Join Mike Rankin for an in-depth discussion in this video Modifying paths, part of Inkscape Essential Training.
- Let's explore some of the ways you can modify existing paths using commands in Inkscape's extension menu. The first thing to understand is that we're talking about paths, not shapes, so if you use one of the shape tools to draw, say an ellipse or a rectangle or a star, you're going to have to convert that first to a path before you can use the commands in the extensions menu. You can tell if you have an object or a path by selecting it and looking in the status bar. Right now this is a rectangle, it's not a path. So I can convert it to a path by choosing "path, object to path." Now it tells me it's a path with four nodes.
Okay, so what if I wanted to take this rectangular path with its perfectly straight sides and roughen them up so it looked like kind of a piece of wrinkled paper? Well first I need more than four nodes to work with. So with the path selected, I'll go to "extensions, "modify path, add nodes" and in the dialog I have the choice of a method and a number of nodes to add so I can tell Inkscape to add nodes so the longest segment is no longer than a specific value, maximum segment length here, or I can specify a number of segments to divide each existing segment into by choosing "number of segments." So I can say, "Divide each existing path segment "into five" by adding nodes, so that's what we'll do here.
We'll say number of segments, five. Click "apply," close the dialog and we can switch to the node tool and now we can see each side has been divided into five segments. Next, I'll roughen up this shape by going back to extensions and choosing "modify path, Jitter nodes." We can click on "Live preview" and this command randomizes the position of nodes within distances that you specify, maximum in terms of X and Y. You can also decide whether or not to shift node handles as well and remember, this is randomizing things so if you don't quite like the preview, you can just toggle it off and on and get an entirely different effect.
All right, that's good enough so I'll click "apply" and now we have our wrinkled piece of paper. Note down in the corner, this node got split so you might have a little work to do to patch nodes back up when you run this. Now as I said, there are many interesting ways to modify paths with extensions, but I want to show you one that's especially interesting, and that's called "Interpolate." It's found under "Generate from path" in the extensions menu and this is the command you can use in Inkscape to make blends of two paths. It can blend just the shapes of the paths or the shapes and the formatting.
So I'm going to go to the layers dialog and turn off the paper layer and turn on the interpolate layer so we can see how interpolate works. So here I have a pair of open paths which are really just squiggly lines but they're good for illustrating what interpolate does. So I'll take the selector tool and "shift + click" to select both of these paths, and go to "extensions, generate from path, "interpolate" and the dialog lets me turn on a live preview so I can see the effect. So right away I'm seeing the shapes are blending but not the formatting.
If I want to blend the colors, I can select "interpolate style" as well and I can see that five steps have been created and the end paths are going to be duplicated. Let's increase the number of steps and see what we get. We'll go from five to 20, and we get more intermediate steps. You can use the exponent value, to gather steps on one side or the other of the blend, so a positive value will make the steps clump on the right side. A negative value will make them clump on the left and zero makes all the steps equally spaced.
Okay, let's try another example. I'll click "apply" and switch to the other exercise file for this lesson. So in this file, there's a monkey hanging from a tree branch and right now it has a very simple cartoony look with lots of flat areas of color. But we can create transitions from one color to another with interpolate. For example, let's zoom in on the top leaf right up here, I'm just going to select it and press the "3" key to zoom way in, and it has one main dark green object and a smaller lighter green object for the highlight and I can blend these two objects with interpolate.
So I'll click once and make sure I have this dark green object by checking the fill color and then I'll "shift + click" to select the second one and this is key, the order of selections when you're using interpolate. The stack of interpolated objects will go from the first object I click on to the last so I have to click on the big green object first and then the smaller light green one, otherwise I won't see the blend. It'll be covered up by the biggest object. So always click the largest one first. Then with these two objects selected, I'll choose "extensions, generate from path, "interpolate," and let's try 20 steps, make sure we select "interpolate style." We'll turn on the preview and right away we can see the blend.
I'll click "apply" and close the dialog. Now the new group of interpolated objects is created on top of everything else so let's use the controls to lower it down a couple times and there you see the blended effect. So in this movie, we looked at just a few of the many ways you can modify paths with the commands in the extensions menu. We saw how to add nodes and then move them to change a plain rectangle into a roughened shape that looked like a piece of paper, and we saw how to use the interpolate command to create blends between pairs of open paths and filled objects to create effects you can't achieve any other way in Inkscape.
- Downloading and installing Inkscape
- Creating new documents
- Importing AI and EPS files in Inkscape
- Working with input devices like tablets
- Drawing basic shapes
- Scaling and rotating objects
- Adding fills and strokes
- Using Inkscape extensions
- Adding and editing text
- Printing and exporting Inkscape artwork