Transforming an Object by Using Blender’s the 3D Manipulator
In Blender’s default configuration, the 3D manipulator is activated and viewable at the center of your selected object. You can use the manipulator to transform any object in a 3D scene. When Blender first starts, the manipulator is in Translate (Grab) mode, which you can determine in two ways:
The manipulator itself looks like a set of colored axes located at the center of the selected object.
In the 3D View’s header, the button with the blue arrow icon on it is depressed to indicate that the manipulator is in Translate mode. By default, the manipulator is oriented to align with the Global axis.
In all transform orientations under Blender, red represents the X-axis, green the Y, and blue the Z. If you think about the primary colors for light, a handy way to think of this is XYZ = RGB.
Switching manipulator modes
As you might expect, translation isn’t the only transform operation available to you with the manipulator. If you refer to the 3D View’s header to the left of where the Transform Orientation menu is located, the button with the blue arc icon on it activates Rotation manipulator mode, and the button with the icon of a line connecting to the corner of a square activates Scale mode.
Press the Rotation mode button to see the change in the look of the 3D manipulator. In this mode, the manipulator is a set of semicircles around the object’s center, with the proper color representing each axis. Left-clicking the Scale mode button for the manipulator changes it to look much like it does in Translate mode, except that you see a small cube, rather than an arrow, at the end of each axis.
The 3D manipulator should be familiar to you if you’ve used other programs, where the corresponding tool might be called a widget or a gizmo. However, the Blender manipulator also does something else: It lets you activate multiple modes at the same time as a combo manipulator. Hold down Shift while pressing the appropriate button to activate a manipulator. You can then make any combination of transform modes active simultaneously.
Many Blender users find this capability particularly helpful for animation, where some situations require quick access to translation and rotation but not necessarily to adjust the object’s scale. The figure shows the three separate modes of the manipulator, as well as the combo manipulator.
Using the manipulator
To translate a selected object with the manipulator, follow these steps:
Make sure that Translate mode is active by left-clicking the Translate manipulator mode button in the 3D View’s header.
Left-click the manipulator arrow that points in the direction you want to move the object and drag to the location where you want to place your object.
For example, to move an object along the X-axis, left-click the red arrow on the manipulator. To cancel the operation, right-click or press Esc.
Notice also the white circle around the origin of the Translate manipulator. To translate a selected object in the X- and Y-axis of the View orientation, left-click and drag this circle. This convenient shortcut prevents you from having to continually switch orientation modes for the manipulator.
You can use the Ctrl and Shift while transforming to have more control. Move in fixed increments with default settings by holding down Ctrl. Hold down Shift while transforming an object to make adjustments on a finer scale. Hold down the Ctrl+Shift key combo while transforming to make adjustments in smaller fixed increments. Interestingly, these same modifier keys work when using any of Blender’s value input fields.
This fixed-increment control is similar to (though not exactly the same as) the basic snapping to the grid, or increment snapping, found in other 2D and 3D applications. Blender also offers the ability to snap your selected object to other objects (or parts of them), called snap targets, in your scene.
Choices for snap targets are Increment, Vertex, Edge, Face, and Volume. Unfortunately, grid snapping is not currently implemented in Blender, so that may be somewhat disorienting if you’re migrating from another application. You choose which snap target you want to use by left-clicking the Snap Element menu in the 3D View’s header, as shown here.
Holding Ctrl while transforming is actually a way to temporarily enable snapping behavior based on a chosen snap target. However, you may prefer snapping to be the default behavior (so you don’t have to hold down Ctrl). You can enable snapping by left-clicking the magnet icon next to the Snap Element menu in the 3D View’s header or by using the Shift+Tab hotkey. This option tells Blender to snap as default and that holding down Ctrl then temporarily disables snapping.
Here are the different available types of snap targets in Blender:
Increment: In Blender’s default behavior, your selection is snapped to fixed increments of Blender’s base unit.
Vertex: The vertex is the fundamental element of a mesh object in Blender. Using this target, the center of your selection snaps to vertices or points (for curves and armatures) in other objects.
Edge: The line connecting vertices is referred to as an edge. Select this target to snap your selection to edges in objects of your scene.
Face: Edges connect to one another to create polygons, referred to as faces. Choose this option to snap to them with your selection.
Volume: When faces connect to create a surface, that closed surface is referred to as a volume. You can choose this option to snap your selection to an object’s volume. This option is particularly useful when creating a rig for animating characters.
Snapping targets work in both Object mode as well as Edit mode.
You can quickly change snap modes by using the Shift+Ctrl+Tab hotkey combination. If you use this hotkey with pie menus enabled, you also have the option of enabling and disabling snapping directly from the menu.
You can observe the changes made to your object in real time by looking in the 3D View’s header (remember, it’s at the bottom of the 3D View by default) as you transform it. The figure shows how the header explicitly indicates how much you’re changing the object in each axis.
Suppose that you don’t want to move the object in the direction of just one axis. Instead, you prefer the freedom to move the object in the plane created by two axes, such as the XY, XZ, or YZ planes. Just Shift+left-click on the axis that’s perpendicular to the plane in which you want to move. This axis is
the one that’s normal to the plane. For example, assuming that you want to scale the object in the XY plane, Shift+left-click the Z-axis cube of the Scale manipulator.
Transform operations are consistent across all manipulator modes in Blender, so you can apply any of these methods of interacting with the Translate manipulator in the Rotate and Scale manipulator modes. The only exception is that Shift+left-clicking an axis on the Rotate manipulator operates just like simply left-clicking the axis: It doesn’t make sense to try to simultaneously rotate around two axes with any form of control. And don’t forget that you aren’t limited to working in just the Global coordinate system. You can choose any of the other four orientations from the Transform Orientation menu and the 3D manipulator adjusts to fit that orientation.