Overview
RIB fragments aim to speed up multi-frame renderings and re-renderings of a frame. This is done by storing into a file a portion (fragment) of the data computed by 3Delight for Maya so it can be re-used for subsequent renderings.
The RIB Fragments group with one RIB Fragment defined.
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When re-rendering multiple times the same frame, a single fragment will suffice. When rendering multiple frames, fragments work best when using distinct fragments for static and animated objects. |
How RIB Fragments work
RIB Fragments are RIB Fragments are used to store in files the geometry data produced right before every rendering. A RIB Fragment file contains the geometry of all objects in the fragment’s associated object set. Once the fragment file RIB Fragment is written, subsequent renderings can simply assume that the objects in the fragment’s set have already been processed and skip several of the steps that occur before the actual image rendering begins.
RIB fragments aim to speed up multiple renderings and multi-frame renderings. When re- rendering multiple times the same frame, a single fragment will suffice. When rendering multiple frames, fragments work best when using distinct fragments for static and animated objects.
The RIB fragment files contain A RIB Fragment contains only geometric information about the objects. All other data, such as light linking, transformations, shading and attributes, are not stored in the fragment file. The RIB archive node Archive Node is better suited when some (or all) of this extra data is needed in the file; see Section 3.11 [ The RIB Archive Node], page 82.
If a scene object is set to be in several fragments, only the fragment closer to the top of the list will actually contain that object. In other words, if several fragments are used and only the last one’s "Object Set" is set to ‘<all visible objects>’, this last fragment will contain only the objects that none of the above fragments contain.Figure 3.58:
Common Attributes
The RIB Fragments
panelgroup
Each fragment is shown in its own panelsubgroup. To add a fragment, either click on the Add RIB Fragment button, or select "'Add RIB Fragment" ' in the contextual popup menu that appears when right-clicking almost everywhere anywhere in the RIB Fragments panel group. This menu also offers options to expand or collapse all display panels at once, and turn on or off all fragment’s "'Use" ' or "'Write" toggles. To remove a display, click on its Remove Display button, which appears as a trashcan. ' toggles.
At the top of the RIB Fragments panel are a few general controls, followed by a list of per- fragment panels. The general controls affect all RIB fragments, and are:
‘Binary Rib’ RIB
When this options is on, the RIB file will be saved in binary format, producing a smaller file. Turn this option off to produce a text RIB file, which is bigger but easier to read and edit. By default, this option is
offon.
‘Compressed Rib’RIB
This option controls if the RIB file will be compressed, producing a smaller file. By default this option is off.
‘ Write Mode’
This attribute controls when a fragment file is written. The available values are:
Chapter 3: The User Interface 73
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| Option | Description |
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| Reuse existing fragments |
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| When this value is selected, |
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| 3Delight For |
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| Maya will look for the fragment file specified in the |
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| fragment’s Filename |
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| attribute. If the file exists, then the fragment file is assumed to be up to date |
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| ; bypassing the need to process all elements of the fragment's Object Set. If the file does not exist, it will be created unless the |
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| fragment’s "Write" |
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| attribute is turned off. |
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| Overwrite_existing_fragments |
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| When this value is selected, the file specified in the |
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| fragment’s "Filename" |
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| attribute will be overwritten every time a rendering is requested, unless the |
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| fragment’s "Write" |
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| attribute is turned off. This is the default. |
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Add RIB Fragment
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Clicking on this button will create a new RIB fragment.
Per Fragment Attributes
Per-RIB Fragment attributes
Use
When this attribute is off, the fragment is completely ignored and the objects in its "Object Set" will be output as usual. This attribute is on by default. Note that it is possible to change all fragments’ "Use" attribute at once using the contextual popup menu’s ‘Use All’ and ‘Use None’ menu options.
‘Write
’Controls if the fragment file can be written. The condition in which a fragment file is written is determined by the
"Write Mode
" (see [RIB fragments write mode], page 72)in the RIB Fragment's common attributes.. This attribute is on by default. Note that it is possible to change all fragments’
"Write
" attributeattribute at once using the contextual popup menu’s
‘Write All’ and ‘Write None’‘Write All’ and ‘Write None’ menu options.
‘
Remove RIB Fragment
This button appears as a small trashcan. Clicking on this button removes the fragment from the render pass.
‘Filename
’The path of the file that will contain this fragment’s objects geometric data. If the path is relative, it is assumed to be relative to the 3Delight RIB Fragments project path (see
Section 5.5.5 [Automatic File Output Control], page 1263Delight Data Locations). When these objects are animated, it is recommended to add the frame number to the filename; see
Section 5.5.4 [], page 124for details.
‘Browse for RIB File button
’This button, drawn as a folder, brings up a file browser to specify a RIB filename.
‘View RIB button
’This button, drawn as a magnifying glass, will open the fragment’s RIB file in a viewing application. See
Section 3.17 [ Window], page 93for details on how to specify which application should be launched.
‘Object Set
’This attribute specifies which objects are contained in the fragment’s file. If an object is set to be in several fragments, only the fragment closest to the top of the fragment list will actually contain the object. The default value is
‘<all‘<all visible
objects>’objects>’, which means the fragment will contain all visible objects that are not already in a fragment above this one.