Lighting And Rendering Monika

Lighting fit for a super model

The lighting direction for this project was pretty straightforward. Basically, we are creating a super model type of image, which means make her look hot! The best way to tackle any lighting project is to translate the stage direction, like "make her look like a super model" into something useful to you as a lighter. What makes a woman beautiful? Deep, liquid eyes, full lips, smooth clean skin, and a good form on the face. Luckily, the textures and model on this particular project are top notch, so the form and smooth skin are pretty much in place. Also, you need to understand the opposite of your objective. Male models are all about structure. Lighting should emphasize high cheekbones, strong jaw line, strong eyes, etc. So those are things we probably want to avoid with this lighting set-up.

To get underway, I first took a look at the model to see if there was anything we needed to be careful about when lighting and rendering. At this point, you need to make sure the geometry is in good shape and the UVs make sense. If you are planing to use something like displacement, it is paramount that the surface and UVs are super clean, or you are in for a lot of fix-it headaches. Like I said, the model is of very high quality, so we are covered there. The next thing is to look at the textures. These are also super nice. However, all the textures were provided at 4K. Excellent for image quality—possible headache in the pipeline. The demands for realism and image fidelity are always on the rise, so you have to find an economical way of dealing with the large file sizes.

This is where map textures with mental ray come in. They will save you—end of story. I have had multi-gigabyte textures burning over a hundred processor render farm with absolutely no problem or network bottle-necking due to MAP They are magic, use them!

So now I am ready to start rendering. I came into this project late, and the timeline was crunched, so speed was a critical concern. I needed to get a photographic render, and couldn't afford to spend hours setting up lights. I needed a shortcut. Enter Image Based Lighting (IBL). IBL might be the greatest thing to ever happen to CG lighting! It doesn't do color bleed, or photon mapping. It does do amazing diffuse lighting and soft shadows. In short, it will get you to real faster than any other method. The downside: if you don't know what you're doing, it can be prohibitively expensive to render. As the name implies, IBL is all about the image you use, so you must choose wisely, selecting one that represents the illumination setup you are looking for. There's no better image type for IBL than HDRI. Now that we have our illumination model, it's time to look at the eyes. Eye's are about three things: reflection; refraction; and specular highlights. Reflection is obvious—you need the eyes to look shiny and bright against the soft skin of the face. They need to look liquid, which has a lot to do with using the cornea to refract the iris and attenuate the light traveling through it. Finally, you need a "figure" light to pop a hot spot in the eye. I used an area light that was just linked to the cornea geometry to achieve this

124 ESSENCE The Face

Lights, camera, render

Lighting and rendering Monika

O Step 1: HDRI

A High Dynamic Range Image is a file that holds multiple exposure of the same image By bracketing up and down when taking the images, a photographer is able to ensure he has information in the brightest and darkest parts of the image These images are then combined into a single file, which can be used as light and reflection sources within 3D packages. HDRIs are especially good as a reflection sources because they provides for the full range of highlights and shadows on your ray traced objects.

Q Step 2: IBL nodes m ^ that \a/p have our illumination model, it s time to look at the eyes. Eye s are about reflection refraction, and specular highlights. Reflection s obv^s-yo need the eyes to look shiny and bright against the soft skin of the face They neea t0 l00k liquid, which has a lot to do with using the cornea to retract he iris and attenuate the light traveling through it. Finally, you need a figure light to pop a hot spot in the eye. I used an area light that was just linked to the cornea geometry to achieve this.

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