Thus far in our series on Point Editing, we’ve worked with some very general information and done some basic adjusting. (To start with Lesson 1 in this series, go here.) Now it’s time to step it up a bit and dig deeper. In this lesson, which I’ve broken into 2 parts, we’re talking about how to change the type of segment you have and why you might want to. We’ll also talk about changing corner points into smooth ones and vice versa.

*Tutorial level: Intermediate to Advanced*

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## Line Segments

When you select a point, the line segment associated with that point turns brighter/bolder red. It’s only 1 line segment, even though the point connects 2 line segments. We’ll talk more about why that’s the case later. Just be careful to observe which one is that brighter red.

There are 2 types of line segments — flat ones and curved ones.

*About flat segments*

Flat segments are those that have no curve to them. Simple enough. You can tell that a segment is flat if, when it’s highlighted, you don’t see any blue boxes (Bezier Control Handles) going along the segment from the points on each end of it. (There is 1 tiny exception to this, but I’ll explain that fully farther down.)

*About curved segments*

A curved segment is one that isn’t flat. Pretty sure we all know what a curve is. When a line segment is curved, you’ll <almost always> see a blue control handle along the segment coming from selected point.

You might also see one going out the other direction from the point. That’s when the segment on the other side of the point is also a curve.

*Your eyes can deceive you*

Sometimes you have a segment that appears to be flat but is actually curved ever so slightly. This happens quite a bit on images you trace, particularly wording. You assume that it’s a flat line segment because it’s a flat area in your original raster image. But tracing isn’t precise so you can be fooled. (Cleaning up traced images is one great reason to learn point editing).

Another time that a curved segment may look flat is when the the blue control handle square is so close to the black point square that you can’t see it, or when the black dots are very close together.

Zooming in helps here.

*Changing segment types*

Nothing in the Point Editing panel or Quick Access Toolbar tells you if the highlighted segment is flat or curved. You just have to use your observational skills to figure it out in those 2 spots. In the right click menu, there’s a check mark next to the type. But let’s say you have a line segment in your design that’s flat and you want it to be curved or vice versa. That’s something you can do in any of those places.

Here my highlighted segment is flat. I know that because I don’t see any blue boxes.

I can click on Make Curve to change it into a curve. Then it looks like this. Notice the blue control handle now.

This highlighted line segment is a curve. I can tell because I do have blue boxes.

If I choose Make Flat, it looks like this. Notice that the blue handle on the side of the point along the highlighted segment is gone. The one on the opposite side is still there, because that segment is still a curve. My action affected only the highlighted segment.

Now here’s a curious thing. This segment is obviously a curve, but I don’t see a blue control handle coming off the selected point.

What’s going on? It’s an oddball circumstance that has to do with changing the types of points. I’ll show you in detail below, but first we need to learn more about smooth and corner points in general.

## Smooth and Corner Points

We talked about the types of points in Lesson 1, but let’s review just a bit. The type of point you have is always indicated in the Point Editing panel, the Quick Access Toolbar and the right click menu. It’s the one that’s highlighted or checked. That’s going to help us know what we’re dealing with before we try working with the points.

*About smooth points*

Smooth points are those that are on a continuous curve like these…

…or that connect 2 flat line segments that don’t change trajectory.

On a smooth point that joins 2 curved line segments, when you move one blue control handle the other moves in tandem with it. We’ll spend our whole lesson next time on understanding how to alter curves.

Remember that you don’t normally have a smooth point connecting 1 curved segment and 1 flat segment. I’ll talk about an exception to that below.

*About corner points*

A corner point is one that connects 2 line segments – curved or flat – that change in general direction.

Here’s a corner that has flat segments leading to it on both sides. You can see that the line segments aren’t following the same trajectory and there are no blue control handles. This gives us a sharp corner.

This corner has one flat segment and one curved segment. We know that because it has one blue control handle.

This corner connects 2 curved segments.

It looks very much like the smooth point along a curve that I showed you above, but it’s going to act differently when we try to adjust the curve. That’s why we want to know the difference between a smooth and a corner point. On a corner point, you can alter one curve and the other stays put. We’ll talk about how that works in our next lesson, but here I’ve adjusted the curve on one side of the point a bit. It’s easier to see that it’s a corner now, because the control handles are not in line with one another.

It’s not a sharp as a corner with 2 flat line segments, but more so than if it were a smooth point.

*Changing point types*

When I first started messing with point editing, I didn’t understand why when I moved a blue control handle it sometimes moved the curve on both sides of my point, sometimes just on one side. And I couldn’t figure out how to change that. It used to drive me CRAZY, until I learned how to change the point type. By changing a smooth point into a corner or a corner point into a smooth, you gain control over how you adjust the curved line segments coming off that point.

To turn a corner point into a smooth one, select it and choose Smooth. Doing that makes it easier to adjust a continuous curve so that it doesn’t have sharp edges that poke out.

If a point is smooth, you can make it a corner by selecting the point and then clicking Corner. You use a corner any time you want to change direction with your line or have independent control handles for the curves on each side of the point. The latter is the primary reason for making a smooth point into a corner point.

Let’s look at some examples.

#### A smooth point connecting 2 curved segments

I can change this smooth point to a corner so that I can move the blue control handles separately instead of in tandem. That means I can adjust each curve separately. I’ve adjusted the one on the left more than the one on the right.

#### A smooth point connecting 2 flat segments

You might think there’s not much point in turning a smooth point into a corner, because by it’s very nature it already acts like a corner. If I moved it at all, the line segments coming off it would automatically be on different trajectories.

But it does make a difference.

Let’s back up to where it was when we started. While it’s a smooth point, let’s say I turn that flat segment into a curve. Notice I get 2 blue control handles.

Let’s back up again, and instead, let’s turn that point into a corner first and then change it to a curve. This time, I only get 1 control handle.

That helps us create and control curves in different ways depending on what we’re trying to accomplish.

#### A smooth point connecting 1 flat and 1 curved segment?

You aren’t normally to have a smooth point connecting 1 flat segment and 1 curved segment. It’s not possible for them to be on the same trajectory or a continuous curve. Let’s think that through with some samples.

If you have a smooth point connecting 2 curves…

…and then make 1 segment flat, **the point automatically changes to a corner point**.

Why? Because they can’t really stay on the same trajectory.

If you have a smooth point connecting 2 flat segments…

…and click Make Curve to change one to a curved segment, the segments actually BOTH change to curves.

Why? Because a smooth point can’t have just 1 curve coming off of it — that wouldn’t fit the definition of a smooth point.

Since you aren’t usually going to have a smooth point connecting 2 different types of line segments, you normally don’t have a need to turn it into a corner. There is 1 case where you’d see a point connecting 1 flat and 1 curved segment. It’s a bit of an oddball that I’ll go over in the next section.

#### A corner point connecting 2 curved segments

This is that corner point we created earlier. You can see 2 blue control handles that aren’t in line with one another. That’s a big clue that it’s a corner, so keep your eye out for that. (But don’t forget, you can always select the point and look in one of your 3 areas to see what kind of point it is).

If you select Smooth, both the line segments stay curved, but your blue control handles are now linked. That means they are aligned and will move in tandem. Before I could move the left one a large amount and the right one a small amount, and they could go in different directions. Now, when I move the left one down the right one automatically goes up because on a smooth point, the curves are linked.

#### A corner point connecting 2 flat segments

If you select Smooth on this type of corner point, it will appear that nothing happened as it will look just as it does above. But it actually did change something. If next I choose Make Curve, my point is now a smooth point along a continuous curve. You see both line segments change into curves and you gain 2 blue control handles that are along the same trajectory with one another. Since they are connected now, they’ll move in tandem.

Let’s back up a moment and start with that corner connecting 2 flat segments again. But this time, let’s use a different order. We first choose Make Curve. This time you see just the highlighted segment curve while the other one remains flat. That’s because it’s still a corner point.

I could then choose Smooth to curve the other segment along a continuous curve. Here’s what’s different: the unhighlighted line segment that’s coming off that point does not APPEAR to be affected, but it is. It becomes a curve — the extra blue control handle tells you that — but it does not move so it still looks flat. Here’s how it looks.

And this is one of the instances where you might get a smooth point connecting a “flat” and a curved segment, which means you have a point that’s supposed to have a blue control handle but doesn’t. We’ll get to that in this next section.

#### A corner point connecting 1 flat segment and 1 curved segment

What happens when you change this type of corner to Smooth depends on which segment (highlighted) is selected with that point. That’s because there’s a specific, one-way sequence of the points.

Think back to when we were deleting points. We saw that after we deleted one, the selection automatically moved to the next point. If we kept hitting the deleting key, we kept moving point by point around the shape in the same direction. That’s what I mean by the sequential direction of the points. It’s not always clockwise or counterclockwise, but there is a way to predict the direction.

When you have a point selected, it highlights the line segment on just one side of the point. That’s giving you the clue for the direction. The selected point is the beginning of the line segment, while the point on the other end is the end of the segment. When you delete the selected point (so the beginning point), it’s the point on the other end of the highlighted line segment (the ending point) that becomes the next one selected. And it continues going on around the shape in that same direction, moving point to point.

Let’s look at some scenarios so I can show you how this works when you’re turning that corner into a smooth point.

##### Scenario 1: Selecting the corner point highlights the flat segment

In this case, that corner point is the beginning of a flat segment. When I click Smooth, because we have a curve on the opposite side of the selected point (notice the blue control handle), the that highlighted segment visibly changes into a curved segment and I can see the second blue control handle.

Because it was flat before we did anything, it’s easy to see the change when we turn that corner point into a smooth point. Remember: on a smooth point, the segments on each side have to follow the same general direction. That lower left point is a prior point in the order. If you started there and began tracing the shape with your finger, it would naturally want to continue on a curved trajectory. That’s why the highlighted segment is easy to spot as now being a curve.

##### Scenario 2: Selecting the corner point highlights the curved segment

Now it’s flipped – we’re coming at it from the other side. The selected corner point this time is the beginning of a curved segment. Because we’re starting with something different, we’re going to get a different result. When we change the point from corner to smooth, it doesn’t seem as if anything happened. But it did. We can see that an extra blue control handle is there now, so we know that point has a curve on each side and that the blue control handles will move in tandem.

But if it’s a smooth point now, why does that left-hand segment still look flat? That’s not a huge problem, because when we move either of the blue control handles, we’ll see that it curves.

##### Here’s the tricky part

Let’s click on that upper left point now. That one is prior in order to the one we’ve just been playing with. There’s no control handle and my right click menu is telling me it’s a flat segment. Am I going crazy?

Nope. The 2 points on the ends of this line segment are arguing over if the segment is flat or curved. (Ya, that isn’t real — just trying to explain it more easily). The lower left one says it’s curved, so when you select that point you see the blue handle. The upper left one says it’s flat, so that what it tells us in the right click menu and it refuses to give us a control handle. UGH! Just like arguing children. **This is where you can get a smooth point connecting 1 curved and 1 flat segment, or a corner point with a curved segment that has no blue control handle.**

Even if I change that upper left point to Smooth, it still doesn’t have that blue control handle to work with the curve. That means I can’t alter the curved segment from that upper left point without doing something. Since that’s the point I have to choose to highlight that segment, I have to change it to a curve to get the blue square. That’s me as a parent, stepping in, making a decision and telling the children to play nice. I’m not sure there’s a good reason for the programming to be this way — it just is.

There’s one other way to get that blue control handle to show up on that upper left point. If I add a point along the segment , it’s a smooth curved point. Now I select that upper left point again and the blue box is there.

## Video

Now it’s time to see this in action. Here’s the video:

This is all very theoretical. But how would you use that on some real shapes? So far on my car I just made it look funny. In part 2 of this lesson, we’ll look at some examples of how altering line segments and point types can help change the look of some real designs.

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