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daz1761
05-20-2012, 02:22 PM
Im currently building a little scene that currently has my favorite gradient blue background as it does the job normally. But this time I have been given an idea to have the scene lit up as normal then to all of a sudden go 90% or so dark so I can reveal objects that glow. I know this can be done with envelopes but im not too sure how to tackle the job. This is how my scene looks at the moment, although the scene is intended to be set in a bedroom.

BeeVee
05-20-2012, 02:55 PM
Envelopes is exactly right. If you just set a light value it's for the whole scene, but clicking on the E opens a Graph Editor. On the Graph you have intensity going up the left-hand side and time horizontally. You can start your scene at 100% and drop the value down to 10% at a certain point. You will need an additional key in there to tell LightWave where you want it to start lowering the light, or you can just set the incoming curve to Stepped.

B

daz1761
05-20-2012, 03:41 PM
Nice one, so you recommend I turn my background to black and build a box around my scene, or can i get away with keeping it as it is as I am on a tight schedule ? So how do you control all lights at once? I thought you needed radiosity for that, mind you I've never done it before :)

Thanks

BeeVee
05-21-2012, 02:59 AM
Envelopes are made on a per-light basis. How many lights are in your scene? If you want to just have one light that controls the rest you can always use a Channel Follower modifier on the other lights. I've made a quick example for you. You will need to just add a Ground Plane object in Layout because without some geometry the lights are not visible in and of themselves. You should be able to turn on VPR and see how the first light circle fades to the right over the course of the animation. The way it works is that the first light (MasterLight) is the only one with an envelope, with the light dimming in two steps. The other six lights in the scene all use a Modifier called Channel Follower that uses MasterLight's intensity and there is a lag added to each light going right. If you change MasterLight's Intensity envelope the others will all follow suit.

Hope this helps, :)

B

Danner
05-21-2012, 04:36 AM
I would make two scenes using two sets of objects but the same camera move, that way you have total control of the look of each one, and just fade between the renders in post.

daz1761
05-21-2012, 05:48 AM
Thanks BeeVee :) That's just the ticket! I like the lag effect too. That definitely looks the easiest solution for dimming all lights. There is only 1 distant light in the scene at the moment, but I guess a few spot lights will be placed in there in the end. I'm still a bit confused about the scene in general, do you think I should have what I've got now but in a big box so that the background image doesn't interfere when I enable my glowing objects?

Surrealist.
05-21-2012, 06:32 AM
Making a box will change your lighting scheme entirely. The sooner you introduce the box the better. That way you can start lighting for it right away. I would not attempt to describe all about lighting here. But a very quick tip is to determine where the light is coming from in the scene. A window? A lamp? Then light accordingly.

A good idea would be to search for some lighting tutorials for LightWave for some good workflow tips, and keep it as simple as possible with the number of lights you are using.

Some more quick tips:

A 2 light set up with a window:

A single point light in the center of the room for ambiance. Adjust the fall off so that the light does not fully light the corners of the room.

Turn the Light Property ambiance to 0

Use a Spotlight or Area Light pointed into the window with shadows on.

don't use the distance light or alternatively you can use the distant light with shadows on rather than a spot or area light. But rotate it so that the direction causes a light to come in the window.

Use Ambient Occlusion on the surfaces of objects to add more realism.

Single Light lamp set up. No windows:

Simply place the light where the lamp would be or is. You can imply it off screen if you are not going to model one. The set up can be more complex if you actually have a lamp and you may want to use two lights in the same location this case. One to light the lamp excluding the room and one to light the room excluding the lamp.

Ambient occlusion on surfaces.

Global Illumination opens up another can of worms. And may not be in your time frame. But there are options there as well. The Ambient occlusion on object surfaces is to fake Global Illumination. You don't have to use it, but it adds more realism.

Another idea is not to use an entirely enclosed box. But only two walls and maybe a floor. Then light the entire scene with one Dome light and maybe one additional light for highlights. This will give you a good fake for Global Illumination and you can use Ambient Occlusion along with this for additional effect. Or just use the dome light alone.

K-Dawg
05-22-2012, 04:41 AM
Thanks BeeVee :) That's just the ticket! I like the lag effect too. That definitely looks the easiest solution for dimming all lights. There is only 1 distant light in the scene at the moment, but I guess a few spot lights will be placed in there in the end. I'm still a bit confused about the scene in general, do you think I should have what I've got now but in a big box so that the background image doesn't interfere when I enable my glowing objects?

If you want the lighting from your background but not the background itself you can either use the compositing tab CTRL+F7 and set the background to black, or render as is and render the alpha maps with it and use that in Comp to add a different background.