In lesson 2 you learned that there are two types of objects; simple objects and path objects. We explored simple objects in lessons 1 and 2. In this lesson we will learn to create and edit path objects using the drawing tools available to us in Expression 3. Let's take a look at these tools before we examine just what a path object is.

The Drawing Tools

Expression has four drawing tools. When a drawing tool is selected, option buttons for that tool appear at the right end of the ToolBox. For all tools except the Freehand tool, the option buttons are Append and Do Not Append. These options allow you to start a new path from the end of another path, or not, depending on which option is chosen (more on this as we progress). With the Freehand tool, the options that appear allow for stylus pressure. Stylus pressure only works with skeletal strokes, not with plain or gradient strokes.

The Freehand tool and the Pen tool are located on and under the 3rd button in the top row of the ToolBox. The Freehand is the easiest tool to use and the Pen tool is the most difficult tool to learn. With the Freehand tool you just draw on the document window just like you would draw on paper with a pencil. If you want to get right down and technical about your drawing, you'll want to master the Pen tool.

The B-Spline and Polyline tools are on and under the 3rd button in the bottom row of the ToolBox. The B-Spline tool is another easy to use tool for creating smooth curves and lines. The Polyline tool is similar to the B-Spline tool but this tool makes sharp corners rather than curves. We will examine each tool in turn, but let's start with understanding what a path is before we learn how to make one.

Anatomy of a Path

A path is a trail of segments joined together by nodes. Nodes can be thought of as tiny, multi-purpose connectors which define a portion of the segment on either side of that node. The connector defines such things as whether the segment leading away from that node should be a continuation of the segment leading into it, or whether there should be a break so that a sharp corner is created rather than a smooth curve. The beauty of paths is that a path can be changed after it is created because paths are not "glued to the page" liked pencil strokes are glued to paper. A smooth path can be converted to a path with sharp corners, and sharp corners can be converted to smooth paths. You can change a sharp corner to a cusp, where the segment leading into a node is sharp and the segment leading away from the node is curved, and vise versa. In addition, unlike other drawing software, Expression gives you the ability to create different types of curves; Bezier and B-Spline.

A Bezier curve is a curve where the node is attached directly to a path while a B-Spline curve is described by a node that is not attached. Below is an example of Bezier curves.

Figure 1 - An example of Bezier curves.

Notice the small squares at the beginning and end of the path as well as in each place where the path curves. These are nodes. In a Bezier curve, the nodes contain tangent handles which look like lines that extend on one or both sides of the node. This type of curve is edited by adjusting the node itself or by adjusting the tangent handles on either side of the node. The following example illustrates a B-Spline curve.

Figure 2 - An example of B-Spline curves.

In this example, with the exception of the nodes at the beginning and end of the path, the nodes are not attached directly to the path and the nodes do not have tangent handles. B-Spline curves are edited by moving the nodes above or below the curve.

Notice, in both examples above, that the first node on each path has a plain node while the nodes at the right end of each path has an arrow and another strange object attached to it. The arrow indicates the direction of the path. The first click you make on the view area will always be the beginning of the path and the other end is the end of the path. The arrow simply shows you in which direction you drew the path. From the examples above you can see that I drew each path from left to right.

The other strange object at the same end as the arrow is the stroke width handle. It works like the Stroke Width meter on the Paint Style palette. Pulling on the stroke width handle away from the path will widen the stroke attached to the path and pushing towards the path will narrow the stroke.

The stroke width handle, and all nodes along a path, are adjusted with the Node Tool. A node must be selected to adjust it. Notice in the examples above that some nodes are hollow and some nodes are solid. Hollow nodes are deselected while solid nodes are selected.

Let's get a little hands on experience here. Click on the Freehand tool (third button in the top row of the Toolbox) and draw a squiggly line on the document window (view area). With the Freehand tool, a path begins at the point where you start to draw and ends when you lift the mouse off of the view area. Now click the shortcut letter n on your keyboard (to choose the Node tool) and approach the stroke width handle by the arrow at the end of your path (your squiggly line). Notice how the cursor changes to a cursor with a 'width handle' image below it, indicating that you are about to adjust the width of the stroke attached to that path. You can see that cursor in the image below:

Click on the handle and drag away from the path and notice that a ghost copy of the stroke width handle follows the cursor to show you the direction you are dragging. This is useful because you 'shear' a stroke if you drag at an angle rather that straight away from the path. More on that later. Here's what that ghost image looks like:

Look at the status bar as you drag. It will tell you the stroke width in points so you can drag to a precise width. Once you release the mouse, the stroke width is registered in the PaintStyle palette, on the stroke width meter, and your path reflects the new stroke width.

Notice that all nodes on the path above are solid, meaning that all of the nodes are selected. This is because the operation we just performed (changing the stroke width) affected all of the nodes on the path. Click on one node on the path and notice that all other paths become deselected.

More than one node may be selected at one time. To do this, click on a node and hold down the Shift key while clicking on other nodes to add to the selection. When more than one node is selected, any adjustments you make will affect all selected nodes.

Paths can be open or closed. An open path is a path where the beginning and the end of a path are in different locations. A closed path is one where the beginning and end of a path are in the same location. When you draw with any drawing tool, the cursor for that tool will change depending on the operation you're performing. For example, the Freehand tool looks like a pencil when you are drawing an open path, but as you move close to the beginning of a path, a small circle will appear to the right of the normal pencil cursor indicating that clicking at this point will create a closed path. We just saw an example where our node editing cursor changed to tell us that we were about to adjust the width of the stroke on our active path. You will learn to appreciate these helpful "road signs" on your way to making paths in Expresion 3.

We will work with editing nodes, and various operations associated with creating and editing nodes, a little later in this lesson. For now, let's take a look at the drawing tools. There is more to the Freehand tool than we've learned so far so let's start there.

The Freehand Tool

The Freehand tool, the third button in the top row of the ToolBox, displays a paint brush icon on it's ToolBox button (but the Freehand cursor is a pencil; go figure). The lowercase letter 'p' shortcut key cycles through all of the tools that occupy this space on the ToolBox (the Freehand, Pen and Bitmap Pen tools). With the Freehand tool, you simply draw a trail with your mouse or stylus where you want the path to be formed. The trail is fitted with Bezier curves to form the path. The tangent handles on a Freehand path won't be readily visible until you click on a node along the path with the Node tool. The Node tool, remember, is the tool you use to edit nodes on a path.

The Freehand tool works with a regular mouse as well as a stylus (pen mouse if you prefer). If you are fortunate to have a stylus, the options on the right side of the ToolBox give you the ability to vary the width and transparency of a stroke according to the pressure you apply when drawing. Notice the button with a swish icon which appears depressed in the screen shot on the left. This is the Variable Width on/off switch. If you use a stylus, pressing this button makes your Freehand tool pressure sensitive to the stylus. The more pressure you apply, the wider the stroke will be. The stroke becomes thinner as you lighten the pressure. The Variable Width button has no effect if you don't have a stylus or you aren't using it with the Freehand tool.

The meter to the left of this button is the Maximum Pressure Width meter. This meter corresponds to maximum pressure and sets the maximum width of a stroke. My meter is set to 80 pixels so the maximum stroke width using maximum pressure on my stylus is 80 pixels. If I reduce the value to 40, the maximum width of my stroke will be no wider than 40 pixels. Experiment to determine your preference. Expression will remember your setting with each launch until you change it.

The slider below the pressure width buttons allow you to control how much stylus pressure will apply to stroke width and how much it will affect stroke transparency. If, for example, you want a stroke to become more transparent with increased stylus pressure, move the bottom slider further to the right and the top slider further to the left. If you want stylus pressure to affect stroke width to a greater degree than it affects transparency, move the top slider further to the left and the bottom slider further to the right. These sliders affect bitmap strokes only. We will discuss the difference between bitmap and skeletal strokes in lesson 4, but if you want to experiment with the sliders, use the strokes in the Water strokes folder as these are bitmap strokes. See the discussion on The Stroke Palette below to learn more about accessing strokes in the Strokes palette.

When the Variable Width button is active, your settings will apply to all subsequent paths you draw but will not change an existing path. You can disable the Variable Width meter in which case both the Variable Width meter and sliders disappear.

As mentioned earlier, with the other drawing tools the options that appear at the end of the ToolBox are Append and Do Not Append which allow you to continue a previously drawn path, or not. Since there's no room on the ToolBox for these options with the Freehand tool you need to hold the Alt key to append (add) to a freehand path. Try this: choose the Freehand tool and draw a path on your document. Now move your cursor close to the beginning or end of the path. Nothing happens. Now hold press the Alt key and move your cursor to the beginning or end of the path again and notice that a little squiggly line appears next to the cursor. This indicates that the path you are about to draw will attach itself to the point of the existing path you're close too. Now draw and short path, release the mouse and notice that the new path attaches to the original path.

The Freehand tool also acts as a selection tool, regardless of the tool used to create the stroke, but only to a certain extent. You can select any path with the Freehand tool but only to make the stroke active. Say for example, you want a B-Spline path active to apply a new stroke color to it, or to delete it, but your currently active tool is the Freehand tool. Simply click on the B-Spline path with the Freehand tool and make your changes. No bounding box will appear on the selected path so you can't move, resize or rotate the path.

For people who don't have a stylus, or choose not to use it, you can achieve the same variable width and transparency effects using the Variable Width palette. Let's take a look at that next.

The Variable Width Palette

Open your Variable Width palette by choosing Window > Variable Width from the menu bar or by pressing the F7 shortcut key. The palette will dock itself with the other palettes on the left side of the screen. If the palette is minimized, click the "Restore Minimized Window" button to the left of the "Close" button to maximize the palette.

Figure 3 - The variable Width palette with a node added.

Click on the center node and drag it to the top of the graph and notice that the stroke in the center of your path got wider. Click on the center node again and this time drag it to the bottom of the graph and notice that the stroke got narrower this time. You can add more nodes using the + button and a new node will appear on the graph to the right of the currently active node. Like paths themselves, the nodes in the graph are hollow when deselected and solid when selected. You activate nodes on the Variable Width palette by clicking on them. Once active, you can delete nodes using the - (minus) button, slide the nodes back and forth along the graph, or move them up or down to widen or narrow a stroke along the active path.

The Variable Width meter comes with a set of variable width profiles, called presets. Click on the button to the left of the minus button, labeled Preset Profiles on the tool tip, hold down on the mouse as you scroll through the list, releasing the mouse when you reach the preset you want. Just for fun, choose the 7th item in the list and notice how this affects the stroke on your path and that the nodes on the graph correspond to the preset. You can save your own presets using the 5th button from the left which displays the 'Add to Presets' tool tip The next button allows you to edit the list of presets. The last item in this row of buttons is the same Width/Transparency meter found on the ToolBox when the Variable Width button is active for the Freehand tool.

Settings in the Variable Width palette apply to the currently active path as well as to all subsequent paths you create. Therefore, if you don't intent to apply a setting to an active path or subsequent paths, click on the first button on the palette (the Reset button) to clear the settings.

The B-Spline Tool

The B-Spline tool is the next easiest tool to learn and use. To use it, choose the tool (lowercase letter w) which is the third button in the bottom row of the ToolBox and click on the view area to place the first node. Continue clicking to place nodes along the path. To end an open path, double click where you want to end the path or end the path by pressing the Enter key (Return key on a Mac) on your keyboard. To end a closed path, move the cursor to the beginning of the path and click when the cursor changes to add a circular shape next to the regular cursor and click once. The result will be curved segments along the path. If you hold down the Alt key (Option key on the Mac) before clicking to place the next node you can create sharp corner nodes instead of curves. Let's do an exercise and learn about the B-Spline tool.

Exercise 1: Clear your view area or open a new document. Display the grid lines by choosing View > Show > Grid from the menu bar. Grid spacing should be about 1 inch between grids. If you need a bigger grid, choose File > Preferences and choose View and Display from the option box at the top of the Preferences dialog box. Type "1 in" in the Grid Spacing box and close the Preferences dialog box. With the B-Spline tool, make your beginning point by clicking on an intersection on the grid towards the bottom center of your document. Count four intersections to the left, up four intersections, and click again to place your second node. Count up two intersections, two intersections to the right, and click to place your third node. Count two intersections to the right, down two intersections, and this time hold down the Alt (Option) key and click to place your fourth node. Stay with me as we count to the right two intersections, up two intersections, and click to place the fifth node. Once more we will count two intersections to the right, down two intersections, and click to place our sixth node. Finally, hold down the Alt (Option) key and click on top of your beginning point to create a closed path. Now look at your object which should look like this: Figure 4 - The Perfect Heart Shape. Unless you changed a setting, the stroke on your heart is wider than it is on my stroke. The default stroke width is 10 points. Instead of using the Paint Style palette, let's change the width using the stroke width handle. This handle, remember, is next to the arrow at the end of the path. In our case, the end of the path is at the bottom of the heart shape. Choose the Node tool (lower case letter a or lower case letter n), click on the width handle and drag it closer to the arrow on the path. Release the mouse and your stroke should be narrower. Pull on the width handle away from the arrow and the stroke widens. This is a shortcut to the stroke width meter on the Paint Style palette, but not as precise. To get an exact stroke width, use the Paint Style palette.

With the heart shape, we created curves by leaving large spaces between clicks resulting in nice wide curves. With shorter spaces between clicks you create smaller, shorter curves. This makes the B-Spline tool a great tracing tool. Let's do another exercise and learn how to trace images. First, hide the grid since we won't need it for this exercise and delete your heart shape. Next, download the Ed.zip file, upzip the ed.tif image and bring the image into Expression by choosing File > Insert Bitmap from the menu bar. Because the image is a bitmap image, a red grid appears above the image. If the image appears small, click on the image with the Object Select tool and drag the resize handles to enlarge it. The following screen shot is the finished version of Ed. Now, on with the exercise:

Figure 4 - Ed.

I might mention here that you'll find additional information on the B-Spline tool in the Expression 3 user manual beginning on page 165; Tutorial 1: Easy Paths and the B-Spline Tool.

The Strokes Palette

Until now we've used the default stroke for all of our shapes and paths. Other strokes are available when you choose the Skeletal Stroke button on the Paint Style palette and these additional strokes live in the Strokes palette, seen here on the left. Strokes are special files stored in the Expression 3/Strokes sub-directory on your hard drive and some strokes are stored in sub-directories under the Strokes sub-directory. These strokes appear in the stroke list in the Strokes palette. You can switch between sub-directories using the drop down list at the bottom right corner of the Strokes palette. If you have several sub-directories, the drop down box will display a scrollbar which allows you to scroll through the list of sub-directories. The top item in this drop down box lets you display all of the strokes regardless of the directory a stroke is stored in.

Hide Ed's bitmap image for now, leaving only the document you're working on visible, and click on the outline of Ed's face. Assuming that you have a skeletal stroke applied, navigate through the directory drop down list and choose the Dry directory (or folder if you prefer). The list of strokes in the stroke list was replaced with a list of strokes in the Dry folder. From this list of strokes, choose the 'pencil' stroke. Notice how Ed is updated with the new stroke. If you need to, change the stroke width on the Paint Style palette to a larger or smaller size. Next, click on one of the hairs above Ed's ears. Hold down the Shift key and click on the remaining hairs. Holding the Shift key allows you to select more than one object at a time, you remember. If you accidentally select a path you didn't intend to select, click on the path again to deselect it without deselecting the other paths. Choose a stroke and the stoke will attach to each selected path.

I'll save the other items on the Stroke palette for discussion when we learn to create strokes in lesson 4. For now, continue to work on Ed by selecting different paths that make up his face and apply different strokes. When you're ready, read on to learn about the other drawing tools and we'll get back to Ed a little later.

The Polyline Tool

The Polyline tool is similar to the B-Spline tool. With this tool you click to place your first node and continue to click to place subsequent nodes and double click to end an open path. The difference between the tools is that subsequent clicks with the Polyline tool creates sharp corner nodes instead of curves. Below is an example of a simple zig zag path created by clicking on various grid intersections with the Polyline tool:

Figure 5 - Simple zig zag path using the Polyline tool.

With the Polyline tool you can also create curves by clicking and dragging. The curves created with the Polyline tool are very round, as you'll see. This is a little tricky to explain, so bear with me. Suppose that, instead of just clicking at the points on the grid as I did in the above example, I clicked and dragged instead. Doing so would create a scallop instead of a zig zag:

Figure 6 - Simple scalloped path using the Polyline tool.

Let's do another exercise to fully understand the Polyline tool.

Exercise 3: Open a new document and display the grid. Choose the Polyline tool (lowercase w). Click on a grid line intersection to place your first node. Move up two intersections, click again (but don't release the mouse) and drag down to the second intersection to the right of your first click, release the mouse and click on that intersection. To make this a little more clear, consider the following diagram: Where my scallop begins is where I clicked to place my first node. The tiny circle at the intersection two grid intersections up and one intersection to the right is where I clicked and dragged down to the intersection where you see the Polyline cursor. Where you see the cursor is where I released the mouse and clicked to place the node. Continue this click-dragging-click until you get to the point where you want to end the path and then double click to end it. You can combine sharp corners and curves in the same path. Let's make a sailboat. Clear off your view area (don't delete Ed!!) and click on a grid line with the Polyline tool to place the first node. Count 3 intersections to the left and click to place the second node. Count up 5 intersections and click to place the third node. Next, click anywhere to the right of the last node you place and click-drag down to the first node you placed and, when your cursor changes to indicate that you are over the first node, click to end the path. (Remember, double clicking ends an open path and clicking once over the beginning of a path ends a closed path). You should have something like this: Notice that it didn't matter where you click-dragged to create the curve. The Polyline tool will always create a circular curve. Try another sail and click-drag further away than you did the first time and you'll see that the results are the same. Add a simple bottom to the sail boat by simply clicking to create corner points. Notice that a node is not created at the point where you click-drag. Nodes are placed only where you click and release the mouse. Clicking and dragging tells Expression to create a circular curve between the last node you created and the next one you are about to place. Let's make water for our sailboat. Below is a diagram so you can see the intersections I'm referring to in the following explanation: Click on a grid intersection to place the first node. Click-drag (upward) anywhere to the right and click on the intersection two intersections up from the first node. A node will be placed at this intersection. Click-drag to the right again (dragging down this time) and click on the intersection two intersections to the right of your first node. Continue doing this until you want to end the path and double click to end it. When you're finished, notice how nodes are not placed where you clicked and dragged to create the curve, but that nodes do appear in the center of each curve. Click on any node on the path with the Node tool and notice that tangent handles appear on each node that effects that curve, as shown below: First, the tangent handles tell us that these curves are Bezier curves which can be adjusted by moving the node itself, or by adjusting the tangent handles attached to the node. These are not B-Spline curves like those made with the B-Spline tool. Click the Fill button on the Paint Style palette and notice that your waves fill with color from the first beginning node on the path to the ending node. Choose a blue color for the fill. Then select any other sailboat parts and fill those with color as well. Get creative! Experiment with gradients.

If the Polyline tool is a tool you will use often, by all means experiment with it until you fully understand how it works. Let's move on to the Pen tool which has some similarities to the Polyline tool.

The Pen Tool

Fasten your seat belt. The Pen tool, in my opinion, is the most difficult tool to learn. The Pen tool is located below the Freehand tool in the ToolBox (lowercase letter p on your keyboard). Like the Polyline tool, you can click to place the first node and continue to click to create corner nodes. If you use the Pen tool and click to make the zig zag path we made earlier with the Polyline tool, the results would be the same. Double clicking ends the path. Moving to the beginning of the first node on a path will cause the cursor to change, indicating that one click will end the path to create a closed path. Like all of the other tools, except the Freehand tool, you have the option of choosing Do Not Append or Append using the option buttons on the right end of the ToolBox.

The Pen tool will also create Bezier curves but these curves are not circular and are created differently than those created with the Polyline tool. When you click-drag with the Polyline tool, you are not placing a node, but rather, you're telling Expression to create a curve between the last node you created and the next node you place. When you click-drag with the Pen tool, you are actually placing a node and pulling out tangent handles to describe the angle and depth of a curve between curved segments. The entire curve in the curved segment will be influenced by the next node you place. Let's use the Pen tool and try and create the scallop we created earlier with the Polyline tool. If I click on an intersection and then click-drag to the second intersection to the right of the first node, a node is place at the point where I click-dragged, with tangent handles now appearing:

Notice from this screen capture that what is being dragged is a tangent handle. If I click on the intersection where the cursor is, or double click to end the path as I did here, a completely different curve results from the one made with the Polyline tool:

Notice what happens when I adjust the tangent handles for the second node:

Let's create a simple teardrop shape and grasp the concept of tangent handles

Exercise 3: Find space on your document window or open a new document. With the Pen tool click on a grid intersection to place the first node. Click on the second intersection above the first node and click-drag one intersection to the right, like this: Release the mouse and click on the first node to close the path, like this: The tangent handles aren't visible so choose the Node tool (lowercase letter a) and click on the second node (the node at the top of our path) to reveal the handles: Because we click-dragged to place the second node, a curve was created instead of a sharp corner. You can adjust the curve by dragging the second node itself. Test this by clicking on the second node and dragging it down one intersection and release the mouse: Now click on the right tangent handle and drag it to the right one intersection and release the mouse to adjust the curve on the right side of the node: Only the curve on the right side of the node was effected. To change the way tangent handles behave we need to take a look at the Attributes palette. Let's do that now.

The Attributes Palette

A path can have both continuous and discontinuous segments. A continuous segment means that a curve on both sides of a node will be influenced by the tangent handles so that a smooth path will result. A discontinuous segment means a break in the node so that only one side of the curve is influenced, as in our exercise above. We'll use the buttons on the Attributes palette, outlined in red in the image on the left, to create continuous and discontinuous segments.

Clicking the first button will cause both tangent handles to move together so that one tangent handle will always be opposite of the handle being moved. With this button, dragging the right tangent handle down will cause the left tangent handle to move up an equal distance with that of the right handle. This creates a smooth path but the curve on one side of the node will curve in the opposite direction than the curve on the other side of the node. Moving the right handle outward, as we did in the last exercise, will cause the left handle to move to the left an equal distance.

The second button, which displays a "Smooth" tool tip when moused over, will also cause one tangent handle to move an equal distance in the opposite direction when the opposite handle is moved up or down, but only the handle being dragged will move if you drag the handle to the left or right causing only the curve on the side of the node of the handle being moved to be affected. Both the first and second buttons maintain path continuity.

The third button creates discontinuity at a node so that the handle opposite of the handle being dragged is locked. Only the handle being dragged will move so that only the curve on the side of the path being altered with the tangent handle is affected.

The fourth button maintains a relative angle of the tangent handles. Consider the following example where I have adjusted my tangent handles at the top of my teardrop shape as follows:

If I drag the right tangent handle, the opposite handle will move to maintain the angle of the tangent handles, like this:

From the outline showing the results of my dragging motion you can see that the angle of the tangent handles is maintained when the last button (Angle Locked) button is active.

Like I said, the Pen tool is hard to learn and all aspects of this tool would take an entire lesson of it's own to cover. If you feel brave enough to tackle this tool, open another copy of Ed in a new document and try tracing the face with the Pen tool this time. When time allows I will cover this tool in depth in an advanced Expression 3 class.

Adding and Deleting Nodes

There will be times when you will want to edit a path by adding or deleting nodes. The Add Node and Delete Node tools both occupy the 5th space in the bottom row of the ToolBox. The lowercase letter 'm' cycles through these tools. To add a node, choose the Add Node tool and click anywhere along a selected path to place a node there. To delete a node, choose the Delete node tool and click on any node on a selected path to delete that node.

Selecting Multiple Nodes

You can select more than one node for editing at one time and there are three ways to do this. The first way is to select a node with the Node tool and then hold down the Shift key while you click on other nodes. If you accidentally choose a node you didn't intend to select, click on it a second time to deselect it without deselecting other nodes. When more than one node is selected, any editing you do will affect all selected nodes.

Alternatively, if the nodes you want selected are close together, you can drag a marquee around the nodes you want to select with the Node tool. Try this on Ed. Click once on the outline of Ed's face with the Node tool to select the entire face shape. (Clicking once on a path selects the entire path so that the nodes become visible). Then drag a marquee around three of the nodes in Ed's ear, like this:

When you release the mouse you'll see a bounding box around the only three nodes selected, like this:

At his point, if you pull or adjust one node within the bounding box, all of the nodes within the bounding box will be affected. Try this yourself. If you don't like your modification, choose Edit > Undo from the menu bar to reverse the editing.

The third method of selecting multiple nodes is by using the Node Lasso tool, which resides below the Node tool (first tool in the bottom row of the ToolBox). You'll use this tool when you need to select multiple nodes that cannot be selected with a marquee. To do this, select the Node Lasso tool and use it like a pencil to draw around the nodes you want to select. Below is an example of this method of node selecting:

When you release the mouse after drawing, the nodes you captured will be solid red, indicating that these nodes are selected. Again, anything you do to one node will affect all other selected nodes.

Converting Nodes

When you want to convert a curved node into a sharp corner node, and vise versa, use the Node Convert tool which also resides under the Node tool on the ToolBox. Any node can be converted using this tool, but only to convert between curved and corner nodes. You cannot convert a B-Spline curve to a Bezier curve with this tool.

Stacking Order

When you create objects in the view area, each object you create is on top of the last one you created. This is referred to in Expression as the 'stacking order.' Stacking order becomes important when you want to create objects between other objects. Consider Ed, for example. We have created a number of paths on top of the face shape, including Ed's eye, his mouth, eyes, eye brows and several other objects. But what if we want to add a little shading to Ed's face? If we create new objects for shading now, how are we going to place them below all the other objects above Ed's face?

Expression has menu items to move objects up and down in the stacking order. Choose the Arrange menu item and notice the first 4 items listed there; To Front, To Back, Up One and Down One. We're going to finish Ed as I explain the stacking commands so go back to that document now and follow along. Finishing Ed is your homework assignment for this lesson.

First thing we need to do is click on Ed's face to select it. You will remember that the face was the first object we created so it is on the very bottom of the stacking order. Press the Ctrl-D key combination on your keyboard to duplicate the face shape. The duplicate should now be on top of all other paths. We don't want to disturb the other objects under the duplicate so let's lock them. Right click on the view area and choose 'Select All' from the context menu. This selects everything, including the duplicate. Hold down the Shift key and click once on the duplicate to deselect it from the other selected objects. Now choose Arrange > Group from the menu bar. Right click on the view area again and choose 'Lock Object.' Because we deselected the duplicate, everything in the view area is locked except the duplicate that we want to work on.

It is important to explain why we grouped the objects before locking them. You can lock several objects at once by selecting them and choosing the lock operation as we did before, but to unlock them again, you need to choose each item and unlock it individually. This becomes extremely difficult if you don't know the stacking order of the objects, and each object needs to be selected and unlocked in stacking order. By grouping the objects first, you can unlock them all at once.

Select the duplicate and choose the Delete Node tool (lowercase m). Click on each node in the left ear of the duplicate until the ear disappears. Do the same thing with the other ear. You should now have a duplicate of Ed's face minus his ears. Click on the No Stroke button on the Paint Style palette to remove the stroke from the duplicate. Hold the Shift key down as you click and drag on a resize handle on the bounding box to reduce the size of the duplicate to approximately two-thirds it's original size. On the Paint Style palette, choose a skin tone color a shade or two lighter than the color used in Ed's face. (You can paste the color we used earlier and reduce the lightness value in the HSL color picker, or just choose a lighter color.) Click on the Soft Edge/Emboss meter and enter a value of about 40.

You've created a shading object and this object needs to be one object above Ed's face. Move this new shading object out of the way for a moment and then click on the grouped/locked objects, right click on the view area and choose Unlock from the context menu. All of the objects will be selected because they are still grouped togehter. Choose Arrange > Ungroup and then deselect the objects. Move the new shading object over the other objects and position it so it's approximately in the center of Ed's face. From the menu bar, choose Arrange > To Back and then Arrange > Up One. Doing it this way was much easier than continually choosing Arrange > Down One until you reached the proper position in the stacking order, but it could certainly be done this way.

Homework Assignment

Your homework assignment is to complete Ed. You might give Ed's face a second layer of shading (my Ed has three shading layers). If you find that the shading isn't as soft as you'd like, try moving the transparency slider for the fill color to soften it. You'll also need to create Ed's neck and move it to the very back. Maybe you'll want to add shading to the neck as well. Then create the collar on Ed's sweater. You might want to look through the Strokes palette and choose different strokes for the collar. Give the collar a fill color and maybe a texture or pattern. Anything goes here. Above all else, have fun!

Also, make copies of the Ed bitmap image and try tracing with the other drawing tools. Decide which tools work best for you and work with them until you are comfortable using them.

This concludes lesson 3. Next week we will examine how strokes are applied to a path, the difference between skeletal strokes and bitmap strokes, and we will learn to make our own strokes. The fun never ends! See you then.