In this video, we’ll show you ways of organizing the elements in your scene in Maya using hierarchies and groups. In Softimage, you use hierarchies for manipulating and animating multiple objects together. You also use them for propagating materials and properties down from parent to child. With hierarchies in Maya, you can do the same thing, but you are actually parenting nodes instead of objects, as you do in Softimage. Remember that an object in Maya is actually a series of connected nodes, as described in the video “Understanding Maya’s Dependency Graph” on this channel. To create a hierarchy, press Shift and first select the children, as we’ll do with these book parts, then select the parent last, and choose Edit>Parent or press the P key, or click the Parent icon in the General shelf. You can also select the children, then middle-click and drag them onto the desired parent node in the Outliner. You’ll notice that the children are actually under the parent’s Transform node, which controls the hierarchy’s location in space. The parent’s Shape node affects only the parent’s geometry, but not the children’s. To unparent the children, middle-click and drag them out from under the parent node into a “neutral space” in the Outliner, Or select the children you want to unparent and choose Edit>Unparent or press Shift+P, or click the Unparent icon in the General shelf. Selection in hierarchies is a bit different in Maya, as there’s nothing like branch selection in Softimage. For details on selection in hierarchies, see the video “Selecting Objects in Maya” on this channel. When you transform a parent, the children come along for the ride, the same as in Softimage. You can still transform the child on its own, And you can use the Preserve Child Transform option to transform the parent without affecting its children. You can create nested hierarchies for transforming larger sets of objects, But as you can see, we can’t open just the front cover anymore without affecting the whole hierarchy. This is where groups become useful for transforming hierarchies. Groups in Maya are nothing like groups are in Softimage, and are actually more like transform groups, which were created to make Maya users comfortable in Softimage. Groups are like hierarchies except that the parent is an empty Transform node, a bit like a null parent object you would use in Softimage. We’ll “un-nest” this hierarchy that we created and create a group with these nodes instead. Multi-select the objects you want and choose Edit>Group or press Ctrl+G, or click the Group icon in the General shelf, and give the new group a name. To add more objects to a group, you can middle-click and drag them in the Outliner, as you do for a hierarchy. When you create a new group, its pivot is at the scene’s origin by default, but if you choose Modify>Center Pivot, it moves to the volumetric center of the objects in the group. Of course, if you open the Group Options box, you can select Center instead of Origin as the pivot location for the next time you create a group. Now you can see that we can rotate just the front cover again without affecting the rest of the hierarchy. You can nest groups to create more complex structures that are useful for both selection and animation. Notice that the book’s transform values, which were zeroed out, become local to its parent’s transform values. Now we can transform the whole group as a single unit. To ungroup specific nodes, just middle-click and drag them into a neutral area of the Outliner. To ungroup everything, select the group and choose Edit>Ungroup or click the Ungroup icon in the General shelf. This deletes that group and unparents the objects in it. Make sure that you don’t select the group and press the Delete key because that will delete the group and everything in it! In the next video, we’ll look at organizing your Maya scene elements with sets and layers.