"Alex" <ale### [at] quadcomar> wrote in message
news:web.41b89f2a17a60fa48c2d45480@news.povray.org...
> I'm running out of ideas on how to making it more photo-realistic, I think
> the blurred reflection would give it a very nice touch, I'll start
> experimenting with that... now about the darkness, it looked fine on my
> monitor, but then I notice it's too dark here at the office, I just don't
> know where to start:
>
> 1. using more brightness at the radiosity
> 2. giving textures more ambient
> 3. using lighter colors.
> 4. adding more lights
>
> I think any of those would make the image brighter.. but I'm not sure
which
> is best, or maybe it's a good ballance of them all... well, as long as it
> looks ok I think it doesn't really matter how do you achieve the goal,
> right?
>
> thanks for the feedback I'll keep working on it, and keep listening to
tips
> & hints, I'll repost more screens when I get better results.

Regarding the brightness - it looks perfect on my monitors (which have been
custom ICC profiled); viewing a histogram of the image shows a good spread
of luminance as well, so if it looks strangely dark on your work monitor,
it's due to your work monitor being poorly calibrated (not enough
brightness, not enough contrast, etc).

You can adjust the scene's gamma manually, but normally this isn't required
unless you're specifically creating the image to be displayed on another
platform (e.g. if you're on a Mac and are designing for display on a PC).
Check out 3.2.4 Global Settings in the help file - specifically the
assumed_gamma and display_gamma settings - for more information on this.

But like I said, if I were you I'd leave it as it is, because it looks fine
here.

Lance.

thezone - thezone.firewave.com.au
thehandle - www.thehandle.com

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> if I were you I'd leave it as it is, because it
> looks fine here.

I like my images to look good on every monitor out there. Personally I
think, better too bright than too dark. That way, everyone will be able to
see it, and usually I don't notice when images are "too bright". Anyway
it's usually possible to find a "perfect" balance, but that's not just a
matter of gamma-correction. Gamma correction is important but cannot fix a
rendering that isn't built with consideration of contrasts.

My guess is, the histogram shows a good spread of luminance because the blue
ground statistically covers up for the lack of contrast in the speaker.

It's tricky to achieve good looking, black materials, even more so in
computer renderings. But a good starting point would be to find some
reference photos of black things (possibly speakers) and work from there.

Alex suggested "using more brightness at the radiosity, giving textures more
ambient, using lighter colors, or adding more lights". I wouldn't do that,
except perhaps "adding more lights" but they should to be carefully
positioned. There are many approches to it, but here is my suggestion:

Turn off radiosity. You can activate it again later, but it's not strictly
needed. For an image of this kind of complexity (where there is only one,
or maybe a few objects in focus, in an empty room) you can usually fake the
radiosity without too much trouble. Doing so gives you even greater control
over contrast and highlights. But even if you decide to turn on radiosity
again, it's a good idea to first position your light_sources, and ensure
they work well.

There are many interesting things you can do with just the light. I won't go
into details here but you decide the mood of the image with light. For
example you can make it look "intense", "warm", "cold", or "natural". But I
assume that for now you'd like people to concentrate on the speaker itself,
when they see your image. You'd like to draw peoples attention to the
design and modelling of the speaker, rather than the enviroment.

So let's use something alone the lines of a "three point lighting system".
You can read lots about it, various places on the Internet, but here is a
simple approch:

The first light you set up, should be the strongest (brightest). This is
called the "key light". I suggest you position it to the left of the
speaker, let's say about 3 meters away. That should be well outside the
camera view. Then you can experiment a little, by moving the light in the Z
direction until you think the shadows from the speaker have a nice
"shape"... I would suggest moving the key-light in the direction *towards*
the camera, so it shines on the front of the speaker, still to the left...
The code should look something like this:

light_source { Position, Colour
    fade_distance 1 fade_power 2
    area_light { 3*x, 3*z, 4,4  circular orient }

I haven't tested but I hope it works. As you can see, I made it a spherical
area_light because I think, a soft shadow would be most flattering to the
speaker... You can adjust the softness to your liking. But fade_distance &
fade_power is best left alone... The colour should be white (or whatever
you desire) but you will need a value that goes well beyond 1.0. Try 50,
100, or more. This is due to the realistic fading I activated.

By the way, if you haven't done so already I suggest you add this line to
the top of your scene: global_settings { assumed_gamma 1 }

On my computer (and I assume lots of other standard PC's with a standard
installation of POV-Ray) this will result in images that use a standard 2.2
gamma correction. If you don't add this line, your rendering will probably
not use gamma correction at all !  Well, it's a long and confusing story.
But lets leave it at this.

Now, after specifying the assumed_gamma, you will probably have to adjust
the blue ground and the black materials, well ALL your materials, but it's
worth it. Another thing that is quite important, is that you should use
"ambient 0" in all your finish statements. Because you don't want the
speaker to EMIT light. Ambience is an old feature from the time when
computer were much slower. Today the feature is rarely used except for
objects that we want to EMIT light.

Back to the key-light: When you are satisfied with the position of your
key-light, the shadows it produces, and the intensity of the light - it is
time to turn it off temporarely, and start adding a so-called "fill light"
or two.

Basically you are using the same procedures as above, but position the
fill-light to the right of the speaker (opposing the key-light). Make it
more dim, and with much softer shadows. Try to make it look like, you're in
a room only lit by a large window, late in the evening. In such a room,
there are no highlights, just soft, dim light that bounces around the
walls. This is the mood you're after. Eventually you can add a colour to
the fill-light ..brown or blue.

When you are satisfied with the fill-light, turn on the key-light again and
see if they both work well together... Still satisfied? Good.

Now, it's time to fake the radiosity by adding another fill-light. But this
one will be placed beneath the ground, and in front of the speaker, so it
will give the impression that light is bouncing from the ground, up onto
the speaker. To achieve this effect (having a light_source beneath the
ground, without being blocked by the ground) you need to use a "light
group". It's very simple. You want the speaker and the ground-light wrapped
into a "light group like this:

light_group {
   Speaker_Object
   Ground_Light
}

Again you can adjust the intensity of the ground-light, the colour and the
soft shadows to your liking. If the ground is blue (as in the image you
posted earlier) I suggest you make the ground-light blue. Don't hesitate to
experiment with the position of the ground-light...

Well, I would be interested in seeing the rendering after this. There are
still a few things to do, but I realise this post is already too long and
I'll stop writing now... I hope you can use it somehow, for inspiration, at
least.

Regards,
Hugo

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Wow! I'm impressed by the suggestions! this newsgroup is so friendly! I
haven't seen such a collaborative community in a long time, I'll work on it
this weekend and let you all know how it went, posting new renders when I'm
done.. I've been trying the blurred reflections, now I'll try the lights
and all those hints hugo sent.. thanks a LOT !!

Alex Verstraeten.

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Hugo Asm" <nomail@nomail> wrote in message
news:web.41b99b1d17a60fa4ba17f4dc0@news.povray.org...> > if I were you I'd
leave it as it is, because it
> > looks fine here.
>
> I like my images to look good on every monitor out there.

Which, as you'd already know, isn't possible - if someone has the brightness
turned right down, good luck seeing all of the nice shadow detail you put
in.  If they have it turned all the way up, the image is going to look
washed out.  That's why the safest bet if you want it to look good on a
range of monitors is to make it look good when viewed on a monitor with a
2.2 gamma response curve.  This is why my LCDs are calibrated using a
colorimeter to match a gamma of 2.2, which is why I was saying leave it as
it is - if it looks good on my monitor, which is set up to match a gamma of
2.2, then it should look good on "most" monitors that don't have their
calibration way out of whack.

Then again, most people have their monitors set to whitepoint of 9300 kelvin
*groan*.

> My guess is, the histogram shows a good spread of luminance because the
blue
> ground statistically covers up for the lack of contrast in the speaker.

I was talking about *just* the speaker - there's good luminance range even
when excluding all areas of the blue backdrop, in fact from 0% to nearly
100% (around 250/255 - i.e. ~98% luminance).

> It's tricky to achieve good looking, black materials, even more so in
> computer renderings. But a good starting point would be to find some
> reference photos of black things (possibly speakers) and work from there.

But his speaker cabinet isn't supposed to be black - I'd imagine, like most
Sony speaker units, it's probably "midnight grey".  At least my Sony
speakers are like that.  So, they shouldn't appear black (like the speaker
cones should, and do).

In my opinion, Alex's image already has very good contrast, and in this case
I think leaving radiosity on is a good idea - the cabinet is picking up a
subtle blue tint, and the area around the cabinet (e.g. at the front bottom
of the cabinet) is picking up a subtle grey tint.  Removing radiosity would
lose this subtly and make the image not seem as realistic (as our brains
will subconsciously pick up on these missing cues and tell us something is
"wrong").

Lance.

thezone - thezone.firewave.com.au
thehandle - www.thehandle.com

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well, well... I made some progress since my last shot, I wasn't going to
post until I had something decent, but I got all excited and couldn't
resist :)

I added a few more details to the speaker, tuned all the textures, set
assumed_gamma to 1.0, put some area lights, remove radiosity, tweaked the
fade values of lights, and suddenly this image appeared on my screen. Hehe
it's way too bright with fancy contrast.

but there's something about the image texture that looks nice, it's almost
black & white, grainy and overburned. you can see all the details in it

you know, it's nice to play with lights without radiosity, it gives me more
control over the look of the image... once I get something nice without
radiosity, I'll start playing with it.. but for now I like the way it's
going...

still no luck with blurred reflections, it took a lot of time to render and
it didn't look metallic :(

woops, I forgot to set the sticker's final settings. it's pure black.

thank you all for the suggestions, it really helped.

I'll keep posting later...

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Attachments:
Download 'testing sony no radiosity gamma 1.png' (334 KB)

Preview of image 'testing sony no radiosity gamma 1.png'

Hi Lance,

Perhaps you can clarify something for me: When you say, your LCD is
calibrated with a 2.2 gamma response curve, does that mean your
software/hardware adjusts the gamma automatically? If so, you do not
represent the majority of people who, like myself, uses a system that does
not feature automatic gamma correction, and therefore needs pictures that
have the gamma correction "built in".

I know it isn't possible for my images to look good on all monitors but I
try to accomodate most people.

> I was talking about *just* the speaker -
> there's good luminance range even when
> excluding all areas of the blue backdrop,
> in fact from 0% to nearly 100%
>(around 250/255 - i.e. ~98% luminance).

If you say so. I believe you, but it still doesn't look good here. And most
professional work DO look good on my monitor, so I assume this image has a
way to go. Besides there is a difference between histograms and "the minds
eye". Maybe that is part of the reason. I have distinct ideas about, what
this speaker could look like, and should look like, in a good lighting
enviroment.

> Removing radiosity would lose this subtly
> and make the image not seem as realistic

Yes, true. I've had much fun playing with radiosity, and with scenes that
are solely lit by radiosity, so they behave more like the real world. But
sooner or later we always run into the barrier of extremely slow renders,
and we realise that even those renderings are miles away from complexity of
the real world. Even if the light bounces around correctly, it doesn't
respond well to our faked and always very simplistic textures / materials.

So I encourage people to try and achieve good lighting conditions with
oldfashioned pointlights / spotlights, because it teaches us some important
lessons. If a scene looks great without radiosity, it means we have done a
good job setting up light, and radiosity will add the final touch. On the
other hand, if we have done a poor job setting up light, radiosity will not
help much.

It has come to my knowledge that lots of professional work today does not
use radiosity, or any other kind of advanced algoritm for solving
global-illumination... In movies, G.I. are often faked with fill-lights or
painted into the bitmap textures (eventually baked into them). For example,
there is a new movie out called "Troi". I haven't seen it, but I have read
about the CG sequences of the city Troi and some battles on the fields. It
looks pretty realistic but does not use G.I.! The artists explain that G.I.
would have been impractical. For one thing, it would have been much slower,
but even the large studios and render-farms run into problems with memory
capacity, and even the most expensive render-engines cannot always handle
an animation without G.I. artifacts. (They should've used POV-Ray instead,
hehe... well)

I don't discourage the use of G.I. either! Especially in complex indoor
enviroments with walls, and detailed objects with many holes and creases
where the light creeps in, radiosity is certainly the best solution. And in
still-images it's often not much of a speed issue, provided it's used in
conjunction with pointlights. But radiosity is only an aid; it does not
replace the need for good, manual lighting.

Regards,
Hugo

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Hi,

> I made some progress since my last shot

You certainly did!  :-)  You're right it's too bright for a "black" cabinet
but I must say, I like it anyway.

> still no luck with blurred reflections,
> it took a lot of time to render and
> it didn't look metallic :(

Some metal gives clean and sharp reflections. This isn't unrealistic. But
it's difficult to guide you in any direction when I don't know what "look"
you're after...

> woops, I forgot to set the sticker's
> final settings. it's pure black.

Reminds me of a glassy material. Adds nice contrast. Looks good! By the way,
this rendering suffers a little from low-quality Anti-Alias. Are you going
to bump-up the settings for the next render?

For example:  +AM2 +A0.1 +R2 -J

Or if you want perfection that will guarantee smooth, thin lines: +AM2 +A0.0
+R2 -J


Regards,
Hugo

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"Hugo Asm" <nomail@nomail> wrote in message
news:web.41bcd27917a60fa4ba17f4dc0@news.povray.org...
> Hi Lance,
>
> Perhaps you can clarify something for me: When you say, your LCD is
> calibrated with a 2.2 gamma response curve, does that mean your
> software/hardware adjusts the gamma automatically? If so, you do not
> represent the majority of people who, like myself, uses a system that does
> not feature automatic gamma correction, and therefore needs pictures that
> have the gamma correction "built in".


Hi Hugo, no it doesn't happen automatically.  Because LCDs have nothing like
a 2.2 gamma curve (in fact, the curve is somewhat S-shaped), trying to do
any kind of graphic design or print media work on an uncalibrated LCD causes
all kinds of problems - the result is nothing like it should be.  So the
LCDs need to have ICC profiles generated for them specifically (since even
two LCDs/CRTs of the same brand are different in their response curve out of
the box, and especially in the case of LCDs, tend to have a green/blue
colour cast on black).  Because I have two LCDs this is even more important,
as you want something on one monitor to look the same as it does on the
other monitor.  So I use a GretagMacbeth colorimeter (the i1 model) to
measure the LCDs.  It's a two step process of first configuring the LCDs
using the colorimeter to ensure the whitepoint is correct, the
brightness/contrast settings are optimal, and the individual RGB channels
are as close as possible to even.  This is done by having the colorimeter
measure the output of a 100% white screen while you adjust the RGB controls,
etc, until they're within certain ranges that the software displays.  Then
you let the colorimeter measure the LCDs (it does this by showing panes of
various colours and measuring the results) and then generating appropriate
ICC profiles.  These profiles are then loaded when Windows starts and they
affect the output at the video card level to compensate for whatever cast
the LCDs have.  This means that you end up with LCDs that don't have a
colour cast and which match each other, and that are set for whatever
whitepoint you're designing for (6500K in my case - a "neutral" white,
rather than the cool/cold white that most monitors are set for by default).
And, you end up with a response curve that emulates a standard 2.2 gamma CRT
(or whatever gamma you want to replicate).

So basically it doesn't automatically adjust, I have to get out the
colorimeter and profile them - the idea is simply to convert LCDs that have
very non-standard response curves (when compared to CRTs) to act like an
average 2.2 gamma CRT (while also removing any colour casts and
irregularities in the different colour channels).

It really makes a huge difference when you can print something and it comes
out identical to what you have on screen (of course, you need to profile the
output device as well for this to work - that's another story in itself),
and to know that what you're designing on screen will also look right on the
majority of average CRT monitors.

> I know it isn't possible for my images to look good on all monitors but I
> try to accomodate most people.

Yup.

> > I was talking about *just* the speaker -
> > there's good luminance range even when
> > excluding all areas of the blue backdrop,
> > in fact from 0% to nearly 100%
> >(around 250/255 - i.e. ~98% luminance).
>
> If you say so. I believe you, but it still doesn't look good here. And
most
> professional work DO look good on my monitor, so I assume this image has a
> way to go. Besides there is a difference between histograms and "the minds
> eye". Maybe that is part of the reason. I have distinct ideas about, what
> this speaker could look like, and should look like, in a good lighting
> enviroment.

I agree - but the image looked "right" to me  - it looks exactly like my
Sony speakers do.  I was only looking at a histogram to see if there was a
particular reason why it might not be looking very good on Alex's work
monitor - I don't make a habit of looking at histograms unless I'm doing
colour correction work or matching a series of photos to each other :)
(although Photoshop's new Histogram flyout can be quite handy as it always
performs a histogram on the current selection and shows each channel
separately)

> > Removing radiosity would lose this subtly
> > and make the image not seem as realistic
>
> Yes, true. I've had much fun playing with radiosity, and with scenes that
> are solely lit by radiosity, so they behave more like the real world. But
> sooner or later we always run into the barrier of extremely slow renders,
> and we realise that even those renderings are miles away from complexity
of
> the real world. Even if the light bounces around correctly, it doesn't
> respond well to our faked and always very simplistic textures / materials.
>
> So I encourage people to try and achieve good lighting conditions with
> oldfashioned pointlights / spotlights, because it teaches us some
important
> lessons. If a scene looks great without radiosity, it means we have done a
> good job setting up light, and radiosity will add the final touch. On the
> other hand, if we have done a poor job setting up light, radiosity will
not
> help much.

Yes that's true - it's certainly always nice to reduce render time by
avoiding radiosity if possible, by use of clever lighting.  I've been
experimenting with radiosity recently, using Tim's two-pass method as a
starting point, and the render times are already becoming tedious (although
before I was using the two-pass method it was taking exponentially longer to
get good results!).  The only reason I suggested keeping radiosity was
because it was looking, in my opinion, exceptionally realistic already.

> It has come to my knowledge that lots of professional work today does not
> use radiosity, or any other kind of advanced algoritm for solving
> global-illumination... In movies, G.I. are often faked with fill-lights or
> painted into the bitmap textures (eventually baked into them). For
example,
> there is a new movie out called "Troi". I haven't seen it, but I have read
> about the CG sequences of the city Troi and some battles on the fields. It
> looks pretty realistic but does not use G.I.! The artists explain that
G.I.
> would have been impractical. For one thing, it would have been much
slower,
> but even the large studios and render-farms run into problems with memory
> capacity, and even the most expensive render-engines cannot always handle
> an animation without G.I. artifacts. (They should've used POV-Ray instead,
> hehe... well)

Heh.  Yes a lot of movies can skip the use of radiosity simply because they
use scanline renderers, which allow you to implement a lot of tricky
lighting and shader techniques without a large hit in rendering performance,
thus it doesn't really make sense to use radiosity unless you really have
to.  There's a great new renderer called Maxwell that does an exceptionally
good job of global illumination - the advantage of Maxwell is that you can
set the amount of time you want the render to take, and it'll do the best it
can in that time (the longer you leave it go, the less grainy the end result
is - grain and artefacts are always the problem with using global
illumination in animations, as you mention).

However, in renderers like POV-Ray it's much more difficult to simulate the
effects of radiosity by just using area lights because it quickly becomes
slow again anyway (unless you want a lot of artefacts), so my personal
preference is usually to wear the extra rendering time and use radiosity :)

> I don't discourage the use of G.I. either! Especially in complex indoor
> enviroments with walls, and detailed objects with many holes and creases
> where the light creeps in, radiosity is certainly the best solution. And
in
> still-images it's often not much of a speed issue, provided it's used in
> conjunction with pointlights. But radiosity is only an aid; it does not
> replace the need for good, manual lighting.

I agree :)

Lance.

thezone - thezone.firewave.com.au
thehandle - www.thehandle.com

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> Or if you want perfection that will guarantee smooth, thin lines: +AM2 +A0.0
> +R2 -J

Hey Hugo,

that image I posted was rendered with +AM2 +A0.0 +R1 -J
I can only eliminate the AA problem with a +R3 (I've tried 2 and the
aliasing is still visible) does the "scale" of the model affect the
anti-aliasing or rendering in any way? I think I'm using a quite big scale
here.. the cabinet is around 13x8x7 pov units. does that affect anything?


thanks again,
Alex Verstraeten.

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Hi Alex,

The scale of your scene does not affect anti-aliasing, and the scale you're
using is perfectly normal.

I use +R3 for most of my final renders. It's a pretty good setting, but +R2
is also enough in some cases.

Sometimes +A0.0 is not needed, and will just slow down the rendering for no
good reason. But in this case, it's probably the only way to avoid "broken"
lines.

What was the render-time for the above image? (and your CPU speed?)

Regards,
Hugo

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