Lighting to simulate fire?

Deke

Is there a great trick to lighting a scene as though it were lit with firelight? I plan on comping in some flames in After Effects but would like some interaction lighting on the characters. I think in AE this would involve a wiggler style formula that varied the light intensity. I could do that by hand to a light in Daz, but wondered if there was a better way. Using Daz 4.7 on a mac.

Richard Haseltine

uberPoint comes with a gel for flames, or you could simply apply uberArea Shader to a flame prop and use it's diffuse colour for the Colour and its transmap for Intensity.

frank0314

You can adjust the ambient on the flame to get it to glow if you need that as well

kaotkbliss

On one scene I did that had a fireplace, I used point lights with an orange color selected for the light. I also set the strength of the light way down (to something like 45% or so with a relatively short falloff, just enough to hit what I wanted the light to hit)

Whitehart Creative Arts 3-D (fionathegood)

I am new and needed to do something similar recently. I found a great deviant-art tutorial but I lost the link, so bear with my wordy and pictureless explanation. If I find it I will post it again but for now... mostly how to do what the admins said a post or so above me, with a couple additions, ie the explanation "for idiots". ;-)

I would find a square-ish format 2D image of the flames that I wanted with a black background. (Make sure the blacks are absolute black and the lightest lights nearly pure white). Next create an "Uber Area Light Base" primitive in the scene. Delete the Uber Environment Light that comes with the Uber LightPlane. (Critical step!) Then select the Uber Area Light and under the "surfaces" tab use the image of the flames in the diffuse and ambient slots. Set diffuse to 100% and ambient higher than 100% to emit light. In the diffuse map, darks show up as a dark parts of the image and lights as lighter parts (like a typical image). In the ambient map, darks will give off less light and brighter colors more... This will look like a glowing rectangular picture of a flame unless you adjust the Opacity!

To create transparent flames that emit light: First, put your color image of the flames in the Opacity slot. In photoshop or a similar program, convert your color flame image to a black and white version. Basically when rendering with settings provided by a shader program the opacity strength tells the renderer how transparent or opaque to make the surface. Anything completely black will render as invisible, your darks will be very transparent, and your lights nearly opaque. Pure white will be completely opaque. This is why you don't need to create or hunt down flame shaped 3-d geometry and can just cheat and use a rectangle with a few maps. So, when making the map, leave anything you want to "disappear" black, and then make the rest of the image that you want to look like transparent flames into a greyscale version of the image. You can play with how bright, dark and contrasty the opacity map is to create the best effect. The only critical piece of creating the map is that the parts you want to disappear are black. I don't think flames are every 100% opaque, so pure white is also like not very accurate. I think the "mid-tone contrast" option in photoshop would be useful! Lights will be more opaque and darks more transparent... be aware that while transparent is very "flamelike" which is nice, your cheater rectangle also needs to be available to emit light, so don't make your maps too dark! Use this black and white map in the "opacity strength" map slot. If you want to have the darker areas of the 2D image to also emit less light in the 3D scene, use the same or similar black and white map for the ambient strength map as well (ie this would make blues give off less light than the yellows like a typical flame, although they will already give off less light because opacity makes them more trasparent.)

Pop the ambient strength up high so the plane emits as much light as you want. Be aware that too high on the ambient will cause "glowing edges" where colors meet on the map. You can leave the "colors" option slot in the diffuse, ambient and opacity slots set to white as the map tells it what color to render. (You can change the color, however, to blend with the map and create a color shift or washing out of colors in the color map). Its pretty simple to change the size and shape of the flames without by simpy manipulating the x and z scale of the Uber Light plane primitive. You can use multiple primitives and rotate them to create a sense of depth.. Also, unlike regular 3-d plane geometry which is one sided (transparent from the back), the Uber LightPlane will emit light from both sides. :-)

Hope this helps, and if I said anything incorrectly or there is a better way or more correct explanation, I hope more experienced than I will chime in!