Week 3 Class Practical: Part 2 - Grouping

In a similar way to how creating a Boolean operation between 2 objects will automatically group those objects together, you can also manually group objects together in order to make it easier to refer back to them or make changes to them all at once. For example, when making one of my spaceship models for my animation I can group large sets of objects together that I would never want to separate, such as the wings or the engine plus it's details. This grouping operation is simply performed by grouping all of the objects together you would want to group and then going to "Edit" and "Group", or by pressing the hotkey of CTRL+G. To take this grouping a step even further, grouped objects can be grouped together with other grouped objects to created nested groups. Along with naming objects this makes it easier to keep objects together and easier to find. 

If you want to select and manipulate an entire group of objects this has to be done from the outliner window. In the picture below I have made a small group of shapes called "TestGroup". Once in the outliner window you can select the option "Display Handle" from the attribute window under the "Display" section. This will show you the handle for the manipulation tools on this group of objects once selected from the outliner window so you can manipulate them like any normal object.

While testing these different options from the tutorial I did run into a small snag. If you don't change the "World Space" position of this group it will default to 0,0,0. This means that the handle and pivot points also default to 0,0,0 for this object. I found that after making this group of objects I had to go into the attribute editor and manually change the pivot points coordinates in the world space using the window shown in the screenshot below. This is something I need to be mindful of going forward as it could waste a lot of time trying to line everything up correctly using groups. In the next practical session I will ask my tutor about this to see if there is an easier way to set the pivot position, perhaps on the creation of the group.

Next we had a small exercise to help with grouping in which I had to create a set of 4 geometrical shapes, a cube, sphere, cylinder and cone). First I had to group the cube and cylinder together, into a group called "CUBE_CYLINDER" and then the sphere and cone into group "SPHERE_CONE". After this, I had to group the 2 groups together into a group called "ALL_SHAPES".

The next part of this exercise was to ungroup the newly formed "ALL_SHAPES" group and see how the shape groups were broken down. Breaking down the nested group returned the shapes to their previous separate groups. Finally, I had to create the "ALL_SHAPES" group once again. When creating this group for the second time, I still had to rename the group from it's default. This leads me to believe that Maya doesn't keep any history of the names of groups you have previously set up so I should be careful when grouping and ungrouping objects in my projects.