About External Simplified Representations
Use external simplified representations to store simplified representations of assemblies without having to modify the original assembly. External simplified representations are stored as new models of a special assembly type. You can create multiple external simplified representations to correspond to different assembly areas and levels of detail. Low-level components without top-level and intermediate-level assemblies can be included, so multiple users can work simultaneously. The use of external simplified representations minimizes the risk of accidental modifications to top-level assemblies.
All the components in an external simplified representation are the same as those in the reference assembly. Therefore, it is not necessary to propagate modifications made to the external simplified representation or reference assembly. All modifications to external simplified representations are automatically reflected in the reference assembly.
Rules for External Simplified Representations
External simplified representations are stored in a separate assembly (.asm) file with an external simplified representation subtype.
The creation, redefinition, or removal of an external simplified representation does not change the reference assembly.
The reference assembly need not be in session when working with external simplified representations.
Components from any level of the reference assembly can be included in the external simplified representation. The reference assembly and intermediate subassemblies can be excluded even if low-level components are included.
When a model contains substituted components, the top level assembly is always included in the external simplified representation.
The location of components included in external simplified representations is fully associated with corresponding components of the reference assembly.
You can specify whether components included in external simplified representations can be modified or used for reference purposes only.
References can be created within external simplified representations. These references are treated as if they were created in the reference assembly.
Component and feature operations can be performed on the top level of an external simplified representation model.
When you create the external simplified representation from a representation of a design assembly with a flexible component, the flexible component cannot be included when all assemblies on the path to this component, including the top-level assembly are excluded. To include this component, you need to include the design assembly or the direct owner assembly.
Creating External Simplified Representations
 Use the following methods to create external simplified representations:
View Manager—Select a simplified representation, then click Edit > Copy As External.
File > New—Select the reference assembly model during the assembly creation process.