Axis

Axis nodes act as null objects by adding a new transformational axis to which other objects may be parented. Even when objects already have their own internal axes, it’s sometimes useful to parent in a separate axis. For example, when an Axis node is parented to other objects in a scene, the node globally controls the scene - rotating the axis rotates all objects in the scene.

Inputs and Controls

Connection Type

Connection Name

Function

Input

axis

An optional Axis node input. This links the position, rotation, scale, and skew of the transformed 3D object(s) to the Axis node, so that the transformation controls on the Axis node override the corresponding controls on the TransformGeo node.

If you’ve worked with other 3D applications, you may know the Axis node as a “null” or “locator” object.

 

look

An optional input where you can connect a Camera, Light, or another Axis that the Axis is automatically rotated to point toward. The Axis automatically rotated to point towards the connected input whenever the look input is moved.

 

Control (UI)

Knob (Scripting)

Default Value

Function

Axis Tab

read from file

read_from_file

disabled

When disabled, the axis is configured using the controls on the Axis tab. Enable read from file if you want to read in axis information from an .fbx file using the File tab.

Note:  This control is linked to the read from file control on the File tab.

display

display

wireframe

Adjust the display characteristics of the 3D object. These settings don’t affect the render output of the scene; these are for display purposes only in the 3D Viewer.

off - hides the 3D geometry object.

wireframe - displays only the outlines of the object’s geometry.

solid - displays all geometry with a solid color.

solid + lines - displays the geometry as solid color with the object’s geometry outlines.

textured - displays only the surface texture.

textured + lines - displays the wireframe plus the surface texture.

Note:  The Viewer node 3D > display setting overrides this control.

selectable

selectable

enabled

When enabled, you can make selections as normal in the Viewer. When disabled, points cannot be selected or changed.

file_menu

N/A

Select to import or export a channel file:

Import chan file - import a channel file and transform the objects attached to the Axis node according to the transformation data in the channel file. Channel files contain a set of Cartesian coordinates for every frame of animation in a given shot. You can create and export them using Nuke or 3D tracking software, such as 3D-Equalizer, Maya, or Boujou.

Export chan file - export the translation parameters that you’ve applied to the Axis node as a channel file. This is a useful method of sharing setups between artists.

snap_menu

N/A

Match selection position - the objects attached to the Axis are snapped to a new position depending on the points selected.

Match selection position, orientation - the objects attached to the Axis are snapped to a new position and orientation depending on the points selected.

Match selection position, orientation, size - the objects attached to the Axis are snapped to a new position, orientation, and size depending on the points selected.

transform order

xform_order

SRT

Sets the operation order for scale (S), rotation (R), and translation (T). The possible operation combinations are SRT, STR, RST, RTS, TSR, TRS.

rotation order

rot_order

ZXY

Sets the order of rotation. The possible axial combinations are ZXY, XYZ, XZY, YXZ, YZX, ZXY, ZYX.

translate

translate

0, 0, 0

Lets you translate the 3D objects attached to the Axis node along the x, y, and z axes. You can also adjust translate values by clicking and dragging the axis in the 3D Viewer.

rotate

rotate

0, 0, 0

Lets you rotate the 3D objects attached to the Axis node around the x, y, and z axes. You can adjust rotate values by holding down Ctrl/Cmd and dragging in the 3D Viewer.

scale

scaling

1, 1, 1

Lets you scale the 3D objects attached to the Axis node on the x, y, and z axes.

uniform scale

uniform_scale

1

Lets you scale the 3D objects attached to the Axis node simultaneously on the x, y, and z axes.

skew

skew

0, 0, 0

Lets you skew the 3D objects attached to the Axis node on the x, y, and z axes.

pivot

pivot

0, 0, 0

When you make changes to a 3D object’s position, scaling, skewing, and rotation, these occur from the location of the object’s origin point or pivot. The pivot x, y, and z controls allow you to offset the pivot point and move it anywhere you like - you can even move it outside of the object. Subsequent transformations applied will then occur relative to the new pivot point location.

You can also hold down Ctrl/Cmd+Alt and drag the pivot point to a new location in the 3D Viewer.

Local Matrix

specify matrix

useMatrix

N/A

Enable this control to specify matrix values for the object you’re transforming as an alternative to setting transform, scale, skew and pivot values above.

matrix

matrix

N/A

The matrix displays values from the object’s transform, rotate, scale, skew, and pivot controls.

Check specify matrix and copy or drag-and-drop matrix values from another object to apply those values, for example, if you wanted to align objects in a scene.

World Matrix

World matrix

world_matrix

N/A

Displays the world or absolute xyz transform of the node in world coordinates.

Note:  Unlike the Local matrix, you can’t adjust the World matrix manually.

File Tab

read from file

read_from_file

disabled

When disabled, the axis is configured using the controls on the Axis tab. Enable read from file if you want to read in axis information from an .fbx file.

Note:  This control is linked to the read from file control on the Axis tab.

file

file

N/A

Sets the file path for the .fbx file from which you intend to import axis information.

reload

reload

N/A

Click to reload the axis information from the specified file.

USD Options

scene_graph

N/A

When the file path is pointing to a valid .usd file, the USD Options are displayed.

The USD Options show a scenegraph containing a list of the item names and their paths inside the .usd file.

Click an item to select it and load it into the scene. The selected item can be identified in the Load column.

Items in the .usd file that weren't originally loaded can still be viewed in scenegraph and loaded into the scene.

Note:  For more information about importing Axes from a .usd file, see Importing USD Items.

animation stack name

fbx_take_name

N/A

When the file control is pointing to a valid .fbx file, select the required take name from the dropdown menu.

node name

fbx_node_name

N/A

When the file control is pointing to a valid .fbx file, select the required node name from the dropdown menu.

frame rate

frame_rate

24

When use frame rate is enabled, enter the required frame rate to use instead of the rate specified in the input file.

use frame rate

use_frame_rate

disabled

When enabled, the frame rate from the input file is ignored and the specified frame rate is used instead.

Look Tab

look axis

look_axis

-Z

The axis around which the Axis is rotated to face the look input.

rotate X

look_rotate_x

enabled

Determines whether the rotation occurs around the X axis. Note that for the rotation to truly "look at" the look input, all three of these options must be activated.

rotate Y

look_rotate_y

enabled

Determines whether the rotation occurs around the Y axis. Note that for the rotation to truly "look at" the look input, you have to set all three of these options.

rotate Z

look_rotate_z

enabled

Determines whether the rotation occurs around the Z axis. Note that for the rotation to truly "look at" the look input, you have to set all three of these options.

look strength

look_strength

1

Determines to what extent the Axis rotates to the new orientation. The smaller the value, the less the object is rotated. Setting the value to 0 produces no rotation.

use quaternions

look_use_quaternions

disabled

Uses an alternate scheme to calculate the look rotation. This option may be useful to smooth out erratic rotations along the look axis.

Step-by-Step Guides

Parenting to Axis Objects