On previous versions of Inventor a component was grounded by placing a component, going to the ‘Assemble’ Ribbon under the productivity tab and selecting ‘Ground and Root Component’, then choosing the component. This would then cause that component to be grounded and repositioned in the assembly tree.
The new 2018.2 update has revamped this, it is still found in the same location, however, it now opens up a dialogue box which gives you three options as shown below. This format shown in the screenshot is how the ground components is set by default.
The new update allows you to ground more than one component, this can provide a handy feature if the assembly has parts attached to more than one fixed surface. To ground a part by not fixing it to the origin, right click on the part, and select ‘Grounded’. You can ground any component either in free space or a part that has previously been constrained.
When grounding the component at the origin it moves the component and grounds the component to the origin of the assembly.
‘Create origin flush constraints’ when selected adds a flush constraint to the origin of the components, to the origin of the assembly.
Finally, ‘Reposition to the top of the browser’ will send that component to the top of the assembly browser on the left hand side.
A shortcut to grounding a component is to right click when placing the component, then select ‘Place grounded at Origin’ from the menu. At any point you can undo this by right clicking on the grounded component and unticking the ‘Grounded’ Selection.