Creating gradient mesh of complex shape
Let’s try to create a mesh of more complex shape.
Select the object, then go to Object > Create Gradient Mesh …
Damn! Controlling and coloring of such gradient mesh is out of the question. When we create a gradient mesh out of a rectangle, you usually do not encounter this strange behavior of mesh lines. Consequently, to obtain a well-controlled gradient mesh of a complex shape it is necessary that you create it by transforming a rectangular mesh. At the same time you can use all the available tools of transformation and selection, such as the Rotate Tool (R) and Lasso Tool (Q), for example. In the picture below you can see the stages of transformation of the rectangular gradient mesh using these tools.
Using this technique I created the smoke from the match in the tutorial Create a Burning, Vector Match Using Gradient Meshes.
How to avoid artifacts when coloring a gradient mesh
When coloring a gradient mesh there can appear different types of artifacts such as folds.
In order to avoid this kind of issue, make sure that that mesh lines do not intersect and are sufficiently far from each other.
Also avoid handles two adjacent points overlapping each other.
In order to achieve a smooth color distribution from point to point, try use other then Color panel, but also take colors directly from the already colored cells.
In conclusion, I would like to say that having enriched oneself with information from this article, you will still feel uncomfortable when working with gradient meshes, as this complex subject requires more in-depth study. Fortunately, you have an option to use the free Mesh Tormentor plug-in, which is designed to work with gradient meshes and fixes a lot of issues that may arise in your working process.