In a "bottom up" design, large or complex assemblies are broken down into smaller subassemblies and components.  Each component is designed as a separate part by one or more designers.  The component parts can be archived in a library in one or more VX Files.  This is the most efficient way to create and manage large or complex assemblies.

 

Each part is inserted into the active part creating a component instance and thus an assembly.  The component becomes the child of the active part and then it becomes the active part.  Because an instance of the actual part is used, you can have it update automatically if the archived part is modified or you can modify the archived part by activating and modifying its component instance.  VX is very flexible in this regard.

 

 

 

The "bottom up" design hierarchy of the basic assembly example is shown below.  All of the components exist prior to Part1.  When Part1 is created, it becomes the active part.  You would use the following menu/command sequence to insert Bracket and it becomes the active part.

 

InsertComponent

 

Or

Assembly Design Tool Bar

 

 

Basic Assembly of Part1
 

 

Bracket is now a child of Part1.  The dashed line shows that Bracket resides in the VX file Parts.VX.  The dotted line shows that Bracket is inserted (instanced) into Part1.  After Bracket is inserted, Part1 is reactivated. Bolt and Washer are then inserted using the same procedure and Part1 is reactivated again.
 

 

 

Part1 Hierarchy using "Bottom Up" Design

 

 

 

Module Subassembly is inserted like the Bracket, Bolt, and Washer again becoming a child of Part1.  However, because Module Subassembly already contains the two components Seal and Module, they are inserted also and remain its children.
 

To Summarize:
 

• File1 contains 1 part (Part1).

• Part1 contains 4 components (Bracket, Bolt, Washer, and Module Subassembly).

• Module Subassembly contains 2 components (Seal and Module).

• All of the components are instances of the original parts that reside in the VX file Parts.VX.

• If File1 is removed from the active session before it is saved, it and Part1 are deleted.  The original parts located in the file Parts.VX are not affected.

• If File1 is savedPart1 is also saved.

• If File1 is deleted, Part1 is deleted.

 

 

 

In a "top down" design all components are typically designed by the same person within a single part.  VX handles "top down" design by allowing you to create and design a component while you are in the active part.  By doing so, the active part then becomes an assembly.

 

The component becomes a child of the active part and then it becomes the active part.  The component, when created, is an instance of an original part which becomes a root object placed in the active file.  The part or each component is activated and edited as desired.  The "top down" design has its advantages. If you are working on a new design you may elect to keep all component parts in the same file until the design is near completion.  If the project is canceled or if you decide to go in a totally new direction, deleting the file will delete the part and all of its components.

 

 

 

The "top down" design hierarchy of the basic assembly example is shown below.  None of the components exist prior to Part1.  When Part1 is created, it becomes the active part.  You would use the following menu/command sequence to create Bracket and make it the active part.
 

Assembly Design Tool Bar
 

 

Basic Assembly of Part1

 

 

Bracket is a child of Part1. The dashed line shows that by default when Bracket is created, it is added to File1.  The dotted line shows that Bracket is inserted (instanced) into Part1.  When Bracket is complete Part1 is reactivated. Bolt and Washer are then created using the same procedure and Part1 is reactivated again.  

 

Part1 Hierarchy using Top Down Design
 

 

Module Subassembly is created like the Bracket, Bolt, and Washer again becoming a child of Part1.  However, Module Subassembly remains active (i.e., Part1 is not reactivated) when Seal is created.  Seal becomes the active part and by default also resides in File1 but is inserted into Module Subassembly because it was active at the time Seal was created.  Module Subassembly is then reactivated and Module is created similar to Seal.

 

To Summarize:
 

• File1 contains 7 parts (Part1, Bracket, Bolt, Washer, Module Subassembly, Seal, and Module).

• Part1 contains 4 components (Bracket, Bolt, Washer, and Module Subassembly) which are instances of the original parts located in File1.

• Module Subassembly contains 2 components (Seal and Module) which are also instances of the original parts located in File1.

• If File1 is saved it contains all of its original parts.

• If File1 is deleted, it and all of its original parts are deleted.
  
   

 

VX supports variational assemblies using 3D constraints.  When a component is created (as in a "top down" design) or inserted (as in a "bottom up" design) it becomes the active part. 3D constraints are used to position it relative to other components within the assembly.  When a constraint is placed on a component, one or more of its degrees of freedom (DOF) are eliminated.

 

DOF refers to the six directions in which a component is free to move when it is first created or inserted into an assembly.  These directions include three linear and three rotational as shown below.  There are six 3D constraints to choose from (Coincident, Tangent, Concentric, Parallel, Perpendicular and Angular).  Each constrains a point, curve, edge, face or datum plane on the component to that of a parent object.  A wide variety of constraint conditions can be created using these conditions and entity types.  The parent object can be another component or the root part.
 

 

The Six Degrees of Freedom (DOF)