NX Large Assembly Best Practices Final 1


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Large Assembly Best Practices


Large Assembly Design Challenge

Designing systems, assemblies, and parts to meet the

requirements of complex products,

in the face of …

large data sets:

The term "large" assembly is a

relative one. Large assemblies for some may be

1,000 parts while for others 10,000 or 100,000+…

complex geometry:

Nurb surface data

constantly-changing data

large, distributed teams designing

in same assembly space


Large assembly handling in NX

(1) Load Performance and Capacity: Reduce the amount of data per component loaded

(2) Simplification of assembly data : Reduce the complexity of components loaded

(3) Context control: Reduce the number of components loaded

(4) Visualization settings and Memory utilization: Utilize memory more efficiently.

NX contains leading-edge tools and techniques to facilitate working on large assemblies

NX has a long and successful history of providing solutions for such industries as aerospace,

automotive, heavy machinery, shipbuilding, etc. where large assembly requirements are a key element


Load Performance and Capacity

Load Options

What are they?

 A set of options that allow you to control how much and in what form component data is loaded

Important Properties

 Lots of settings including:

 Load Method - the location of the data

 Load Components – all components, no components

or use component filters

 Partial Loading – display data only

 Determine action that should taken if a component cannot be loaded

 Save and restore specific configurations

 Accessible from the Open dialog box


 Using Load Options effectively is one of the most important ways to improving large assembly performance


Only load the components that you need to see to do your job

Load Options: Selective Loading



Faster load times

Less memory used


Load with “no components”

Open components using:

Assembly Navigator

Component filtering



Load Options : Lightweight Creation

Faceting tolerance

Faceting tolerance affects

smoothness, performance,

& memory usage

Default value: calculated per body,

based on bounding box size

User-specified value:

Per body:



Per session: Assemblies



Load Performance and Capacity

Reference sets

What are they?

 Named sections or partitions of a NX part created in the Assemblies application

 Lets you control the amount of data that is loaded from each component and viewed in the context of an assembly

Important Properties

 Two types:

 Automatic - managed by the system (Empty, Entire part, Model and Simplified)

 User defined - created and modified for your own purposes (Ex: Mate, Simple, Draft)


 A well-managed reference set strategy can lead to:

 Faster load times

 Reduced memory usage


Occasional Piece Part Ref Sets


MODEL ref set plus mating geometry


Simplified geometry

Entire Part



Avoiding & Coping With Assy-Level Ref Sets

1. Use layers to hide unwanted geometry

2. Use assembly-level reference sets with

Add New Components Automatically switch (NX 3)

Possible Exceptions and Alternative Approaches

Customer Default

Create Ref Set Option

User wants to show only a subset of child components


Show different variants

LH & RH assemblies

Hide Some Components


Simplification of assembly data

The goal with simplification is to:

Provide a method of hiding proprietary data

Reduce assembly complexity

Improve load performance

There are several methods to simplify geometry in NX:

Assembly Level

 Assembly Envelope (Wrap & Linked Exterior options)

 Simplify Assembly Wizard

 Simple Reference Set

 Faceted Representation

Component Level

 Simplify Body

 Extract Geometry (Timestamp)

 Wrap Geometry



Assembly Envelopes

What are they?

 Tools for reducing assembly complexity as well as hiding proprietary data. Essentially, they create geometry at the assembly level that can take the place of subcomponents

Important Properties

 Use automatic reference set to specify display of envelope

 Two forms:

 Wrap Assembly – provides coarse boundaries and

gives a shrink-wrapped appearance

 Linked Exterior - makes an exact copy of external faces and maintains the form of the original


 Useful when only an approximation of an assembly is required (Wrap)

 Provides a method of improving load performance by reducing assembly complexity

 Provides a method of hiding proprietary data


Simplify Assembly Wizard

Simplification – Assembly Level

What is this?

 A dedicated wizard user interface that guides you through the process of simplifying an assembly into a solid that represents the assembly

Important Properties

 The goal to unite all the bodies in the assembly and remove the interior faces

 All bodies are linked into the work part

 Covering bodies are used to plug holes and fill gaps until all the bodies are united into one and the interior faces are completely isolated from the exterior faces

 The result is a single lightweight and airtight solid


 Helps reduce load times at the expense of geometric detail

 Preserves complex exterior details while removing interior details


Context Control

Assembly Context Control deals with display, selection & filtering techniques

Assembly context is the set of components you want loaded and visible at a

particular juncture

The assembly context control functions in NX are key to quickly finding,

returning to, and understanding the environment of a specific area to be

worked on

Filtering Techniques

Find Component

Open by Proximity


Context Control

Filtering Techniques

As your assembly becomes larger and more complex, there is an increasing

need for you to control the component parts that you work with and see

Large assemblies depend on filters and other techniques to efficiently navigate

throughout large amounts of data

There are several methods in NX to filter data including:

Component Groups (Filters)

Filtered Assembly Navigator



Find Component

What is it?

 The Find Component tool sets context by letting you perform a search for a component based on any global property

Important Properties

 Scope criteria:  By Name  By State  By Attribute  From List

 By Size - based on the component's bounding box

 The Status line shows the number of components that are selected in the current contexts


 Allows you to locate one or more components quickly in order to establish context control

Find Selected Component


Filtering Techniques

Component Groups

What are they?

 A set of tools used to set, save and restore logical subsets of assemblies for assembly context

Important Properties

 Primarily used for loading and unloading of data

 Two categories:

 Functional - use assembly data

 Attribute, Zone & Proximity

 Organizing – combinations of functional filters  Match All of, Match any of & Exclude from

 Can be saved permanently or temporarily


 Provide productivity through performance - you only load what you need

 Visual clarity - you only see what you want to see

 Intelligent component selection


Filtering Techniques


What are they?

 A method of defining and naming regions of space within an assembly that can be used for filtering criteria

Important Properties

 Can be defined by auto-generating entire assembly or explicitly sizing

 Two Types: Box Zones & Plane Zones

 Zones filter components based on a component’s

bounding box or True Shape filter

 Options to select:

 Box: Inside, Interferes, Outside

 Plane: Above, Intersects, Below

 Defined and stored at the assembly level


 Provide a useful way of partitioning an assembly model into meaningful regions

 Very useful for volume comparisons


Filtering techniques

Open by Proximity

What is it?

 A tool that simplifies the process of loading a set of components that are located in a small region of a large assembly

 Loads all components within a specified distance of the bounding box of a selected component

Use Cases

 When you wish to load large components in the vicinity of the work part for overview purposes

 When you wish to do a "lightweight" or “solid” load of

nearby components to understand your design context

Important Properties

 Optional True Shape Filtering

 accuracy vs. time


 Simplifies the process of loading a set of components that are located in a small region of a larger assembly


Enabling True Shape Filtering

Set customer defaults for true shape (tso) file generation

(see on-line help for guidelines)

If necessary, refile existing parts

with option “-ts”

Creates tso file without re-saving part

Existing users need to ensure

they have set the save option

Setting up tso file generation


Filtering Techniques

Bookmarks and Product Outline


What are they?

 Bookmarks allows you to record, communicate and restore the working context from one NX session to another

Important Properties

 Allows you to duplicate a current assembly state in a later NX session

 Record options include:

 which component groups are applied

 what are the active Load Options

 which components are loaded

 User specific workflows – native & NX



 Allows you to quickly reestablish a desired working context from one session to another

 Provides a method of context sharing between

Product Outline

 Ghost image of assembly that can be switched on and off


Visualization settings and Memory utilization


Visual Performance Preferences

Large Model Settings

What are they?

 A number of preferences that can dramatically improve graphics performance/speed

Important Properties

 These viewing dynamics preferences are applicable on rotate, pan, zoom and navigate operations


 This greatly reduces the amount of memory needed to change view orientation in the graphics display

Large Model

 Fixed Frame Rate - this will allow the system to display a box of the component/body on repositioning of the

geometry in the graphics window

 View Frustum Culling – allows the system to disregard



Changing body color, translucency, or partial shading:

o Make the component the Displayed Part before changing anything or in an assembly. Also, make sure only the component (not the body or any portion of it) is selected.

Controlling Updates:

o In a large assembly, you can save time by delaying interpart updates and then updating at your convenience

Saving in Wireframe vs. Shaded

o Part files saved with shaded display active will take longer to load and use more memory

o Tests show that a shaded model can take up to 5 times longer to load than the same model in wireframe

Shaded Mode vs. Partially Shaded Mode

o A less memory intensive option to fully shading o This means that only bodies/components designated


Hardware Recommendations

Large Assembly Focus

With the rapid changes in hardware and software, any quantitative

recommendations become obsolete within months

The best recommendation (as an NX customer or any other CAD user) is for

you to monitor technologic advances specifically in the following areas:

Physical memory (#1)

Graphics card speeds and capabilities (#2)

CPU speed

Disk access speed and capacity


Hardware Recommendations

Large Assembly Focus

Tuning graphics card

•Windows Desktop

•Display Properties – Advanced •select graphics card Control Panel. •Under application or global presets

•Select NX.

•Start NX

•Preferences – Visualization


Large Assembly Drawings

The creation and update of large assembly drawings is computationally expensive by


In particular, the creation of hidden line renderings of views

As well as requiring all relevant components to be loaded into the session, the hidden

line calculation itself demands significant memory and processor resource

NX provides techniques for making the process more efficient by reducing the amount

of data that typically needs to be loaded to create or annotate a drawing and its views


Large Assembly Drawings Topics

Master Model Strategy

Delaying View Updates

Associative Extracted Edge Views

Faceted Representation Views

Predefined Drawing Templates


Master Model Strategy

What is this?

 Instead of creating the drawing in the assembly itself, the master model strategy takes advantage of a non-master document that references the non-master


Important Properties

 Create through File>New dialog box


 Promotes concurrent engineering, by enabling a user to modify the drawing without locking the master assembly - Drafting and modeling changes can happen in parallel

 Separates annotation data from the master assembly - which means you can load the master assembly without needing to load the drawing data into the session - this speeds up the loading process and reduces memory consumption


Delaying View Updates

What is this?

 A major contributor to performance and memory usage issues with large assembly drawings is the amount of resource required to update views (in particular, the hidden line renderings)

 The Delay View Update option allows you to minimize view updates

Important Properties

 Updates can be initiated explicitly at a more

convenient time or by using a UG/Open program

 View updates can also be delayed on a per-view basis


 Improves performance and memory usage by

reducing the amount of resource required to update views

 Prevents hidden line recalculations when the assembly changes


Associative Extracted Edge Views

What are they?

 An alternative way to display model geometry in a drawing view by creating a set of associatively extracted edges

 Instead of the model being directly visible in the drawing views, the system displays a 3D

representation of the model's visible edges

Important Properties

 Supports Concurrent Engineering

 Associative or Non-Associative methods

 The components only need to be loaded when a drawing update is performed


 Improves performance by allowing simple annotation, view edits, and the creation of detail views can be made on large assemblies without the assembly components being completely loaded


Faceted Representation Views

What are they?

 Renderings of a faceted representation of the assembly

Important Properties

 Can be used for dimensioning

 List others…

 Update drawing view at a more convenient time


 Facilitates the quick update and hidden line display of a drawing of a large assembly

 Using faceted representations when creating drawing views can dramatically improve the performance and memory utilization of assemblies drawings


Predefined Drawing Templates

What are they?

 A capability that results in automatic drawing view creation by creating a new master model drawing from a modeling view

Important Properties

 The template contains empty drawing views that are not linked to a model

 Drag and drop a model / assembly onto the template and the views populate with the model Drawing

Templates can include the following:

 Drawing Borders

 Imported Views

 Section Views

 Exploded Views

 Automatic Ballooning

 Applies dimensions and annotation

 Populate Parts List and Tables


 Saves considerable time by eliminating repetitive tasks creating a standard layouts of component parts / assemblies





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