Nx Practices

5/28/2018 Nx Practices

1/28

2007. Siemens Product Lifecycle Management Software Inc. All rights reserved

Siemens PLM Software

Whos Best Practices?

Mark Lawry



2/28

Page 2



Background: Two user communities in NX

Former I-deas users and former Unigraphics (UG) users bring different

"best practices" with them, often with strongly held opinions.


3/28

Page 3



Best practices review

Why were they adopted?

General design principles?Company or industry standards?

Software performance?

Are they still valid?

Has our design process changed?Have our standards changed?

Has the software performance changed?

Are new methods available?


4/28

Page 4



1. Use of datums

I-deas practices:

Start with BORN coordinate system (Base Orphan Reference Node)

BORN contains 3 planes, 3 axes, 1 origin

Create datums first in the history tree

Create datums relative to other datums

UG practices:

Start with primitive block or datum

Dont create unused datum planes Create datum planes when needed

Create datums relative to geometry


5/28

Page 5



1. Use of datums continued

NX changes (from UG or I-deas) thataffect old practices:

Datum coordinate systems are now oneentity in NX, not separate datum planes.

Unused datum coordinate system planes

are not flagged as unused items.

Datum coordinate systems can bereordered, even to be the first feature,and associativity added.(This is not possible in I-deas.)

Creation of relative datum coordinatesystems (Offset CSYS) has beenimproved.

Display of datum coordinate systems hasbeen improved to control size.


6/28

Page 6



1. Use of datums continued

NX best practices:

The BORN coordinate

system practice from I-deas

is no longer required based

on software behavior, but is

still a good design practice.

It is included in the Model

template.

Create other datum

coordinate systems as

Offset CSYS with

associativity to the first

datum coordinate system,

similar to the BORN method.


7/28Page 7



2. Associativity

I-deas practices:

Goal to create associative features.

Sketch in Place preferred over sketching on the work plane.

Use Focus to create associative geometry.

Use Feature Copy to subdivide part design.

Use ACF to create associative links between parts in an

assembly.

UG practices:

Associativity is not the only goal. Keep features independent because they are less prone to

surprises.

Avoid interpart links to prevent inadvertent changes to released

files.


8/28Page 8



2. Associativity continued

NX changes that affect practices:

Parent/child associativity is very visible in the

Part Navigator.

Focus within a partis not required.

Associativity between

parts is easier to create

without WAVE Geometry

Linker or ACF. (NX 6)


9/28Page 9



2. Associativity continued

NX best practices:

Build on the oldest, most stable geometry.

Datums should be preferred over faces and edges.

Avoid references to faces or edges of

detailed design features like chamfers or blends.

Associativity is most useful in the intermediate design phase

with highly engineered models.

For early concept models, it is not as necessary.

Consider using Synchronous Modeling with History-Freemode for concept models or for manufacturing changes, not

for highly engineered models. (NX 6)


10/28Page 10



3. Organizing sketches

I-deas practices:

Sketches are absorbed into features.

Convert sketches to reference curves to use in multiple features.

Use sketches to define design intent.

Create as many relationships as possible in a sketch.

UG practices:

Sketches are separate features.

Keep sketches simple and small, one per feature.


11/28Page 11



3. Organizing sketches continued


Sketches can be external or internal to features.

Constraints and dimensions can span from one sketch to another.

(You cannot do this in I-deas.)


12/28Page 12




NX best practices:

Use the same sketch for multiple features.


13/28Page 13




NX best practices: Reuse sketches and features using Copy and Paste.


14/28Page 14




NX best practices: Use constraints and dimensions between sketches.

Organize design intent in sketches in the most logical way.

Sketch 1

Sketch 2

Sketch 3


15/28Page 15



4. Sketch-based features vs. form features

I-deas practices:

Almost all features are sketch based.

Primitive features are discouraged.

UG practices:

Primitive features were used.

Best practice was to only use one primitive to start a model.

Sketched features were avoided by some customers.


16/28Page 16



4. Sketch-based features vs. form features continued


Primitive features now have some associativity.

Form features now use sketches. (Holecommand)

Form features indicate design/manufacturing intent.


17/28Page 17



4. Sketch-based features vs. form features continued

NX best practices:

Sketch-based features are still a best practice to define design

intent.

Form features offer a better way to indicate

design/manufacturing intent in some circumstances.

What is the best way to make the model understandable and

editable by others?


18/28Page 18



5. Bushy tree modeling

I-deas practices:Advanced I-deas users use bushy tree modeling.

UG practices:

Users never heard of it.


19/28Page 19



5. Bushy tree modeling continued


In NX, Boolean operations can be embedded within a feature or a

added as a separate feature.

The Part Navigator displays features in linear Timestamp order orgrouped as solid bodies.


20/28Page 20



5. Bushy tree modeling continued

NX best practices: Use a separate Boolean feature to use the equivalent of bushy

tree modeling. (UG instructors often recommend this, but they

dont call it bushy modeling.)

Turn off Timestamp Order to work with multiple bodies.


21/28Page 21



6. Patterns

I-deas practices:

Use of patterns is encouraged.

Patterns create one feature.

UG practices: Use of patterns was encouraged (instance arrays).

Patterns created one feature for each instance.

Suppressing individual instances in the pattern was discouraged.


22/28

Page 22 2008. Siemens Product Lifecycle Management Software Inc. All rights reserved


6. Patterns

NX software changes:

Feature arrays and geometry arrays are types of patterns.

The new sketch-based Hole command can create an entire pattern

of holes as one feature. (NX 6)


23/28



6. Patterns continued

NX best practices:

Patterns are an efficient way to model, and also capture design

intent.

Consider using the new sketch-based Hole command instead of

using a pattern command, especially for irregular hole patterns.


24/28



7. Controlling object visibility

I-deas practices: Display Filter is used primarily.

Sketches and tools are absorbed into features.

UG practices:

Layers were used primarily.

Company standards existed for layer use.

Sketches and Boolean tools were placed on hidden layers.


25/28



7. Controlling object visibility continued


There are several methods to control object

visibility:

Hide command

Show command

Hide and Show command

Layers

Reference Sets - Used to define what is

shown in an assembly.


26/28



7. Controlling object visibility continued

NX best practices:

Use the Hide and Show command or layers

to control object visibility.

Dont use both at the same time because

the Hide and Show command only works

with objects on visible layers.

Parts migrated from I-deas will have some

objects on specific layers, so you need to

know about layers. Understand Layers and Reference Sets

when using assemblies.


27/28



Conclusion

NX best practices:

Best practices based on design principles and design intent are still

valid.

Associativity, structured design, use of datums, reuse of

sketches and features

Some best practices based on software behavior are no longer

required, but may still be a good discipline.

BORN coordinate system

Software changes may open up new best practices.

Organizing sketches, using design features, hole patterns

Nx Practices

Documents

Transcript of Nx Practices