Join Craig Whitaker for an in-depth discussion in this video Setting up a Fresnel shader, part of Cinema 4D Rendering Tips for NUKE.
- Now that we've looked at some real world examples of where a Fresnel shader could potentially be a useful tool, let's jump back into Cinema 4D, create a Fresnel shader on our figure here before bringing it into Nuke to start working on some compositing tricks. So we have a figure here. Just 180 centimeter average six foot figure and that may seem like it's not important, but I just want to always stress the idea of modeling to scale. Okay, so, now let's double-click down in the materials and we'll just drag this to our figure.
We're going to double-click back to the basic tab, uncheck color and uncheck reflectance. I'm going to activate the Luminesce channel and then down in Texture, we're going to select the Fresnel shader. Now a lot of times when you're working in Cinema 4D, there's a tendency to put the Fresnel shader on the Reflection channel, which is great, but most people do stop there without looking at some other uses. What we could potentially use it for later in pipeline, so if I select the Fresnel shader, and you'll see that we have a white to black gradient, so if I render that to my picture viewer, I have now two controls.
Now this may look like some of the images that we saw in the previous movie with some intensity on the outside, and we lose it as we get in towards the center of the object or the core of the object. Now again, this is all based on the camera angle and that's kind of why I parked the camera at kind of an off angle here. So you can see sections like this, which you're getting the full white versus some of the sections like this that are looking directly at the camera and getting the black. Now, the issue here is that we're using two colors to control, right.
So now what I would like to do is to make it three by using an RGB matte instead of a black and white. This, we have three levels of control as opposed to two. Okay, so let's take a look at that. Let's double-click on the white and let's change this to pure red. Go all the way to the end, change this, to pure blue. Okay, now what we're going to do is we're just going to click right in the middle, oh, did it happen to go right to 50? Hey, I probably couldn't do that again if I tried. Alright, so let's click here.
And we'll change this all the way up to pure green. Take out all this stuff. So now we have an RGB control instead of a black and white control. So now we have three levels of color. Now this may not seem like a big deal now, but by having three colors as opposed to two, once we get into Nuke, we can start using some color grades, some gamma controls, and really shift around all these red, green, and blue colors and now there's three levels.
You can have something for the inner core. Let's say we're going to come up with a glow, which is what we're going to tackle in the next movie. If we were trying to give this thing a creepy ghost glowing type of look, we can now have a glow for the inside. We can have a glow for the middle section, and then a real strong hot edge glow and we could have three separate controls by doing that. What we'll do is we'll make sure that when we go into our render settings, we'll go to Save.
Change this to OpenEXR, which will render a 32 bit image, again one scan line at a time, and now by rendering a 32 bit image, we'll get every single color in the gradient all the way from the left side of the gradient to the right side, giving us most flexibilty once we get into compositing. So I'm going to render out this figure. We're going to jump over to Nuke and start setting up our glow controls.
- Prepping UVs for export
- Using the STMap node to retexture objects
- Compositing the shot
- Creating RGB mattes
- Working with Fresnel shaders
- Creating depth of field and motion blur effects