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Home >> Layout & Simulation >> Instances

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Instances are a special item type in MODO that add little additional data overhead to a scene, as Instances contain no actual geometry. They instead references a source object at render time, allowing users to generate a huge number of duplicates for an item with little additional memory usage or performance hit. As an added benefit, users can modify the source geometry at any time and the changes will automatically propagate to each Instance. For example, consider a model of a computer case, where each bolt is an instance of a single mesh. When the client decides the bolt needs to be a hex head rather than a standard phillips head, all instances of the bolt can be easily updated by simply modifying or replacing the geometry in the source item.

Instances are as easy to create as a normal duplicate, and many cloning and array tools offer additional functionality to generate Instances instead of direct geometric clones. Instances themselves can be treated like normal mesh layers, each having its own set of transforms and render options. Users can select them like any other item, and position, scale and rotate them. This allows users a great deal of control over placement of the copies. While Instances reference their shading and material settings from the source object, users can assign an 'Item Mask' through a 'Material Group' item in the shader tree and target custom surface settings to a specific Instance.

Mesh Instances are differentiated in the Items list by their pink cube shader tree icon (as opposed to the standard blue-gray cube icon for Mesh items). Instances are also distinct in that the layer name is displayed italicized and their unselected wireframe representation in the viewport is always by default pink in color. Instances are not limited to mesh items, instances are useful whenever users have a large number of like items. If a series of streetlights in a scene all shared identical settings, users could instance the first light and then later on, just as with mesh items, changes made to the source light will propagate to all the instances.

Instance Sample


Creating Instances

The simplest method of creating an Instance is to simply select a mesh item (while in 'Items' mode of course) and press 'Shift+D' on the keyboard. Users can also RMB+click directly on a item layer in the Items list (while in any mode) and select the 'Instance' (or 'Instance Hierarchy') option from the context menu. A menu bar command is provided as well. Select an item layer in the item list or directly in the 3D viewport and invoke the command "Item > Instance".

When invoked while in 'Items' selection mode, many of the duplication tools, such as 'Clone', 'Curve Clone' and 'Radial Array' provide an option to generate Instances; with the tool active, simply enable the 'Instance' checkbox and the clones will be instances instead of generating full geometry. Alternate versions of the tools are generally available as alternate buttons (alternate buttons are denoted by the small arrow in the bottom right corner, LMB+click and hold to open the popup menu to select the alternate tools)


Selecting Instances

Once an instance has been created, users can work with it like any other item in the scene. Users can select them and transform then directly in the 3D viewport or use the numerical settings found in the Properties panel when the item is selected. While it is possible to select and modify the 'Center' and 'Pivot' position of an Instance, this actually moves the Instance itself. To modify a Center, users would need to edit the source item. However, since Instance placement is based on the items Center, modifying the Center point of the source would move all the instanced items.

If a complex scene makes it difficult to locate the source item of an Instance, users can select the Instance and then invoke the menu bar command "Select > Source of Instance" This command is also available via the RMB context menu within the Items list viewport. RMB+click in the instance and choose the 'Select Source of Instance' option from the popup menu.

Users can convert an Instance to a normal mesh item for further editing, if desired, by using the 'Convert to Mesh' button available in the 'Properties' panel whenever an Instance is selected. Additionally, users can RMB+click on the item layer itself, opening the context menu, and choosing the 'Change Type > Mesh' option. Finally, users may access the same command from the menu bar under "Item > Change Type > Mesh".


Building a Mask for an Instance

To apply surfacing to an Instance that is different from the source mesh, assign an 'Items' mask. This is done by opening the contextual menu by RMB+clicking over the target 'Instance' and selecting the command "Create Item Mask". The resulting Shader Tree material Group can then be populated with any number of Shader Tree layers. The following video demonstrates the workflow-


Tip icon

TIP: The difference between cloning (duplicating) geometry in a component mode versus cloning while in Items mode is that each clone becomes its own Item layer in the Items list. Cloning while in a component mode merely duplicates the geometry within the same existing item layer. If you feel the items list becomes too cluttered with Instances, users can simply LMB+click on the top instance layer, and then pressing and holding down shift and LMB+clicking on the bottom layer to gang select all layers, then pressing 'Ctrl+G' to automatically parent all the selected items to a Group Locator in the Items list. Users can then toggle the visibility of all the child items by LMB+clicking the arrow icon 'arrow' preceding the Group layers name. Likewise, users can also toggle visibility of the Instances themselves by enabling/disabling the eye 'eye' of the parent group (assuming that the Preference to do so isn't disabled).



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