Technical Slop

Donut II: Finishing Curves

Man, this next part is kind of heady. The first part of building the donut D-Map was particular to building that particular D-Map. Now, whenever you use the "creative visualization of slopes" idea, the following applies. Even if you use Emboss or Lighting Effects to make your D-Map, this stuff still goes. Well, it goes if you actually want to bother with it.

Remember this? The highlighted area is where we two different spots to grab from.

Remember this, too? Those are the two spots that we want to grab the highlighted area. The problem is that they grab the same distance, but not the same spot.

Keep your eyes on those two spots.

Let's peak at the Red channel of our really cool donut D-Map. Look at the black where those two spots should be. Lots of black, and the one spot is causing a problem. It needs to be toned down.

Sounds like a job for Curves!

Start a new Curves Ad-Layer, go to the Red channel, and bring the point in the lower-left up to 128.

Notice that:
Input: 0
Output: 128

That's good and all, but it's going to bring all of the black in the Red channel up to 128. Can't have that. What we want to do is bring the black on the left, or west, up to 128, and leave the rest alone.

Sounds like a job for a gradient in the Curves Ad-Layer Mask!

Just lay down a White to Black gradient like so. Now, all the black on the left, or in the west, will be brought up to 128. As you move to the right, or travel east, the black will be affected less and less.

Sounds logical, right?

Here is the new and improved Red channel. The black on the left western shore is now more neutral. The other black area has been lessened a tad, but that's fine.

Okay, so let's apply the same idea all the way around. Eventually it will looks something like this:

How's that for a monster graphic? That's actually the goblet that I showed earlier, but the Curve Ad-Layers will be the same for the donut.

On the donut, this is what the final D-Map looks like.

:whew:

Man, that's a lot of work. Maybe some day I'll try to record an Action to do the Curve Ad-Layers for me.

Looks good to me. The inside looks good, and there is no wrap around taking effect on the outside.

Why, it's almost magical. But it's not really magic because we know how it's done.

Math? You hate math, don't you?

For these, a little bit of math is good. Let's say our document is 256x256. We want pure white to grab a maximum distance of 256px. The only places we'll have pure white, or pure black, is at the extreme edges. Since 100% = 128px, we use 200% for 256px. Since this incarnation of Biker Chic is 200x200, we use 100% / 128px = m% / 200px. That means that m% = 156%.

Am I banging my head against a brick wall with the math? Probably. But don't worry too much about it if you don't want to and just wing the percentages. Half of the fun sometimes is being pleasantly surprised with guesses.

That's what Biker Chic looks like with 156% both horizontal and vertical. Believe it or not, but that is awfully close to what a 3d prog will spit out. (When I get the chance, I'll toss up a render so you can compare.)

For some reason, I always get some really nasty jaggies when doing this kind of thing. I haven't really been able to figure out why. I suspect it's a combination of several things. With a touch of Gauss and some finishing touches, the jaggies shouldn't be too noticeable.

Sure is a lot of work. But it's fun. Just one more thing to talk about. Hehe.

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