Level of Detail representations improve capacity and performance. They suppress unneeded components or replace many parts with a single part representation to reduce memory consumption and to simplify the modeling environment. Save the representation with a name and activate it for modeling tasks or select it for creating drawings, presentations, and derived assemblies. A derived part created from an assembly that uses an LOD with a reduced number of parts can be used in the same assembly it was created from as a Substitute LOD. A simplified substitute provides greater memory savings than suppression alone. When a Substitute Level of Detail is active, all components are suppressed and hidden in the browser.
Performance improvements occur when an upper level assembly (consuming assembly) uses a lower-level assembly with a Level of Detail representation that contains a reduced number of parts or a Substitute Level of Detail.
Use some of the following techniques in a new Level of Detail representation:
- Suppress components not needed for the current task. You can continue working with loaded components.
- Use in conjunction with Design View and Positional representations to customize the visibility state, position, constraint value overrides, and other attributes.
- Use for managing memory while facilitating iAssembly Configurations to manage design alternatives.
Use some of the following techniques to create a Substitute Level of Detail representation to use a part file in place of the assembly:
- Create a surface composite Shrinkwrap to create the smallest possible substitute part file. A single surface composite feature is the default Shrinkwrap setting.
- Create a derived part from the assembly to use as a substitute Level of Detail.
- Create a new part file that represents a simplified version of the assembly to use as a substitute Level of Detail.
In addition, the status bar shows a capacity meter. This indicates how many total occurrences are in the open document and how many open files are in the total session. A colored gauge indicates how much of the total memory available to Autodesk Inventor is being used.
System-defined Level of Detail representations
You can choose among several Level of Detail representations when you open a new or updated assembly.
In the Open dialog box, click Options to select a system-defined Level of Detail representation: Master, All Components Suppressed , All Parts Suppressed , or All Content Center Suppressed .
It may be useful to open a large assembly with all parts suppressed, for example, and then unsuppress only the parts you need. You can save the custom state as a new Level of Detail representation.
You cannot modify a system-level representation, but you can make modifications and save them to a user-named representation. For example, you can copy All Content Center Suppressed, and then select all internal components. Suppress the selected components, resulting in only the external components loaded in memory. By selecting New in the context menu of the Level of Detail browser, you can create a new user-named Level of Detail representation that captures the current suppression states.
Level of Detail representations in drawings
You can select a Level of Detail representation when creating a drawing view. If the representation has some subassemblies suppressed so that you can work on a hidden subassembly, the drawing view represents that state. A view created from a Substitute Level of Detail reflects the state of the substitute part in the drawing view.
You can also select Design View and Positional representations, so that the combination is represented in the view.
After the view is created, you can edit it to change to a different representation, if appropriate.
Level of Detail representations in presentations
Like drawings and other assemblies, presentations use specified Level of Detail representations. You can use a Substitute Level of Detail to create a presentation but, it consists of a single part.
In the assembly, create a Level of Detail representation and save the file. In a new presentation file, create a view and browse to the appropriate assembly. Use Options to specify the appropriate Level of Detail representation.
Further, a presentation updates to reflect changes in the Level of Detail representation. For example, if you add tweaks in a presentation, and then edit the representation in the assembly to suppress more parts, when you return to the presentation, it represents the new state. If parts were deleted that participated in a tweak, the tweaks are deleted.
If a Level of Detail is deleted from the assembly, the presentation reverts to using the master Level of Detail representation.
Use View and Positional representations with Level of Detail representations
Level of Detail, View, and Positional representations can be used together. Adjusting one type of the representations does not alter the others.
Update mass properties
Mass properties cannot be updated when there are unsaved changes in a non-master Level of Detail representation.
When you suppress or unsuppress a component in a Level of Detail representation, and try to update, a message warns you that some components are out of date and provides a way to save them. When all components are saved, you can update.
When you want to calculate mass properties, and the assembly has suppressed components, you are prompted if you want to calculate mass properties for all components. If yes, the suppressed components are temporarily loaded to calculate mass properties. If no, the mass properties are calculated on the currently loaded components, which means zero mass for suppressed components.
Right-click at the top-level assembly and select iProperties. Click the Physical tab to verify that mass properties are updated.
Work with the bill of materials
The Assembly bill of materials uses the master Level of Detail representation to show the complete model in its views. The following operations are affected:
- BOM Editor: If you edit the active Level of Detail representation, the Editor prompts you to save the active representation changes so it can access the updated master Level of Detail.
- Assembly bill of materials response to editing a nonmaster Level of Detail representation: Usually, the Assembly bill of materials updates when you add or remove an instance. If the active Level of Detail representation is not the master, Assembly bill of materials updates are deferred until you next access the bill of materials.
- Parts lists and balloons: Changes to the bill of materials are reflected in parts lists and balloons. When you suppress a component in a Level of Detail representation, the drawing view updates and attached balloons are deleted. The parts list does not change because it always refers to the master representation.
Publish DWF data
The published file represents the active Level of Detail representation including a Substitute Level of Detail. Activate the appropriate representation in the browser and then use 
Publish or Save Copy As. Specify the DWF file type and desired options. All components regardless of their suppression state are present in the published DWF model browser.
Solving constraints
Some constraints may be affected by component suppression. For example, transitional constraints cannot be solved if a component is suppressed, but rotational and other types of constraints are not affected.
Suppressed components are not adaptive.
Temporary Level of Detail representation
At times, a subassembly is set to a temporary Level of Detail. This happens when a parent assembly adjusts a suppression status within the subassembly, thereby making the Level of Detail invalid. The subassembly is not modified, however. A tilde and index at the end of the subassembly name indicate that the subassembly is in a temporary Level of Detail state.
If you open the subassembly in its own window, the suppression states are retained and a new Level of Detail representation is created so you can save the suppression states with the assembly.