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Poser - OFFICIAL F.A.Q (Last Updated: 2025 Feb 24 11:54 pm)



Subject: How to light the fire? (Poser 5/6)


diolma ( ) posted Mon, 04 September 2006 at 4:04 PM · edited Wed, 26 February 2025 at 4:52 PM

OK, I have my scene set up, dog lying on rug in front of fireplace, fire in grate, rest of family sitting on sofa, watching TV...

A few dim lights around (blue-grey spotlight from the TV, a couple of fairly dim yellowish lights just to provide some slight modeling in other areas)...

But the focus of the pic is supposed to be the light from the coal/coke fire falling on the dog.

And there, I've utterly failed.
I've created a "bed of coals" as a prop (part of a stretched sphere with some displacement attached) and placed it in the grate.
I can texture it to get that "glowing coals" effect (using the same displacemnt map, in negative, to drive a colour ramp attached to ambient).
What I can't work out is how to get the fire to actually cast light, such that I get a realistic "distributed light source" coming from the fire...

I've tried using the disp. map as a transparency map and putting a point/spotlight behind the coals, but the light doesn't seem to penetrate properly (and the transparency affects the appearance of the "bed of coals" to bad effect).
I've also tried several other approaches, but gave up. So I thought I'd ask here:-)) Someone, somewhere must know:-)

Cheers,
Diolma

(PS. I can't post images of the scene I'm trying to create. It's for a possible client, if I can get it right..)



Connatic ( ) posted Mon, 04 September 2006 at 4:21 PM

The Gather Node is one way to do it.  It is a very slow render when used, and may require some experimenting.  Search the forums, as there is a detailed thread about using it.


diolma ( ) posted Mon, 04 September 2006 at 4:30 PM · edited Mon, 04 September 2006 at 4:31 PM

Thx, Connatic, but the Gather Node wouldn't do what I want. I'm not looking for "reflected ambience" (which IIRC is what the gather node does), I'm looking for a way of creating diffused lighting from the fire...

But thanks for responding anyway:-))

Cheers,
Diolma



lesbentley ( ) posted Mon, 04 September 2006 at 5:21 PM · edited Mon, 04 September 2006 at 5:28 PM

file_353212.jpg

> Quote - I've tried using the disp. map as a transparency map and putting a point/spotlight behind the coals, but the light doesn't seem to penetrate properly (and the transparency affects the appearance of the "bed of coals" to bad effect).

Select the "coals", and from it's Properties turn off 'Casts Shadow' the light should now shine through it, without turning the prop transparent to look at. As to the spot light itself, you may need to increase the 'Angle End' or even use several lights pointing in diffrent directions to get the light to spread over a wide enough area. You may also want to play with the 'Dist End' dial to make objects further from the fire look darker. If your having trouble getting a wide enough spread of light another thing you may like to try for the light is my "P5-Omni-12" available in the free stuff, but it's never been tested in P6, so you (don't pay your money) "and takes your chances".


scott8539 ( ) posted Mon, 04 September 2006 at 5:31 PM

i think i know what your talking about.try using the light for the fire and check atmoshpere box adjust setting low.thats how i get a volumetric look.if thats what you mean.


Connatic ( ) posted Mon, 04 September 2006 at 7:33 PM

I really do believe the Gather Node can approximate an object acting as a lightsource.  I've done it successfully.


Fazzel ( ) posted Mon, 04 September 2006 at 10:10 PM

Quote - > Quote - I've tried using the disp. map as a transparency map and putting a point/spotlight behind the coals, but the light doesn't seem to penetrate properly (and the transparency affects the appearance of the "bed of coals" to bad effect).

Select the "coals", and from it's Properties turn off 'Casts Shadow' the light should now shine through it, without turning the prop transparent to look at. As to the spot light itself, you may need to increase the 'Angle End' or even use several lights pointing in diffrent directions to get the light to spread over a wide enough area. You may also want to play with the 'Dist End' dial to make objects further from the fire look darker. If your having trouble getting a wide enough spread of light another thing you may like to try for the light is my "P5-Omni-12" available in the free stuff, but it's never been tested in P6, so you (don't pay your money) "and takes your chances".

I would think a point light would simulate a fire better than a spot light.  After all the light
from a real fire is omnidirectional.  It would seem also that if you used a point light you
wouldn't need several of them pointing in different directions like you would if you were
using spot lights.



thefixer ( ) posted Tue, 05 September 2006 at 2:13 AM

Agree with Fazzel, I have used a point light many times for this effect, you have to adjust your angles and distances right though!

Injustice will be avenged.
Cofiwch Dryweryn.


Dave-So ( ) posted Tue, 05 September 2006 at 6:19 AM

I haven't looked at this in Poser 6, but is their a way to give the light falloff...or apply a gradient so the light is brighter at the source and diminishes outward?

Humankind has not woven the web of life. We are but one thread within it.
Whatever we do to the web, we do to ourselves. All things are bound together.
All things connect......Chief Seattle, 1854



JOELGLAINE ( ) posted Tue, 05 September 2006 at 6:52 AM

Two point lights will do it.  One with a fire color (dark orange ambient) and another with yellow-orange caustics on it.  Stick them on top of each other in the center of the flames object.  Violia, fire-light.

It's not perfect, but it IS quicker than some other offers in the render department.

I cannot save the world. Only my little piece of it. If we all act together, we can save the world.--Nelson Mandela
An  inconsistent hobgoblin is the fool of little minds
Taking "Just do it" to a whole new level!   


Tyger_purr ( ) posted Tue, 05 September 2006 at 8:34 AM

file_353289.jpg

I did this some time ago in P6. i used three point lights, yellow red and orange in the fire (and on on each candle) and an ibl with [ these](http://www.runtimedna.com/mod/forum/messages.php?ShowMessage=184683) masks to control color and brightness.

sounds like your going for something similar

My Homepage - Free stuff and Galleries


Tyger_purr ( ) posted Tue, 05 September 2006 at 8:49 AM

Quote - I haven't looked at this in Poser 6, but is their a way to give the light falloff...or apply a gradient so the light is brighter at the source and diminishes outward?

yes. point lights and spot lights have a begin and end distance setting (i dont recall exactly what they are called at the moment) that control falloff.

My Homepage - Free stuff and Galleries


diolma ( ) posted Tue, 05 September 2006 at 2:57 PM

Many thanks for all the replies!

I'll try all of them in the next few days, but lesbently's tip to turn off "cast shadows" suddenly gave me a "penny just dropped" moment..:-))

Cherrs,
And thanks a gin,
Diolma



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