You can import meshes (or NURBS curves/patch surfaces converted to meshes) and point clouds from Alembic files (.abc file format) into a Nuke scene. During the import, Nuke allows you to control which nodes in the Alembic scene get loaded by using an import dialog. If there is only one item in the Alembic file, it loads automatically. Below is an example of an imported octopus Alembic file, courtesy of Sony Pictures Imageworks.
For more information on Alembic, see http://code.google.com/p/alembic/
TIP: In addition to meshes and point clouds, you can also import cameras and transforms from Alembic files.
To learn how to export files in the Alembic (.abc) format, refer to Exporting Geometry, Cameras, Lights, Axes, or Point Clouds for more information.
| 1. | Click Image > Read or press R on the Node Graph. |
The Read File(s) dialog displays.
| 2. | Select the Alembic file you want to import from the file location, then click Open. |
The Alembic import dialog displays. By default, all items are selected in the Scene Graph when the import dialog is opened, as shown below:
Selected parent items are indicated by a yellow circle, and selected child items by a yellow bar (these turn orange when you select them in the list). Unselected items do not have an indicator next to them.
| 3. | To import specific items, you must first deselect the root item by clicking on the yellow circle. This de-selects the root and any child items. Then, select specific items in the scenegraph by clicking on the blank space where the circles had been, as shown below: |
Alternatively, you can right-click on an item and select:
• Select as parent - to select this item and make it a parent to other items. This allows you to create a separate Nuke node for this item (and any child items underneath it) in the next step.
• Select as child - to select this item and make it a child to the nearest parent item up the tree.
• Deselect - to deselect this item (that is, not import it from the scene).
You can also select multiple items by pressing Ctrl/Cmd or Shift while clicking them.
| 4. | Do one of the following: |
• Click Create all-in-one node to create one Nuke node for everything that’s selected, regardless of whether the items are selected as parent or child.
• Click Create parents as separate nodes to create one Nuke node for each parent item (yellow circle) in the tree. This node contains all the child items (yellow bars) under the parent.
Nuke creates ReadGeo, Camera, and Axis nodes as necessary, depending on what you selected to import from the scene.
| 5. | On ReadGeo nodes, you can adjust the following: |
• If the objects you imported are animated, make sure read on each frame is checked. This preserves the animation. When read on each frame is disabled, use lock frame to select the frame the object is loaded at.
• If you don’t want to render motion blur, disable sub frame for faster UI interactions.
• In the frame rate field, define a frame rate (frames per second) to sample the animation curves.
• Use render points as to determine how point primitives are rendered: either as Nuke point clouds or Nuke particles.
• Enable use geometry colors to apply geometry color attributes read from .abc files and apply them to the Nuke geometry.
NOTE: When disabled, this control can cause differences in rendered output when compared to previous versions of Nuke. If this occurs, enable use geometry colors in the ReadGeo properties panel.
• Any mesh items imported are listed on the Scenegraph tab of the ReadGeo node. To display all items that exist in the Alembic file in the list, check view entire scenegraph. This allows you to add items to the list or remove them from it by clicking on the yellow and blank indicators on the right.
TIP: To load specific items from an Alembic file, you can also create a ReadGeo, Camera, or Axis node, check read from file, and click the folder icon on the File tab to browse to an .abc file.