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View Full Version : A couple of questions about lights...



focus3d
12-13-2004, 09:21 AM
OKay I am trying to do the volumetric fire tutorial, as I am creating a christmas scene with a nice roaring fire. My problem is that I have tried using the distant light as my source as the tutorial suggests, but everything in my scene appears to be lit from beneath, even if I put the light above the objects!! (or move it about for that matter).

The 2nd problem is that I tried a spotlight instead, the fire looks great but the light still has a cone that is illuminating my fireplace, even if I turn down the light intensity to 0. ??

Attached are some very crude renders to show you what I mean, how do I turn the light off completel? (I have texture only enabled by the way).

Any help greatly appreciated...

bloontz
12-13-2004, 10:12 AM
Are you setting a keyframe after positioning your lights? If you don't (and don't have auto key on) your lights will snap back to their original position when you render.

Weetos
12-13-2004, 11:55 AM
Concerning your first problem, it looks like you moved the light above your scene, but you didn't mention you rotated it so it was pointing down. I doesn't matter where a distant light is located, what matters is where it points at. Rotate it (using y key) so it 'looks' down (set your viewport to 'light view' if you want to make sure your light is pointing at the right direction )

Ztreem
12-13-2004, 03:59 PM
I would use a point light with a warm yellow color to make the fire light up the scene.

bloontz
12-13-2004, 05:06 PM
In the Lights panel of the Objects Properties dialog there is the ability to exlude lights for the selected object, that should be one way to eliminate the light cone in the second pic.

byte_fx
12-13-2004, 05:31 PM
First off - an often overlooked feature of LW lighting.

It is possible to pick and choose which objects any light affects.

This can be done from either an object's property panel or a tab on a light's properties panel. Which one is the fastest to use depends on the number of lights and objects in a scene but either gives the same result.

For your scenes I would suggest maybe four or five point ligjts with different intensities and falloffs to simulate relative hot spots within the burning wood.

You may need to disable some objects being affected by them but probably not.

Using the spinning light trick on each light will softone the shadow casting for a more realistec appearance.

Volumetric lighting - if you position a null and use it as the parent for the volumetric textures then all the lights will be in sync regarding the volumetric effect. You may or not have to turn on world co-ordinates for the texture. This varies from scene to scene.

Although your're doing - I presume - a still render this setup works really nice for animating a fireplace fire. Just add some overlapping envelopes where needed and give the volumtric texture some movement.

Hope this helps.

byte_fx -

p.s. once again I've typed too slowly.

focus3d
12-14-2004, 01:39 AM
Thankyou so much for your help everyone, that was greatly appreciated, and very useful!

Cheers

Focus3d