Illustrator Tip: How to Avoid Problems while Creating Blend Objects

In our today's tutorial I will tell you about the technique, which will help you to avoid artifacts while using the Blend Tool in vector design. By following these simple rules, you can easily control the blend of any complexity.

You can download the source vector file for this tutorial

Illustrator Tutorial Details

• Program: Adobe Illustrator CS4 - CS6;
• Difficulty: beginner;

The Blend Tool - is a powerful feature of vector graphics that allows creation of smooth transition between the objects. While using the blend objects you can create glares, shadows, and complex color transitions. However, if the Blend Tool is applied to objects of complex form, then most likely you'll get different artifacts. The correction of these defects can take you a lot of time, and in some cases you'll even need to look up some alternative techniques, which can replace mismanaged blend object.

On the figure below two very simple forms are shown. Let's create blend from them.

Select the forms and go to the Object > Blend > Make or use the Cmd / Ctrl + Opt / Alt + B shortcuts.

As you can see, the blend object has two faults. First, the intermediate forms extend the shapes of the bottom form; second, you've got a "fold" as the objects have sharp corners. In practice, artifacts of the blend effect can look even worse.

And now let's check out how we can avoid similar problems on the example of a complex form. I think a hand print suits our purposes. The form consists of a couple of paths and one Compound path. Moreover, some paths have sharp corners.

All the objects were created with the help of the Pencil Tool (N), that's why they have a lot of extra points. It would be better, if you simplify the form, this will allow you to work much faster in future. To delete some extra points, go to the Object > Path > Simplify… and find the optimal ratio of parameters that insignificantly changes the form of our objects, but significantly reduces the number of points.

Here I want to note, that the use of the Simplify feature can form some knots as it is indicated on the figure below.

Such knots must be deleted with the Pen Tool (P).

Surely, if you create the form with the Pen Tool (P), you won't need to delete the extra points. I just consider the most complicated case.

And now let's round the corners of our forms. With the Pen Tool (P) create two new points on both sides of the corner point.

Select the corner point, and then convert it into the smooth one by clicking on the appropriate button on the Control panel.

While using this technique, round all the corners. As you understand, this is necessary to avoid such defects, as folds. And in general, it is much better when the objects consist of only smooth points.

Copy one of the forms and paste it to the front (Ctrl / Cmd + C; Ctrl / Cmd + F) (in my case it is the Compound path). Change the color of the upper form.

Select both Compound paths, and then create a blend object (Cmd / Ctrl + Opt / Alt + B). The secret is very simple - both objects merging into the blend have the same number of points; moreover, the paths have the same direction, which is also very important (the use of multidirectional paths can cause some artifacts). And now just move the points of the top object inside the bottom form with the help of the Direct Selection Tool (A). You shouldn't remove, or add new points to the paths, just move the points of the upper form and control their handles. If you still need to add new points, then add them symmetrically to both objects.

On some spots we will need to change the handle's lengths of one or more points. To do it with the help of the Direct Selection Tool (A) is very laborious work. It is much faster simply to select a couple of points, and then go to the Object > Transform > Scale… and reduce the Scale parameter. The value of 50% in most cases will work perfectly.

While working with the blend object, you frequently need to zoom in the artboard. If you work with a couple of blend objects, and they have large number of steps, then your application might be significantly slowed down. Therefore, during your work process it is desirable to establish a small number of specified steps (Object > Blend > Blend Options…).

While completing your work, you can set the number of steps that you consider right.

To select a couple of points you can use the Lasso Tool (Q). But you'll need to lock the bottom object.

However, it might cause some defects at the disappearance of the intermediate objects or the creation of "folds".

Don't worry; the artifacts will disappear after you unlock the bottom object.

Using the techniques described, I've created the ink blot, that looks like a handprint, and which consists of blend objects.

You can download the source vector file for this tutorial

You can notice a bit rough edges, which have some blend objects. Don't worry, that is the way the Blend effect is displayed in Adobe Illustrator. When you save your artwork in raster format, the edges will be absolutely smooth.