The work area (user interface) > Selection tools > Select 3D objects
  
Select 3D objects
1. Click Modeling and then, in the Utilities group, click Select. The Select dialog box opens.
2. Click 3D Obj. The different 3D objects that you can select are listed in the 3D Objects section of the Select tool. Use this area to select the 3D objects for the task in hand. For example, when using Delete 3D,
a. Open the Select tool.
b. Click WPs in the 3D Objects section to select all workplanes in the viewport.
c. Clear WPs to return to the general selection mode (all 3D objects). You can now select other types of 3D objects in the 3D Object section of the Select dialog box.
To select all...
Click...
Workplanes
WPs
Workplane Sets
WP Sets
Parts
Parts
Assemblies
Assemblies
Containers
Containers
Views
Views
View Sets
View Sets
Docu Planes
Docuplanes
Docu Plane Sets
DP Sets
Matchlines (Lofting)
Matchlines
Coordinate Systems
Coord Sys
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If you click Assemblies under 3D Object, you can select assemblies or containers (sub-type of assembly) in the object tree or viewport.
If you click Containers under 3D Object, you can select only containers (sub-type of assembly) but not assemblies in the object tree or viewport.
Specify the Scope
Solid Part: Allows you to select solid parts.
Face Part: Allows you to select face parts.
Wire Part: Allows you to select wire parts.
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By default, Solid Part, Face Part, and Wire Part are selected.
During an operation in the viewport, if a dialog box does not allow you to select face parts or wire parts, Face Part or Wire Part are respectively disabled.
Choose a selection method for 3D objects
You can choose the level in the assembly structure to which your selection applies by toggling the Recursive check box as follows:
Recursive: Selects all objects that belong to the selected part or assembly and to any of its children (all objects that are at the same or lower level in the Structure Browser).
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Clear Recursive to select only those objects that belong to the selected part or assembly (all objects that are at the same level in the Structure Browser).
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You cannot use the recursive option to select matchlines or views.
You can use any of the following methods to select 3D objects listed in the 3D Objects (Methods) section of the Select tool:
All at Top: Selects all specified 3D objects in the top level (/) of the assembly structure or workplane structure. It does not select anything below the top level unless you switch on the Recursive option.
Active: Selects the active part (Active Part) or workplane (Active WP).
Render Mat: Selects all objects with a specified rendering material.
In WP Set: Selects all specified objects that are in the workplane set you specify. Valid objects are workplanes and matchlines.
In Part: Selects all specified view sets belonging to the part you specify.
In View Set: Selects all specified views belonging to the view set you specify.
In Assembly: Selects all specified objects belonging to the assembly you specify. For example; parts, subassemblies, containers, and view sets are some of the valid objects that you can select.
In DP Set - Selects all docuplanes in a specified docuplane set.
In Feature: Selects all parts or assemblies belonging to a feature. This is intended for use in selecting parts and assemblies belonging to members of part groups. Without Recursive switched on, this option selects all parts and assemblies at the part group's top level. With Recursive switched on, it selects all parts recursively (that is, all parts belonging to all assemblies) within the part group.
By VP Frame: Selects all elements contained within the projection of the frame drawn in the normal direction of the viewport.
By 3D Box: Selects all elements contained within a specified 3D box.
If you select a subassembly within an assembly and there are several different levels, Creo Elements/Direct Modeling will prompt you to confirm which assembly to select. You can trace your way through the assembly structure to select the required assembly.