How can I draw line drawings with the pen tool but with rounded edges?

Question

I understand how to draw shapes with sharp corners using the pen tool, but what I cannot figure out is how to draw shapes in line drawings with rounded edges.

For example here is my drawing in solid, sharp edges lines:

I would like to achieve something more like this:

Answer 1

If you only care about the outside corners, you could use the round corner in stroke settings.

This one is in Illustrator:

And this one is in Photoshop:

Like I said though, this will only make the outer corners round. The inner corners will still be sharp. The round corners stylize effect in illustrator is more versatile and controllable.

Answer 2

You can make circles, and place them on all the corners of the shape. Then edit the original path so that the corners don't show up anymore. Here's a quick little diagram of what I mean:

I don't find this a very reliable way to do it, however. What you need to use is Illustrator, or another vector based program. This is best for drawing shapes and symbols like this.

In Illustrator, it's really easy to do this. Just go to Effect> Stylize> Round Corners.

Answer 3

There is a quicker method than Blu's well documented version above. Though it's not quite as accurate (it's out by about 5.33%) it's certainly accurate enough to do small scale things.

1. Lay out your canvas first with guide lines for the shape you're going to draw:

2. Add the centre lines for the shape:

3. Add guides for the inner curve of the shape, assuming the diameter will be half the width of the line that will be made up by the shape, then further divide in half again, like so:

4. Draw your basic chamfered shape using the guides:

5. Select the **Convert Point Tool*:

6. Curve the two outside chamfered angles to the halfway point of the corner, like so:

7. Repeat the process for the inner curve, using the inner quarter guides:

8. The finished corner:

Note that earlier I said that this was an approximation. If you want it more exact, I found that working on a corner radius of 55.33% of the overall width of the line should be close enough to reproduce a reasonably accurate curved corner. So, if the thickness of the line to be drawn is, say 100 pixels, then you want to set your bézier curve guide at 55.33 pixels from the inner corner of the line. The version I've used above is only 50%, though should be good enough for quick reproductions.