Monday, November 17, 2008

How to make smooth curved lines

One of the most frequently asked questions about photoshop is “how do I make a simple, smooth curved line?”. If you’ve got a tablet, there might be other ways, but with a mouse it can seem a little tricky. The brush and pencil tools are too “jerky” so those are no good. The pen tool is the answer, but to many it’s unintuitive. So I thought I’d pass along my technique. Hopefully it’ll help someone out there.

The end goal is something like:
final curve

Nothing fancy, but nice and smooth.

I have a feeling this process is going to sound more complicated than it is. Do it once though, and it’ll be a piece of cake after that.

First, the tools we’ll use:
toolbar

Take special notice of the direct select tool. There are two arrows under there. The solid black one (path selection tool) lets you move a path as a single unit. The white one (direct select tool) lets you modify a path. This is the one we want right now.

Step 1
Define what you want the line to look like. I wanted a smooth 3px line. I like the brush for such things. Choose the brush tool and have a look at it’s options, and palette:
brush options
brush options palette

My settings show a simple 3px brush - but you can go crazy here (and get some interesting effects ultimately).

Notice! We’re not doing anything with the brush tool - we’re just setting it up - no drawing!

Step 2
Select the Pen tool. (This is by far my favorite tool in PS). You want to draw a path (not a shape) so get your pen toolbar looking like this:
pen options

Now, create a start and end point on your canvas by clicking twice (or make a few points - whatever strikes you)
start curve

Step 3
Select the direct selection tool (the white arrow, not the black one!). Right click anywhere on your curve. From the pop-up menu choose add anchor point. This will put a point on the line. Now, (still with the same tool) click and drag that new point. This is the basis for all pen-related actions. You created an anchor point that has two handles.
bent curve

You can drag the point around, as well as the handles. Mess with them a bit to see what you end up with.

Add a second (3rd, 4th whatever) anchor point and move the anchors and handles around. I ended up with this:
final curve

Step 4
Create a new blank layer:
layers palette

So you’ve got a curve you like - here’s the magic part. Go to the paths palette:
paths palette

There’s the path you just created, called work path. Right click on that layer and choose Stroke Path. You’ll get a pop-up box:
stroke path

From there you can choose to create your stroke from any number of items (pencil, brush, healing brush etc). In step one we set up our brush the way we wanted it. So choose brush. Click Ok. It’ll look something like:

stroked curve

To get rid of the path line, just deselect the work path in the paths palette (click anywhere in the palette).

That’s it!

final curve

It’s worth mentioning that the final colored path was put on that new layer you created. It will not be modified by changing the path!. To change your line, delete the layer you put the stroke on, go back to your path, reshape it, then reapply the stroke. It’s easier than it sounds. In fact this whole process of creating a curved line just takes a few seconds - it just might look complicated.

Go forth and be smooth and curvy.

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