In Realitools Volume 1, programmer Brenden Mecleary introduced a LightWave Fresnel shader....
Then, in LightWave 5.6, NewTek released Real Fresnel...
Now, it's Realitools Volume II.
Welcome to the mother of all Fresnel plug-ins.
It simulates the fact that some surfaces change depending on the angle that you view them at.
That's cool, you say.
And Realitools2's Fresnel2 plug-in IS the most powerful one on the market.
Great, you say. Glad I own it.
Then you open up the interface and....
(Okay...keep breathing...stay with me here...deep breaths...everything will be okay....)
Still with me? Good.
It IS kinda scary. Overwhelming, in fact. But relax...it's not that hard to understand.
Sure, it seems like a lot of buttons. It IS a lot of buttons. But if you look closely, you'll notice that it's really a lot of the same buttons, over and over again. If we were to just focus on one little section of buttons, like this...
...it's not scary at all. It's just when you see ten of those puppies all stacked up that you feel the room start to spin.
What's really going on here? Let's start by reminding ourselves what the Fresnel effect does - it changes the appearance of the surface depending upon from which angle we look at it. Keep that in mind - we're basically dealing with two variables; namely, surface values and angle.
If we went into the interface, the Color tab is chosen by default. If we were to go to the top line of the main section of the interface, and change the R value to 255, the interface will look like this....
Compare this interface with the one above, and you'll see that we only changed one thing. Forget that you don't know what any of this means yet - let's look at the first line of the interface section that we changed.
So, what does this mean? Let's look left to right.
The ON button determines whether this value is being used in the Fresnel effect. The Position section determines what angle the value is set for - in this case, color. So, our position of 0 (zero) means that when viewed at 0 degrees (straight on), the surface will have the Value selected on the line - in this case, RED : R-255, G-0, B-0.
Now, let's look down at at the bottom of the panel, where the line says.
First, the ON buton is on. The position of 90 means that when viewed at a 90 degree angle, the surface will appear to be black : R-0, G-0, B-0.
Simple enough, right? Let's review - this line means that polygons with this surface will appear Red when viewed at 0 degrees, and will appear Black when viewed at 90 degrees. Between 0 and 90 degrees, there will be a smooth transition from red to black.
We can see this if we look at the Preview section of the Fresnel2 interface. It looks like this....
The top part of the preview shows the range of positions, going from 0 to 90 degrees. You can see the nice smooth transition from left to right. The bottom part shows the Dissolve, which we'll discuss later - suffice it to say that right now it's all black, which indicates 0% dissolve.
One problem - we haven't actually affected anything yet. If we look to the left of the Preview section....
See that little Enabled button? See how it's not on?
There are Enabled buttons for every single tab in Fresnel2, in addition to the Enabled button for the whole plug-in at the top of the interface. If you don't have the Enabled button on for the tab - in this case, the Color tab - you won't get any effect.
Simple enough, but trust me - you will forget to turn this button on from time to time. You will change a whole bunch of settings, do a test render and...nothing, nada, zilch. You probably forgot to turn on the enabled button. Remember that. Let's turn it on.
Now, when we click the little Sample ball, it changes...
What does the sample ball mean? Think about a sphere - the polygons right in the middle are pointing right at you; as we move towards the edges, the polygons face further away from us. For that reason, a sphere is a pretty good way to visulize what the Fresnel2 plug-in does. As you can see, the center (0 degrees) polygons are red on the samples sphere, and as we move towards the edges (which eventually face 90 degrees) we smoothly fade to black.
If this isn't perfectly clear to you yet, hang in there - we have a very visual example coming up. Let's change the color of the 90 degree position from black to blue (R-0,G-0,B-255) - click on the sample ball and our interface will look like this...
With that done, let's move on to the next section....
