e speak of ellipse, spiral, or rectangle. Every object has a so-called bounding box, which is the area with borders drawn around it.
The borders touch the left-most, right-most, top-most, and bottom-most points of an object. It includes four corner points and four sides, equally important in transformation. The bounding box allows to easily transform any object. It is usually visible by default, but you may want to turn it off (Shift + Command + B).
Point of Transformation
The bounding box usually includes a central point indicated - it is not necessarily the central point of an object, as it is calculated from the box borders. If you don't see the center, try opening the Attributes panel (Command + F11) and click the Show center icon. By default, this central point of an object is considered a point of transformation, or reference point. This means, that when an object is for example scaled up, the center will remain in place, while all other points change position.
Still, while performing transformation, we can change the transformation point. In this case the new point we choose (in relation to the initial shape of an object) will remain in place. I want to emphasize, that a reference point may be assigned in any part of your document, not just within your object.
A major type of transformation is moving. Although many Illustrator users don't even know about it, move is a transformation. Moving an object means changing its coordinates, so the position is altered - hence, moving is transforming.
This is the most popular way to transform, as we always move objects from one place to another. Moving is usually based on the central point of an object, and the transformation point is not changed. Moving is measured in points, pixels, or other distance units that are set in Preferences (Command + K).
Scaling is altering the size of an object. There are many ways of scaling an object in Illustrator, but all of them change the size of an object. Any transformation point may be assigned while scaling. On two-dimensional graphics there are two axes, so the object may be scaled in two directions.
It is possible to scale it separately (horizontally or vertically) - in this case the shape and proportions of object will be changed. Proportional scaling will constrain the object's shape, transforming simultaneously in two directions. Scaling is measured in percents, starting from 100% as the initial object size.
Rotating is changing the object's angle. Varying from 0 to 360 degrees, we can rotate the object from the initial position on a virtual imaginary circle. Depending on the point of transformation we assign, the diameter of this virtual circle may be altered. If we leave the transformation point on the default center of the object's bounding box, then the object will rotate around itself. There are many ways of rotating an object, entering a needed angle. Rotation is measured in degrees from -360 to 360.
Mirroring, or reflecting, is a more complex way of transformation. It flips the object in any direction, reflecting it from the axis we need. We can simply flip an object vertically or horizontally, or insert any other angle. It also rotates it depending on the axis and transformation point.
This transformation (shown below) results in a mirror reflection of the original object, when we assign the point where mirror stands. Keep in mind, that symmetric object won't change after reflecting. Reflection is measured in degrees.
Another complex transformation type is shearing. It means skewing an object (or, more precisely, it's bounding box) according to one axis, around an assigned point. The slant is varied from horizontal or vertical axis to any angle. Shear may be preformed with many tools and commands. It is measured in extent of slant in degrees and shear angle in degrees.
The last transformation type is free transform - as it follows from its name, this method allows to freely transform the object by several parameters at once. This means that position, size, angle, and slant may be changed simultaneously, combining several 