First, what's Radiosity ?
It's basically the best way to light things, for rendars, and for prelit models, just like GTA uses. Radiosity is a very powerful calculating process, that can simulate real life lighting. With particle effects, expositions, exposure controls, volumetric lights, fog light simulation and reflect-refract uv each others.
Vertex Colors, What you need to know (read carefuly) :
When rendering a vertex color system to a mesh, you need at least two parameters to be filled.
- First is the quality of the scene lights. Lights needs to be alway 3/4 view from the model for exteriors, and need to use soft shadows parameters (shadow map). The exterior light is never white. Always use a small ammount of yellow-grey to it.
For interior lights needs to be diffrent, you need to work with renders before starting to apply the vertex colors. You'll have to play with intensity, far attenuation, and advanced raytraced shadows. Note, when using more than 8 lights, max will not show the further added lights in the viewports. Only in the renders. For interiors, use a white-blue neon color, and an intensity of 1.0 for light sources that generate shadows.
Hint : If you placed all your lights correctly, but the scene is way too dark, please don't increase the intensity of them. Just add another small fill light with grey color, and 0.1-0.2 intensity.
- The other parameter needed for a good quality vertex color is the amount of polygons on the surfaces receiving projected shadows. Let me explain, since the colors are applied on vertex ticks, the more the vertex number is high, the more shadows and lighting changes will be noticeable. A good way to increase the resolution of a mesh without crushing it is Tesselate. Use it with tension to 0. It will divide your polies into 4, increasing this way the vertex used on your mesh. VERY Important.
The tutorial :
- Start 3Dsmax 8 or 9, whatever SP you have.
- Create your scene, if you already have one, merge it into the scene we're gonna set.
- Look at the picture :
- Go in the Render panel, Advanced Lighting window :
- Set all the parameters like on the pic !!! Very Important.
- You see the scene in viewport is still the same, normal. Place your lights, as explained before, at right place. Not on the neons, but a bit under. We're not in real life, omnis needs to be placed differently.
- Now that everything is tweaked as we want,
1. Press "Reset", to reset an old solution, in case you're rendering for a second time.
2. Press "Start", and then wait till the process is finished. It's gonna take alot of time on low end computers, and it'll also depend on the solution quality. For our example, 88% is a good ratio time/quality.
- Also the refine iterations are very important to get the best result. Wait till the refine iteration are done. Go get a cup of coffee, hot coffee.
=> When it's finished, follow this pic instructions :
1. Click "Setup" to set the Exposure Control Setting. For the moment, nothing is set yet.
2. Set the same automatic parameters as me.
Hint : You can tweak the ambient color, Color background and Tint of the lighting to get the right athmosphere settings you want. Each time you change one, press "Render Preview".
Hint : You can tweak Brightness and contrast aswell, but be careful with these value, because it's not really seen in the viewport, but after you applied vertex colors to the mesh. !!!
3. Press "Render Preview", Now you see the Radiosity Solution in the viewports. That's what we're gonna export with Kams Scripts, but before, follow these steps :
- Select the model that will receive the vertex paint, go in the tool panel, pop up the the "Assign Vertex Colors" panel (seen in basic tutorials).
- Set the SAME parameters as me, again. Make SURE you have checked "Radiosity, Reuse Illum From Solution" in the Options.
- Click "Assign to Selected" Wait till the computer has finished to take all the radiosity solution to vertex paint.
- You can now see exactly what's the result by toggleling the "VertexPaint" panel to the same state as in the pic below :
=> Last Step :
Use the same exporting values :
Here we are, now you handle the best lighting process. If you fail with this tutorial, you canstill use paint magic method, but that's far far from a radiosity quality.
Edited by ParoXum, 11 July 2008 - 11:51 AM.