Blob brush options and best practices

Last updated on Sep 11, 2025

Explore various Blob brush options and best practices to use the tool more effectively in the designs.

Double-click the Blob Brush tool in the Tools panel to set its options.

The Blob Brush Tool Options dialog box displays various options like Fidelity, Default Brush Options, and more.
Blob Brush Tool Options dialog box overview

Blob brush options

Function

Keep Selected

Keeps all paths selected as you continue to draw a merged path.

Tip

This option is useful for viewing all paths that are included in the merged path.

Merge Only with Selection

Specifies that new strokes merge only with the current selected path.

Fidelity

Controls how far you have to move the mouse or stylus before Illustrator adds a new anchor point to the path.

Size

Sets the brush size.

Angle

Sets the angle of rotation for the brush.

Roundness

Sets the roundness of the brush.



Blob Brush tool guidelines

Follow these guidelines while using the Blob Brush tool:

  • To merge paths, they must be adjacent in stacking order.
  • To merge Blob Brush paths with existing artwork, ensure that the artwork has the same Fill color and no Stroke, as the Blob Brush tool creates paths with a Fill and no Stroke.
  • To apply paint attributes (such as Effects or Transparency) to the Blob Brush tool, select the brush and set the attributes in the Appearance panel before drawing.
  • To merge paths created by other tools, ensure that the existing artwork does not have a Stroke. Then, set up the Blob Brush tool to have the same Fill color and draw a new path that intersects all the paths you want to merge.
  • To merge new paths with the topmost matching path encountered, ensure that the paths are drawn using the Blob Brush tool. If the new path touches more than one matching path within the same group or layer, all intersecting paths are merged.