I used to spend ages making elements to perfectly fill the spaces in complex botanical patterns. Then I learned to create custom art brushes and it saved so much time! Plus it felt like I was nurturing and growing my plant designs with brushes rather than generating shapes. Since then I’ve taught many designers to use the technique and they love it too. I’ve also branched out to animal brushes, such as fishes and octopus arms.
For this tutorial I’m going to create a simple flowering cactus, but the principles can be applied to a wide variety of subjects and layouts. I’ll run through the steps so you’ll be able to make your own custom brushes from scratch and use them to organically create designs super-fast. The technique is powerful yet simple, so just a basic working knowledge of Adobe Illustrator is all you’ll need to get started.
To begin, decide on the subject and make a list of the type of brushes needed. For a flowering plant the list might be branch, leaf, petal and stamen. For this project I won’t need the branches but I’ll make the cactus section and flower parts. Making one of each would work just fine, but I prefer to add some variety (just like in nature). For the main cactus section I’ll make three slightly different versions, which when combined with curvy brush strokes will make the plant look more natural.
Now it’s time to make some sketches to get an idea of the shapes. You might be tempted to make the shapes more dynamic by adding curvature, but when drawing to create brushes try to avoid this. Draw the brushes in a straightened out manner. The curves are added later when the brushes are used to make strokes. If the original object is too curved it will make the brush difficult to apply accurately.
In the next step I’ll be creating these shapes in Illustrator. I’ll draw some of them in the software, but I’d also like to include some hand-drawn inky elements too (this is optional). I’ll add them in black ink over the top of my pencil sketch. I’m using a Pentel Brush Pen so I can get variable width lines and make droplet-shaped marks.
Scan (or photograph) the sketch so that it can be used it in the next step.
From Illustrator’s File menu Place the sketch. Use the pencil sketch as a guide to make the main shapes. There are several tools for making shapes, but I generally use the vector plotting pen tool (keyboard shortcut P). Just drop points down and drag out where a curve is needed. The points and curves are also fully adjustable afterwards. (An alternative could be to make the main shapes in the Adobe Draw app on iPad. The app has a sharing option to open in Adobe Desktop Apps, which allows the file to be sent to Illustrator on another device.) Fill the shapes with black or grey for now.
I could already head to Step Three from here to make brushes from these shapes. But I want to give you some extra tips on making more organic-looking plants with inky details, highlights and shadows.
To add highlight and shadow to the sides of my shape I’ll duplicate the main shape on top of itself, change it to a different grey, and then use the Eraser tool (keyboard shortcut E) to remove the unwanted area leaving just the highlight or shadow section.
Now I’ll use the Image Trace feature in Illustrator to turn the black inky marks on my sketch into vector shapes. (This technique can also be used on drawings made in pixel-based iPad apps like Procreate). I’ll select the sketch and bring it to the front. When I select my sketch the Image Trace button with presets dropdown appears in the top bar (if not, access the full Image Trace panel via the Window menu). I’ll trace using the Sketched Art preset, click Expand and ungroup the shapes.
I’ll match the grey of my wavy line details to the shadow and highlight. I’d like the droplet shapes to be a very light tone.
At this point you are probably wondering about colours. Brushes can absolutely be colourful. If you want to make multi-colour brushes then go for it. If you don’t actually feel the need for multiple colours in one brush, going monochrome does offer some benefits. Greyscale brushes are simple to colourize by changing the stroke colour. This allows the same brush to be applied in various hues. I’ll use this option for my brushes.
Check that the artwork is lined up really straight: vertically or horizontally is fine. The important thing is to avoid them leaning on a diagonal because this affects painting accuracy. Select the artwork to be made into a brush then click the new icon at the bottom of the Brushes panel (if you can’t see it use the Window menu to open Brushes).
For new brush type, choose Art Brush and then more options will appear:
Click OK and your very own custom art brush appears in the panel for use! Settings can still be altered: to edit simply double click on the brush in the panel. If you have multiple elements in your project, repeat this step to create a brush for each element. Move the brush artwork off to the side and deselect it before using the brushes.
First I’ll prepare a colour palette with several greens, pinks and a tiny bit of yellow for the plant, plus some neutrals and muted tones for the surroundings. Mix colours in the Swatches panel by clicking the new icon and moving the sliders.
I’ll use the Paintbrush tool (keyboard shortcut B) to apply the plant brushes. Personally I like to have my Paintbrush set to maximum smoothing (access the settings by double-clicking the Paintbrush icon in the Tools panel), and sometimes I’ll also use the Smooth tool afterwards as well.
I’ll paint my main cactus shapes to form the plant. For positioning it’s helpful to have a base from which to grow the plant (for example a simple plant pot shape). To make the plant look more natural I’ll alternate between the three different cactus brushes in the Brushes panel list. If a shape doesn’t look quite right in that position I’ll try a different brush or paint over to make a different curve. With my colorization settings I can apply stroke colours to the brushes. I’ll use darker colours for the sections that are further behind to give a sense of depth. To change how the sections sit in front and behind one another use the Arrange options found in the Object menu.
I’ve also used the Layers panel as a convenient way to arrange different elements of the illustration. The plant pot goes on a layer above so that the plant appears to be inside the pot (I couldn’t resist making my pot pretty by adding a mandala). A coloured square for the background goes on a layer right at the bottom of the stack. Layers also make it easy to lock parts of the illustration (with the padlock checkbox).
To create the flowers I’ll stack brush strokes of deep pink petals, yellow stamen, bright pink petals and green sepals into various mini compositions. Since the flowers are small I’ll zoom right in to work on them.
I can quickly and easily create many different versions of the little flowers using the simple black brushes with stroke colours applied.
This step is optional but useful if you want to share finished artwork, scale artwork or convert the brushes to solid shapes in order to alter fine details in the piece. Once expanded the brush strokes can’t be edited in the same way as before, so be sure to save a duplicate before expanding so you still have the option to go back to the brushes version.
On the duplicate file, unlock all the layers containing brush strokes, select all the strokes and simply go to the Object menu and choose Expand Appearance.
The brush strokes are converted to solid shapes. It’s now possible to go in with shape editing tools, such as the Eraser, and make modifications to the structure. This kind of editing can’t be done until the brushes are expanded.
So that’s it! Thanks for reading. I hope you enjoy the power and fun of custom art brushes in your own designs.
(For more on this technique take a look at my Botanical Brushes: grow a plant pattern in Adobe Illustrator class on Skillshare.)
Hi everyone! My name is Sue (a.k.a. Rocket & Indigo). I’m a surface pattern designer based near Liverpool in the UK. I like to mix graphic shape with hand-drawn line and inky detail, often in flowing layouts featuring plants and animals. I especially enjoy telling a little story through pattern.
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