Blob brush Tool for Illustrator Tutorial
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. This is a detailed tutorial on the Illustrator blob brush tool in Adobe Illustrator CC 2021 2020 2019 etc
1. Where ?
The tool can be found beneath the paintbrush tool. Or access using shift+B as a shortcut.
2. Basic Operation
Go to the paintbrush tool in the toolbar and Select the second tool and set the color of the fill. The color can be a solid color. The color can be a gradient. Double click the icon to display the options or press return. Apply stroke to the art-board. Instead of stroke, the tool applies a vector fill. Select the vector design, the design is made up of multiple points. The result can be manipulated using the standard tools, such as changing the opacity, changing the blending mode.
Access the settings by double-clicking the brush icon in the toolbar. You can also press return. 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 stroke settings.
4. Check box settings
Two check-boxes are available. To keep the path selected, check the Keep Selected button. If not, you can always select the path manually. If merge only is turned off, any new 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 tool, it can be a thin line or a big bold stroke. Set the roundness to less than 100% to create an elliptical stroke, more akin to a calligraphic stroke. With roundness less than 100%, you can also angle the brush.
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 stroke and not sadly during the actual application of each stroke. The randomization is limited to the size of the tool setting. Same for angle and roundness. 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.
6. Color fill for the tool
The generated path 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
7. Shift / straight line and zigzags
Hold down the shift key to apply the tool 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.
8. Adding strokes to the 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 path. You can also add effects such as as offsets You can also add loads of new fills and add transformation effects to move the fill to a different position or simply use blending modes to blend the colors as well as the strokes etc. Apply the tool and Keep selected and Go to the stroke settings and set color etc and Apply a width profile
9. Use with other paths
Depending on the selection set for the tool, you can merge with other paths already created (circles etc) and select path and select the tool and double click to see the options to see that merge and selected are on Apply 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 stroke to merge. 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
10. 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
11. Use as symbols etc
You can use the strokes to create other presets such as symbols as well as swatches Simply add a path via the tool and drag to the symbol panel and select item in the symbol panel and use with the sprayer tool. 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.
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.
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 strokes from the center, and much more. The spots 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.
14. Eraser tool
Personally, not sure why the 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 brush stroke and break the art into new individual paths which can then be added to by additional strokes.
Once you have added the artwork (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
The paths 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 artwork once you have added the appearance. Create the design and then apply the effect.
Examples of the fills applied across the art board with different colors and strokes added
Panel for the tool, you can set the size and angle and roundness etc as well as keep selected etc
You can change the roundness of the artwork and then you can change the angle.
You can use the panel to set the randomization and this is applied per stroke
You can fill the lines with gradients such as linear ones as well as radial and faded ones
Use the shift key to control / constrain the angle to create zigzags etc
Effects can be added such as offsets to create all kinds of unique designs from a single stroke
One of the key panels being the powerful appearance panel to add additional fills etc
You can add strokes and width profiles to the artwork
You can join the lines and paths using the powerful features of the tool
You can use the tool to quickly create grids etc
You can use the simplify command to reduce the number of points
Random size of the designs
Multiple spots of differing size are super easy to create
You can add any of these vector designs to the symbols panel
You can apply the results of the tool as a symbol and spray the design
You can use the repeat feature to make all kinds of designs
Use the repeat radial feature for all kinds of amazing artworks
The strokes can be erased using some of the tools of the application
You can apply effects such as roughen to the lines
You can use live effects and transforms and more to create all kinds of designs