blob brush Tool for Illustrator Tutorial

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By Andrew Buckle, Updated : 2021

The blob brush in Illustrator is a powerful painting tool, one that can be combined with transforms, effects, color fills, and more

** Youtube video tutorial on blob brushes / blob brush tool in Illustrator and how to create amazing paint designs using this powerful tool **

1. Where is the blob brush Tool in Illustrator

The blob brush in Adobe Illustrator can be found beneath the paintbrush tool. Or access using shift+B as a shortcut.

blob brush icon in the toolbar in Illustrator

2. Basic Operation

Go to the paintbrush tool in the Adobe Illustrator toolbar (where the blob brush is located) and Select the second tool 'blob brush' and Set the color of the fill. The color can be a solid color. The color can be a gradient. Double click the icon of the blob brush to display the options. Apply blob brush to the art-board. Instead of stroke, the blob brush applies a vector fill. Select the vector design, the design is made up of multiple points. The result can be manipulated using the standard Illustrator tools, such as changing the opacity, changing the blending mode.

blob brush multiple colored designs wavy across the Illustrator art-board

3. Blob brush Options

Access the settings for the blob brush by double-clicking the brush icon in the toolbar. You can also press return.

blob brush panel with the options such as size, roundness etc

The panel offers 'Keep selected', 'Merge Only', fidelity, size, angle, and roundness, along with randomness and pressure settings. It is similar to the eraser tool. It is also similar to the basic Photoshop brush settings.


Two check-boxes are available. To keep the brush selected, check the Keep Selected button. If not, you can always select the path manually.


If merge only is turned off, any new brush strokes are added as new paths. If merge only is on, all brush strokes are combined. You can always use the pathfinder panel to unite the vector paths.


Fidelity allows for more accuracy but adds more points. Smoothness is less accurate but fewer points.


Set the size for the brush, it can be a thin line or a big bold brush stroke. Set the roundness for the brush to less than 100% to create an elliptical stroke, more akin to a calligraphic brushstroke. With roundness less than 100%, you can also angle the brush.

blob brush calligraphic design in brown

There are also a few additional options such as having a fixed size or introduce randomization and variation for the size (as well as angle and roundness) as well as settings for an art pad and pen combination. Click OK. It should be noted that the randomization is per brush stroke and not sadly during the actual application of each blob brush stroke. The randomization is limited to the size of the brush. Same for angle and roundness.

blob brush variations such as the pressure, randomization etc

4. Color fill for the blob brush / tool in Illustrator

The Illustrator's blob brush can be filled with solid colors such as yellow and red. Use a gradient for a special touch. Or a pattern. Color effects can also be added. The color can be changed at any time. Additional fills can be added via the Appearance panel

blob brush gradient strokes applied

5. Shift / straight line with the blob brush and zigzags

Hold down the shift key to apply the blob brush in a straight line. You can create multiple straight lines. Zigzags also, angle your strokes at forty-five degrees. Squares and rectangles, angle your strokes at ninety degrees. Many combinations of shapes such as lattices can also be created.

blob brush zigzag design using straight lines in Illustrator

6. Adding strokes to the blob brush stroke

As you add the artwork, you will only see the fill being added but you can always add a stroke on completion as well as other effects such as live effects / blurs / additional fills etc via the appearance panel. You can also then add width profiles to the blob brush.


Adding a path offset to the extra strokes for the blob brush

blob brush using strokes and appearance effects added to the design

Add a new fill for the blob brush and a transform to shift the new fill by 50pt

blob brush multiple fills added to the design via the appearance panel

Apply the blob brush and Keep selected and Go to the stroke settings and set color etc and Apply a width profile

blob brush width profiles added to the artwork

7. Use Blob brush with other paths

Depending on the selection set for the blob brush tool, you can merge with other paths already created (circles etc) and select path and select the Illustrator blob brush tool and double click to see the options to see that merge and selected are on Apply brush strokes to path such as circle.

NOTE: only merges when it is the same color ! So if you have a blue path, use a blue blob brush to merge

blob brush shadow effect added to the artwork and star burst design

You can control the merging by only merging with selected check set to on. You can also add the strokes and then add additional paths to that via the pathfinder combine / unite. You can also use the subtract to add perhaps add spots and dots to the artwork. You can also add them to symbols (in editing mode) and can find a lot of different symbols on this site for use with the tool. You can use the tool to create all kinds of unusual connection designs by holding down the shift to create straight lines

blob brush grid design created using the straight line feature

8. Blob brush and Excessive points

One main issue with the tool (whether accurate or smooth), a lot of points can be created unless you add a very basic stroke. You can always use the various tools such as simply etc to remove some of them (personally the best tool is Astute Graphics' VectorScribe plugin). If you haven't got this tool then perhaps use the object menu and path and simplify to reduce and cleanup the path

blob brush reduce anchor points etc

9. Randomization and blob brush

Sadly, the randomization and variation is not with the blob brush single operation but only on re-applying the brush so if you apply one stroke with a variation set to 20pt (and size 10pt) you will get a 30pt or perhaps 15pt etc but not within the actual path itself. The randomization actually works nicely with adding them as single spots (you don't have to add the tool as a long single stroke).

blob brush randomization

Go to the blob brush settings via the icon and set size to 90pt and set to random (to the right of the size). Set the variation to 40pt etc, obviously you can set the size and variation to different values. You can also use other settings as well such as pressure. See the image on the left for a variation of dot blob brush sizes added in blue and then in orange, you have small blobs added and larger blobs and a lot of variation in between

blob brush spotted effect added

It would be great if there was a randomization of color available as well but there is not though you always just change the color via the fill color in the toolbox as you add the artwork. You can also randomize the result by using the color guide tool.

10. Use the Illustrator blob brushes as a symbol or swatch etc

You can use the Illustrator blob brush strokes to create other presets.

blob brush multiple spots spread across the design

Simply add a blob brush and drag to the symbol panel and select item in the symbol panel and use with the sprayer tool.

blob brush as symbol designs in Illustrator

You can also do the same with the swatches if you wish to create a tile and you can use the tool in the pattern editor.

blob brush pattern artwork

The result can still be added to using the same features of the tool to merge the fill. With the latest release, if you add the artwork as a symbol preset then you can also now add it as a dynamic or static item and if added as a dynamic then you can use the artwork as a master and add color and strokes etc to the instances added to the art board.

11. Blob brush and repeat

You can also use the tool with the repeat feature that has been added to the recent release of Adobe Illustrator. You can use it with the radial option as well as grid and also mirror to create all kinds of amazing designs. You can increase the number of instances, you can change the distance of the blob brush strokes from the center, and much more. The blobs are still live. You can edit them by double-clicking the repeat object. Change the size, angle, color, etc of the design. Select 'Exit Selection Mode' to leave.

blob brush repeat feature

12. Blob / Eraser tool

Personally, not sure why the blob tool is not on the same toolbox as the eraser tool as it is the same tool but inverted. The eraser tool can be added across the applied blob brush stroke and break the art into new individual paths which can then be added to by additional strokes.

blob brush erase tool

13. Effects and the blob brush

Once you have added the blobs (and you can add them as actual spots or in one continuous stroke) you can add effects such as tweak or roughen or offset or glow etc and you can then expand the appearance via the object menu. Or add graphic styles

blob brush roughen effect added to the brown brush stroke artwork in Illustrator

14. Transforms and blob brush

The blob brush can be filled with nil, the stroke set to black and a quick transform applied to create a lovely zoom transform effect. Sadly, you can't add to the blob brush once you have added the appearance. Create the design and then apply the effect.

transform effect added to the stroke