First, let’s briefly introduce the concepts of the pen tool and paths.
The pen tool is a vector drawing tool. Its advantage is that it can draw smooth curves and maintain a smooth effect after scaling or deformation. The vector graphic drawn by the pen tool is called a path. The path is a vector path and is allowed to be unclosed and open. If the starting point and end point are drawn coincidently, a closed path can be obtained. Now let's draw a simple path as shown below. Select the pen tool on the toolbar (shortcut key P)
And keep the options of the Pen tool as shown (above the toolbar): select the second drawing method (simple path) and cancel the rubber band function
Then click on the screen with a pen, and you will see that there are line segments connecting the hit points. Keeping the Shift key pressed can keep the drawn point at an integer multiple of 45 degrees from the previous point (such as zero degrees, 90 degrees )
This can draw horizontal or vertical line segments (the Shift key is pressed starting from the 5th point in the picture)
From the above simple exercise we draw two rules:
- We did not draw the line segments directly, but defined the positions of each point, and the software connected the points to form the lines.
- What controls the shape (direction, distance) of a line segment is not the line segment itself, but the position of each point in the line segment.
Two terms to remember:
- Those points are called anchor points
- Line segments between anchor points are called segments
The anchor points we just drew are also called linear anchor points because the line segments between them are straight lines.
Now let's draw the curved anchor point
We see that when the second and subsequent anchor points are drawn and the direction line is dragged, the shape of the curve also changes.
How are curves generated, and how do we control the shape of the curves? In addition to having the direction and distance of a straight line, the curve has an additional form of curvature. The direction and distance can be achieved by simply changing the position of the anchor point, but how to control the curvature?
As shown in the figure, select the "Direct Selection Tool" on the toolbar and pay attention to the hollow arrow below.
Assume that the four anchor points we just drew are ABCD
Use the "Direct Selection Tool" to select the segment between AB and you will see the direction line we defined when we drew the AB anchor point just now.
Take a closer look at these two directional lines and imagine this:
A person wants to go from point A to point B. When starting from point A, other people at point A will see that he is walking in the upper and right direction, while the person at point B will see that he is walking in the downward direction. The direction to the right is based on the observation results from the two places. You can figure out the route this person is walking: it must be an upper arc similar to a pot lid. Now we select the "Conversion Point Tool" as shown in the picture. This tool is used to modify the direction line.
Then change the direction line on the AB anchor point as shown in the figure below. You will see the change in the curvature of the curve. Note that there is a small dot at the end of the direction line. This dot is called the "handle". You have to click on the handle position to change it. direction line
Combined with the metaphor just made, it is not difficult to understand:
- Modifying the B anchor point direction line to down is equivalent to specifying that person to start from above point A and enter from below point B, then the distance traveled will be an S shape.
- Then modify the direction line of A anchor point to downward, which is equivalent to starting from below point A, and then entering from below point B. The path taken is a downward arc.
The modified direction line is as shown below:
After understanding the impact of the direction of the direction line on the shape of the curve, let's take a look at the impact of the length of the direction line. As shown below, drag the direction line in the same direction: (You can use the "Direct Selection Tool")
For an anchor point, if the direction line is longer, the longer the curve will take in this direction, and vice versa <BR>You can imagine that the curve is a rubber band with two ends at the head and tail. In whichever direction the force is greater, the rubber band will move closer in that direction. On the contrary
In addition to modifying the anchor point, you can also use the "Direct Selection Tool" to modify the shape of the curve on the clip as shown below:
Note: This cannot be said to be "modified the fragment", but should be said to be "modified two anchor points at the same time"
Remember the principle:
fragments are composed of anchor points. Only by modifying the anchor points can the fragment shape be changed. This is an irreversible causal relationship <BR> Let’s summarize:
For the two anchor points BC on this curve except the starting point and the end point, there are two direction lines:
One is the "coming" direction line from the previous anchor point; the other is the "going" direction line leading to the next anchor point. For the starting point, there is only the "going" direction line; for the end point, there is only the "coming" direction line. Let us do a small exercise below the direction line "towards", as shown in the figure:
Now you are asked to draw a curve between the two red points that closely follows the outline of the mouse. It is likely that what you draw will look like the picture below.
Although the requirements are met, 4 anchor points are used on such a path. Look at the picture below:
The same curve effect, here only two anchor points are used to draw and move the positions of the two red dots before drawing. It is very likely that the effect you draw is like this
In fact, you only need to use two anchor points to draw this curve, as shown below
To draw another line in another position, only two anchor points are needed, as shown below:
Remember one principle: the fewer the number of anchor points for drawing a curve, the better. If the number of anchor points increases, it will not only increase the number of drawing steps, but it will also be unfavorable for later modifications. At this point, you will definitely have two problems:
- Two anchor points seem to be able to cover all curve shapes?
This view is obviously wrong. For example, the curve we drew in the first example requires more than two anchor points. - So, how to minimize the number of anchor points used?
In fact, there is another question hidden here: Where is the best anchor point?
Here are the rules I personally summarized:
The curve shape between two anchor points is divided into two categories: C-shaped and S-shaped
Several forms of C shape are as follows:
Their direction lines are as follows:
Several forms of S-shaped curves are as follows:
The S-shaped direction line is as shown below:
The animation below demonstrates the dividing point between a C shape and an S shape when adjusting the direction line.
After understanding (and understanding) the shapes of the two curves C and S, you can analyze how many anchor points are needed before drawing. In fact, it means analyzing how many can be drawn with one curve (C-shaped or S-shaped). Although the number of anchor points in the drawing area can reflect the level and proficiency of the drawer, for most people, as long as it can meet the needs, it is enough. Therefore, when actually drawing, there is no need to be too demanding in reducing the number of anchor points.
Now let's actually draw an M shape, similar to the McDonald's logo. We will introduce three processes. Please read the text description clearly first and then watch the animation demonstration. The first method: After completing the drawing, modify the "direction" of the second anchor point. direction line, and the anchor point position can be moved appropriately (after drawing, hold down the Ctrl key and click anywhere outside the path to complete the drawing)
Among them we noticed a phenomenon:
When you create a new curve anchor point and drag its direction line, what actually moves with the mouse is the "going direction" direction line, while the "coming direction" direction is always at a 180-degree horizontal angle with it, and The length is also the same. Therefore, although we should originally set the "going direction" of the second anchor point to the upper right, in order to get the "coming direction" correct, we have to set it to the lower right first, and then modify it separately after completing the drawing. Its "destination"
This method can be described as "throwing it away to keep it coming" (in the same way, it can also be "throwing it around to keep it coming")
It is very inconvenient when drawing a large number of anchor points because the correct curve cannot always be seen.
Now we introduce the second drawing process:
After establishing the second anchor point and defining the direction line following the "coming direction", modify the "going direction" direction line so that the curve can be drawn correctly (after drawing, hold down the Ctrl key and click anywhere outside the path, to complete the drawing)
