modeling world.

-- 
Darren New, San Diego CA, USA (PST)
   People tell me I am the counter-example.

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> Q: "If you need to take meshes from an external modeler into povray, what
> benefit is there over doing that instead of just rendering the image directly in
> the external modeler?"

My main answer would be Kevin's nr 2. I use matlab a lot to generate the 
scripts (or at least the include files).

Secondary answers would be that
- the scripting language also allows automatic duplication of items and 
things like trace. All modellers nowadays come with a scripting tool 
that would allow you to do the same. It is less of an advantage nowadays.
- If you know the underlying language (e.g. python) than you're fine 
otherwise a language designed for defining 3D scenes is better than a 
general tool with all bells and whistles.
- The output looks much better than in the free 3D modellers, or at 
least it used to be so.
- Some of us are used to thinking algorithmically and don't like to play 
around with a mouse the whole day. Scripting also makes certain types of 
version control easier that point and click.
- Kevin nr 3. Give a man Blender to build a chandelier and he is busy 
for a day. Give him POV and he is busy for a day *and* he has finally 
understood the beauty of trigonometry.
- short code contest.
- the community

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> - Kevin nr 3. Give a man Blender to build a chandelier and he is busy
> for a day. Give him POV and he is busy for a day *and* he has finally
> understood the beauty of trigonometry.
> - short code contest.
> - the community

beatiful (and completely agree :o)

B Gimeno

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"gregjohn" <pte### [at] yahoocom> wrote:
> Povray: what's it good for?
>

Thanks for all the discussion.  But pretty much everyone is touting the beauty
of povray in "the way *I* use it". But no one really answered the question as to
the guy from the audience.  If you model something in 3DS or Blender, what is
the specific benefit of porting to povray?  "Best Renderer Evah!!!!!" is
probably the gist of the answer: I want details.

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POV-Ray can render curved surfaces which are ACTUALLY CURVED.

All those other modellers and renderers just *approximate* curves. In a 
normal renderer, a "sphere" is really a polygedron, with the lighting 
blurred a bit so that it looks smooth. (Unless you look at the profile. 
Or the shadow. Or where the shape intersects something else. Or...) When 
POV-Ray renders a sphere, it is perfectly spherical.

Fundamentally, representing a sphere as a mesh is WRONG. Granted, that's 
not a very rational argument. But to me, meshes just seem so stupid and 
unsophisticated. Mathematical perfection is so much more exciting...

-- 
http://blog.orphi.me.uk/
http://www.zazzle.com/MathematicalOrchid*

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On 6-11-2011 12:21, gregjohn wrote:
> "gregjohn"<pte### [at] yahoocom>  wrote:
>> Povray: what's it good for?
>>
>
> Thanks for all the discussion.  But pretty much everyone is touting the beauty
> of povray in "the way *I* use it". But no one really answered the question as to
> the guy from the audience.  If you model something in 3DS or Blender, what is
> the specific benefit of porting to povray?  "Best Renderer Evah!!!!!" is
> probably the gist of the answer: I want details.

That was not the question as you originally posted it. You can not blame 
us for answering the question you asked.

With respect to this new question: I think there is a mixed benefit/pay. 
Renderers might have functions tied in that are not easily ported to POV 
like e.g. hair. So if you use that sort of thing you should not port. 
OTOH even if I create a scene entirely in Blender I still port it to POV 
because I have more (and more intuitive) control over the final result, 
because of the way it handles cameras, textures and lighting. And for 
some reason I like the result better. Though Blender's renderer improved 
quite a lot over the last years. POV improved also but not as spectacular.

My answer to the question as you pose it now will probably be that in 
the majority of cases it is not a benefit to go from a mesh created in a 
modeller to POV. It is also a silly question. You already have beaten 
the solution in one particular (triangulated) shape and then go to a 
program where you might have have modelled them better and then ask: how 
can this program improve what I did wrong?

BTW that I think that there is not much point in porting a mesh to POV 
just to render it, in no way means that I think POV is outdated and has 
no role to play.
Two examples from other fields might illustrate that.
- Once there was something called BattleChess on the PC. The reason that 
it existed was because there was this other machine called an Amiga. 
Although it was technically possible to create the game on the PC, it 
needed the specific hardware and way of thinking on the Amiga to make 
people realize that.
- In the toolbox of a good programmer in the 80's were lex and yacc. 
They seem to be almost forgotten in this point and click WYSIWIG days of 
visual interfaces. Still, it makes sense to design a language for a 
specific field*. Simply because it allows you to focus on the things 
that are relevant.

Tools shape the way you think and solve problems. Using POV will improve 
your modelling even when using other programs.

*) at least until the time when the visual interfaces have made most 
people functionally illiterate.

-- 
Tools shape the way you think and solve problems. Using POV will improve 
your modelling even when using other programs.

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On 11/6/2011 3:21, gregjohn wrote:
> If you model something in 3DS or Blender, what is
> the specific benefit of porting to povray?

I did answer that. The texturing is likely better than what you get by 
hand-drawing a texture, for anything that has algorithmic textures (i.e., 
textures created by the environment, like rust or stone, rather than 
textures created by human design, like clothing).

I not uncommonly use pov-ray to create a flat texture that I then import 
into some other modeler to map onto a mesh. You could go the other way just 
as easily.

-- 
Darren New, San Diego CA, USA (PST)
   People tell me I am the counter-example.

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