Illustrator CS5 Essential Training
Illustration by John Hersey

Using the Blob Brush and Eraser tools


Illustrator CS5 Essential Training

with Mordy Golding

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Video: Using the Blob Brush and Eraser tools

There are two unique drawing tools inside of Illustrator, one here called the Blob Brush tool. The other one here is called the Eraser tool. And they're both unique in that they are kind of performing these Pathfinder functions behind the scenes for you as you draw. Before we learn how to use these tools let's take look at some of their settings because as we'll find out they're really based in the same technology and they are quite similar. So I am going to start by double clicking here on the Blob Brush tool to bring up the Blob Brush Tool Options dialog box. You know I'll be honest with you. I am not a big fan of the name Blob Brush.
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  1. 3m 35s
    1. Welcome
      1m 18s
    2. What is Illustrator CS5?
      1m 46s
    3. Using the exercise files
  2. 12m 37s
    1. What are vector graphics?
      6m 3s
    2. Path and appearance
      3m 42s
    3. Stacking
      2m 52s
  3. 32m 6s
    1. The Welcome screen
      2m 23s
    2. Creating files for print
      6m 7s
    3. Creating files for the screen
      2m 55s
    4. Using prebuilt templates
      2m 40s
    5. Adding XMP metadata
      4m 18s
    6. Exploring the panels
      6m 33s
    7. Using the Control panel
      3m 11s
    8. Using workspaces
      3m 59s
  4. 43m 44s
    1. Navigating within a document
      9m 15s
    2. Using rulers and guides
      7m 26s
    3. Using grids
      3m 6s
    4. Using the bounding box
      3m 37s
    5. Using Smart Guides
      5m 56s
    6. The Hide Edges command
      3m 22s
    7. Various preview modes
      3m 47s
    8. Creating custom views
      4m 3s
    9. Locking and hiding artwork
      3m 12s
  5. 28m 46s
    1. Using the basic selection tools
      8m 50s
    2. Using the Magic Wand tool
      5m 22s
    3. Using the Lasso tool
      2m 28s
    4. Selecting objects by attribute or type
      3m 37s
    5. Saving and reusing selections
      2m 15s
    6. Selecting artwork beneath other objects
      2m 13s
    7. Exploring selection preferences
      4m 1s
  6. 1h 16m
    1. The importance of modifier keys
      1m 52s
    2. Drawing closed path primitives
      11m 38s
    3. Drawing open path primitives
      5m 47s
    4. Understanding anchor points
      3m 43s
    5. Drawing straight paths with the Pen tool
      7m 37s
    6. Drawing curved paths with the Pen tool
      9m 47s
    7. Drawing freeform paths with the Pencil tool
      5m 33s
    8. Smoothing and erasing paths
      3m 8s
    9. Editing anchor points
      7m 21s
    10. Joining and averaging paths
      10m 9s
    11. Simplifying paths
      4m 55s
    12. Using Offset Path
      2m 17s
    13. Cleaning up errant paths
      2m 32s
  7. 48m 26s
    1. The Draw Inside and Draw Behind modes
      7m 34s
    2. Creating compound paths
      5m 56s
    3. Creating compound shapes
      8m 0s
    4. Using the Shape Builder tool
      10m 28s
    5. Using Pathfinder functions
      8m 6s
    6. Splitting an object into a grid
      1m 16s
    7. Using the Blob Brush and Eraser tools
      7m 6s
  8. 49m 1s
    1. Creating point text
      4m 2s
    2. Creating area text
      8m 13s
    3. Applying basic character settings
      7m 44s
    4. Applying basic paragraph settings
      4m 24s
    5. Creating text threads
      8m 25s
    6. Setting text along an open path
      6m 29s
    7. Setting text along a closed path
      6m 24s
    8. Converting text into paths
      3m 20s
  9. 18m 55s
    1. Create a logo mark
      11m 26s
    2. Add type to your logo
      7m 29s
  10. 42m 42s
    1. Using the Appearance panel
      8m 21s
    2. Targeting object attributes
      4m 42s
    3. Adding multiple attributes
      4m 25s
    4. Applying Live Effects
      5m 18s
    5. Expanding appearances
      4m 42s
    6. Appearance panel settings
      4m 33s
    7. Copying appearances
      4m 51s
    8. Saving appearances as graphic styles
      5m 50s
  11. 34m 0s
    1. Applying color to artwork
      5m 57s
    2. Creating process and global process swatches
      8m 54s
    3. Creating spot color swatches
      3m 19s
    4. Loading PANTONE and other custom color libraries
      4m 49s
    5. Organizing colors with Swatch Groups
      3m 31s
    6. Finding color suggestions with the Color Guide panel
      4m 24s
    7. Loading the Color Guide with user-defined colors
      3m 6s
  12. 50m 23s
    1. Creating gradients with the Gradient panel
      8m 12s
    2. Modifying gradients with the Gradient Annotator
      4m 37s
    3. Applying and manipulating pattern fills
      5m 33s
    4. Defining your own custom pattern fills
      9m 13s
    5. Applying basic stroke settings
      5m 22s
    6. Creating strokes with dashed lines
      3m 41s
    7. Adding arrowheads to strokes
      2m 45s
    8. Creating variable-width strokes
      4m 35s
    9. Working with width profiles
      2m 36s
    10. Turning strokes into filled paths
      3m 49s
  13. 32m 46s
    1. Creating and editing groups
      8m 18s
    2. Adding attributes to groups
      12m 17s
    3. The importance of using layers
      5m 9s
    4. Using and "reading" the Layers panel
      7m 2s
  14. 12m 13s
    1. Creating and using multiple artboards
      7m 52s
    2. Modifying artboards with the Artboards panel
      2m 2s
    3. Copy and paste options with Artboards
      2m 19s
  15. 31m 10s
    1. Moving and copying artwork
      3m 55s
    2. Scaling or resizing artwork
      6m 47s
    3. Rotating artwork
      2m 44s
    4. Reflecting and skewing artwork
      2m 34s
    5. Using the Free Transform tool
      2m 15s
    6. Repeating transformations
      3m 39s
    7. Performing individual transforms across multiple objects
      2m 10s
    8. Aligning objects and groups precisely
      4m 27s
    9. Distributing objects and spaces between objects
      2m 39s
  16. 35m 40s
    1. Placing pixel-based content into Illustrator
      5m 14s
    2. Managing images with the Links panel
      4m 49s
    3. Converting pixels to paths with Live Trace
      8m 44s
    4. Making Live Trace adjustments
      6m 9s
    5. Controlling colors in Live Trace
      6m 4s
    6. Using Photoshop and Live Trace together
      4m 40s
  17. 14m 42s
    1. Managing repeating artwork with symbols
      4m 38s
    2. Modifying and replacing symbol instances
      3m 8s
    3. Using the Symbol Sprayer tool
      6m 56s
  18. 16m 57s
    1. Cropping photographs
      1m 59s
    2. Clipping artwork with masks
      3m 22s
    3. Clipping the contents of a layer
      3m 31s
    4. Defining masks with soft edges
      8m 5s
  19. 25m 52s
    1. Defining a perspective grid
      7m 48s
    2. Drawing artwork in perspective
      8m 46s
    3. Moving flat art onto the perspective grid
      9m 18s
  20. 25m 8s
    1. Printing your Illustrator document
      3m 26s
    2. Saving your Illustrator document
      6m 39s
    3. Creating PDF files for clients and printers
      7m 30s
    4. Exporting Illustrator files for use in Microsoft Office
      1m 4s
    5. Exporting Illustrator files for use in Photoshop
      2m 31s
    6. Exporting artwork for use on the web
      3m 3s
    7. Exporting high-resolution raster files
  21. 2m 18s
    1. Additional Illustrator learning resources
      1m 36s
    2. Goodbye

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Watch the Online Video Course Illustrator CS5 Essential Training
10h 37m Beginner Apr 30, 2010

Viewers: in countries Watching now:

In Illustrator CS5 Essential Training, author Mordy Golding explains the core concepts and techniques that apply to any workflow in Illustrator, whether designing for print, the web, or assets for other applications. This course includes a detailed explanation of the elements that make up vector graphics—paths, strokes, and fills—and shows how to use each of the Illustrator drawing tools. Also demonstrated are techniques for combining and cleaning up paths, organizing paths into groups and layers, text editing, working with color, effects, and much more. Exercise files accompany the course.

Topics include:
  • Setting up a new document based on the output destination
  • Using rules, guides, and grids
  • Making detailed selections
  • Drawing and editing paths with the Pen and Pencil tools
  • Creating compound vector shapes
  • Understanding the difference between point and area text
  • Applying live effects
  • Creating color swatches
  • Transforming artwork with Rotation, Scale, and Transform effects
  • Placing images
  • Working with masks
  • Printing, saving, and exporting artwork
Mordy Golding

Using the Blob Brush and Eraser tools

There are two unique drawing tools inside of Illustrator, one here called the Blob Brush tool. The other one here is called the Eraser tool. And they're both unique in that they are kind of performing these Pathfinder functions behind the scenes for you as you draw. Before we learn how to use these tools let's take look at some of their settings because as we'll find out they're really based in the same technology and they are quite similar. So I am going to start by double clicking here on the Blob Brush tool to bring up the Blob Brush Tool Options dialog box. You know I'll be honest with you. I am not a big fan of the name Blob Brush.

It sounds too close to blah, but in reality when you start working with this brush it's anything but blah. I want to focus here on the bottom here where it says Default Brush Options because you'll see here that you have the ability to set a size for your brush. But you can also choose different options for the brush itself. Now I'm using a Wacom tablet here with a pressure-sensitive pen. So I can set the size of my Blob Brush to take the pressure of my pen into account when I draw. I can also choose a variation for how much I want that pressure to affect the size of the brush itself.

For example, to understand how this preview works, I've currently specified the brush size of 10 points. It's a rounded shape right now. So I see a round 10 point circle right here. However, because I specified a variation of up to 10 points, that means that as I press harder or a lighter on my tablet I can either have the tip of my pen to be almost 0 or up to 20 points in size. I am going to leave my brush set to a round brush here. Obviously the angle of a perfectly round brush has no visual difference, so I'm going to click OK.

Now when you are working with the Brush tool itself, the color that you draw with it is actually determined by your stroke color. So I am going to tap the X key on my keyboard to bring my stroke into focus. Notice now my stroke is actually now in the front. Same thing also here inside that the Color panel. And I'll choose like a dark green color. Now first I'll start drawing with the mouse. Because the mouse has no pressure sensitivity, as I click and drag I get one uniform stroke that's consistently 10 points in size.

However, now I'll pick up my Wacom pen and as I create a stroke I could vary the pressure so now that you can see I could have thin and thick areas as well. Now I mentioned before that the Blob Brush performs some type of Pathfinder functions in the background. And here's the real unique thing about working with the Blob Brush tool. I am going to jump into outline mode for a moment by pressing Command+Y and you'll see that I am now working with these filled shapes. That's because as I draw a stroke with the Blob Brush tool Illustrator expands it into a filled shape when I stop drawing the stroke.

So I'll toggle back to preview mode by pressing Command+Y and watch what happens now when I continue to draw over a certain areas. Like maybe I want to thicken up the area down here in the bottom so I am just going to simply go ahead now and kind of paint over these areas. Well, now if I go into Outline mode I'll see that Illustrator combined all those together. Basically as I would draw more strokes with the Blob Brush tool, Illustrator will automatically create a single shaped by uniting all those strokes together into one.

But Illustrator is using some intelligence to make that happen. For example, I am going to change now to a different color, a lighter green. And I'll start now adding some other color here as well. In this example you'll see if I go back into Outline mode that Illustrator did not combine those two together. That's because they're different colors. So when you're using the Blob Brush tool, as you continue to add strokes, Illustrator will combine like fill colors into one overall object but it won't do that for a different colors.

So back in Preview mode you can see how working with the Blog Brush tool can be very easy to work with and to draw with. Let me delete these shapes for example and draw something like a leaf. Once again I am using the Wacom pen for this. So I'll start off with a nice green color here and I'll create some kind of shape like this and then like that. Maybe I'll add some detail down the middle, add a few shapes like this. And then if I decide I want to fill in or add some kind of color, I could switch to a lighter green color and I might want to scribble this behind all these shapes.

So I'll actually press Shift+D to toggle into my Draw Behind mode and I'll simply go ahead and scribble some of this right here behind this. And notice how that gets added right there. Let me kind of fill that up just a little bit more. I don't want too many gaps there. But this is really one of the benefits of working with the Blob Brush tool because as I just click and drag, it's merging the colors that have the same fill and maybe I'll just go ahead right about over here and add a little bit more detail. Now that I am done with that, I'll press Shift+ D to go back to my regular Draw Normal mode.

Now inside of the Tools panel right next to the Blob Brush tool is the Eraser tool. If I double-click on Eraser tool, I'll see that the options are very similar to what I just saw inside of the Blob Brush tool. In fact for the size of my eraser, I leave it set to 10 points, which is the same that I had it as for the Blob Brush tool. I'll change the setting here from Fixed to Pressure and I'll set the Variation to 10 points as well and click OK. What this allows me to do is actually write or draw over these artwork to erase it.

So it's kind of like performing a subtract for this artwork. One of the really nice things that I like about working with the Wacom tablet, however, is that my pen has an eraser on one end and a drawing nib on the other. So if I go ahead now and I select my Blob Brush tool here and I start clicking and dragging to draw some artwork here, I could just flip my pen over and notice that Illustrator automatically turns it to the Eraser where I can now go ahead now and erase parts of those paths as well. So it mimics the exact same experience that I might have when working with traditional tools like a pencil and paper.

Just one thing I want to note about the Eraser is that obviously in this example I've been using it to erase paths that I've drawn with the Blob Brush tool [00:06:053.02] but the Eraser tool can really be used to erase almost any paths inside of Illustrator. In fact, sometimes you might find it easier to simply swipe across an object to erase it rather than to perform its distinct Pathfinder command. The Eraser tool also changes its behavior somewhat based on the selections that you've made. For example, right now I have nothing selected so if I choose my Eraser tool here and I click and drag through the middle everything in its path becomes erased.

However, if I press Undo and I hold down my Command key to temporarily access the Selection tool and I click on just the background right here, now if I click and drag through the middle only the artwork that was selected becomes erased. The artwork that was not selected doesn't get touched at all by the Eraser. It's almost as if that leaf right now was locked, but the light green background behind it was not locked. So even if you don't like the name of the tool itself, the Blob Brush tool, I think you'll find that you'll have a tremendous amount of fun actually using it.

Find answers to the most frequently asked questions about Illustrator CS5 Essential Training .

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Q: Despite clicking the rectangle icon on the toolbar, as shown in the video, the other tool shapes are not accessible in Illustrator. The rectangle is usable, but the star, ellipse, etc. are not, and do not appear anywhere in the toolbar. What is causing this problem?
A: These tools are grouped together, so to access them, click and hold the mouse for a second until the other tools appear. If that isn't happening, reset the Illustrator preferences file. To do so, quit Illustrator and then relaunch the application while pressing and holding the Ctrl+Alt+Shift keys. Once the Illustrator splash screen appears, release the keys and that will reset the preferences file.
Q: In the video “What are vector graphics,” the author states that if he creates a 1 inch x 1 inch Photoshop file at 300ppi image, there are 300 pixels in that image. Is that correct?
A: This statement is by the author was not totally correct. If the resolution is 300ppi, it means that there are 300 pixels across one inch, both vertically and horizontally. That would mean you'd have 90,000 pixels in a 1 inch x 1 inch image at 300 ppi.
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