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Subject: 
Re: Anyone willing to render a scene for me?
Newsgroups: 
lugnet.cad.ray
Date: 
Mon, 10 Feb 2003 13:45:15 GMT
Viewed: 
783 times
  
I am not a POV guru or a programmer, so when I want to render two pictures
of an indoor scene, but I have almost no clue how to do it.


Well, it seems like you're off to a good start.

The scene is of 16 minifigs in a living room, sitting more or less in a
circle. Ideally, the only light would be noonday sunlight coming in through
a picture window.


First thing you have to know is that you can set up a scene which would work
fine in real life and not render properly in POV or any other program. This
is because real lightning and digital lightning differ in certain key aspects.

I did create a "sun" light outside the room, but the interior was entirely
in shadow.

That is because your "sun" is not shadowless (look up in POV's help the term
"shadowless" to understand its use). If it casts shadows and your room is in
the shadow, it will render dark (or even black).

The first question you need to ask yourself is "If I am rendering an
interior at midday, does the exterior light have an impact on the scene, and
if so, which". Unless the sun's light is drenching from the bay window, you
might now even need a sun light at all! The light we get in unlit interiors
during the day is mostly reflected, rather than direct light.

In an attempt to lighten it, I began playing around with some
basic radiosity, but still have little idea what I'm doing!


Radiosity one of the ways to reproduce the effect of reflected light on 3D
CGI. However, it seems like people jump on it thinking it will be an easy
solution to all problems when it is hardly so. In fact, I recommend that you
try to model the effect of reflected light using traditional lights first.
For one thing, you will learn a lot more a lot faster than if you spend the
time trying to figure out what the different radiosity controls do without
much prior knowledge of basic lightning. Of course, this is not to say that
radiosity doesn't have its place. But one thing to consider is that 99.9% of
commercial 3D computer-generated *animations* (not stills) are not even
ray-traced, using quicker and less precise shadow map algorythms. If
radiosity is not even an option from the pros, there must be other ways to
accomplish it.

So, is there anyone who would be willing to make this scene for me? There
are more details to discuss, but I wanted to find out if anyone is
interested.

I can't pick this up right now, but here are some tips.

1. AMB = 0. The ambient (or ambient light) parameter is a nasty way to fake
general reflected light in the shadows. Unfortunately, instead of bringing
out details in the shadows, it actualy kills them with inadequate muddled
tones. With AMB = 0, anything that is not directly lit will become pitch
black. But pitch black is actually good for the creator of the scene, as it
gives him or her complete control over the lightning - a black shadow to a
3D CGI artist is like a white canvas to a painter.  You might also want to
crank up DIF (diffuse) values to between 0.6 and 0.8. Look up diffuse in POV
help file to see what it does.

2. Place one dim shadowless light in the center of each wall of the room -
this way you will be faking the light from the sun coming from the window
and reflected on the walls that reverts back into the room, which is a good
way to fake interior reflected light. Shadowless lights can be placed
anywhere, even outside the walls, since their light is not interrupted by
objects.

3. Ideally work with one light at the time. First turn all of them off and
render the scene. Is it pitch dark? Good! Now  render the scene with only
one light turned on - do the same for all lights and you will soon realize
what each one is adding to the scene - you might need to move a few or even
add new ones. Obviously the combination of all of them is what will drive
the success of your rendering - if you have more than one light on the scene
turned on and you are not sure of the particular effect each one is having,
turn them different colors and you will see which is illuminating what and
where do they meet.

There are a lot more tricks to it, but with these basic tips, you should be
able to at least render an interior with a light that somewhat resembles
what you are looking for. More importantly, as long as you can figure out
where the lights are located in the scene (you might want to define the
lights directly in the DAT file using the LIGHT.DAT part), most of your
actions and their effects will be easy to follow and will make sense (some
sense, anyway). You will find yourself climbing up the learning curve
without even realizing it. Be aware that with programs like POV, it is
extremely easy to learn a few routine tricks and then never actually move
beyond that, hoping for the program to crack open of us and ultimately never
really progressing in its usage.


Thanks!
--Ryan
ryanjf@ifriendly.com
http://users.ifriendly.com/fourfarrs1



Message has 2 Replies:
  Re: Anyone willing to render a scene for me?
 
"miguel agullo" <technicpuppy@yahoo.com> skrev i meddelandet news:HA3I7F.GAD@lugnet.com... (...) I've also found that a *dim*, shadowless light at exactly the same position as the camera more or less guarantees that everything you *see* is also (...) (22 years ago, 10-Feb-03, to lugnet.cad.ray)
  Re: Anyone willing to render a scene for me?
 
miguel agullo wrote: [snip] Thanks for the suggestions, Miguel! They are very insightful and encouraging! --Ryan (22 years ago, 10-Feb-03, to lugnet.cad.ray)

Message is in Reply To:
  Anyone willing to render a scene for me?
 
I am not a POV guru or a programmer, so when I want to render two pictures of an indoor scene, but I have almost no clue how to do it. The scene is of 16 minifigs in a living room, sitting more or less in a circle. Ideally, the only light would be (...) (22 years ago, 9-Feb-03, to lugnet.cad.ray)

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