2008con 3d design practices samuels

7/31/2019 2008CON 3D Design Practices Samuels

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2008 FIRSTRobotics Conference

3D Design & Practices

Presented by:

Bill Samuels

Designer

BAE Systems


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45 minutes on these topics

General Design Process

3D Modeling Philosophies

Best Practices in Pro/ENGINEER Tips and Tricks for Pro/Engineer

Web resources, Cool Links & Acknowledgements


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Define the Task

White board

Documentation

Prototype Peer Evaluation

Team Design Reviews

Build


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Define the Task

Defining the task establishes a clear goal or goals.

Do not confuse defining the task with a solution for the task.

An example:

A pencil and a cup resting on a desk, the task is to get the pencil in the cup. Asolution would be placing the pencil in the cup using your hand.

Using the expression placing the pencil in the cup limits the designer to thinkingthat only the pencil is allowed to move.

Keep this list of goals and or tasks as generic as possible, this allows free thinking.


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White boardIn conjunction with the discussion of defining the task, white boarding thoughts conveysinformation not easily expressed in words. This is also a great place to capture tasks that

will assist in keeping the group focused.


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Documentation

During the discussion and white boarding session it is very critical to document all

information in an engineering notebook. This assures that data and progress will not be

lost between sessions. A team scribe is recommended.


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PrototypeOnce tasks have been defined and solutions considered, it is time to prototype the

solutions. This can be done using pencil and paper, 2D & 3D CADD tools, and

prototype/real world mockup.


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Peer Evaluation

A peer evaluation can be as simple as asking the person next to you to take a look at your

design and give their thoughts. Peer evaluations should happen on a daily basis, this

affords a second set of eyes a chance to capture design flaws and possible oversights.


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Team Design Reviews

Once the possible solutions have been captured and critically evaluated, it is time for a

team design review. This review should explain the choices made and recommendations

for the final design.


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Build

Once the team has committed to a solution for the task it is time to build.

Once building has begun the team may find issues with some of the sub assembly designs.

This will require going back and modifying some of the design concepts agreed upon inearlier design phases. This is when the design process would start over for that subassembly, repeat as required until a complete solution is attained.

"Once you have a good idea (design), stay with it. Dog it. Work with it until its right!- Walt Disney


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Top Down Design

Bottom Up Design


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Top Down Design

In top down design concept a top assembly envelope is cut into

specific volumes. These volumes are assigned specific functions.

In this philosophy a specific sub assembly does not limit the top

assemblys progress. Nor does it require any specific sub assembly to

be completed first.

This does require a lead designer to be responsible for maintaining

volumes for sub assemblies and there locations and progression in the

top assembly.


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Bottom Up Design

In bottom up design concept sub assemblies are added as they are

completed and no specific area is reserved for sub assemblies.

This requires a lead designer to be responsible for maintaining the top

assembly and insure he has the latest data from each designer.


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Choice of Philosophy

Both of these philosophies can work very well, as long as the entire

team adopts the same philosophy. And just as important is thateveryone on the team assists the lead designer in capturing the loose

ends.

One of the biggest pit falls is trying to combine the two philosophies.

And the biggest pitfall is not being proactive about resolving issues

you aware of. If its not clear to you how a component works, ask. Not

asking usually leads to lost work hours, over filing and a stressful

environment.


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Part modeling philosophy

Just as in an assembly a part can be top down or bottom up. In top

down for a part you start with the smallest mass that will encompassthe whole part and remove material to add definition.

In bottom up you start with a core shape and add features to

complete the definition of the part.


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Best Practices In Pro/ENGINEER

Always start with a plan

Create Features Individually

Create Features in a Logical Sequence

Carefully Create Parent/Child Relationships Use Insert Mode

Use Layers

Guidelines for Good Sketcher Use

Checklist for Good Pro/Engineer Models

Guidelines for a Good Part Model Guidelines for Good Drawing Creation


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Always start with a plan

It is very important to have at least a preliminary modeling

plan or strategy in mind before modeling. This plan shouldinclude the design intent of the model. Since the plan will

undoubtedly change as the project matures, it is not necessary

to have this plan fully developed before beginning. It will be

very easy to change the wrong plan into the right plan but be

very difficult to change no plan into the right plan.


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Create Features Individually

Do not create one feature that should be multiple features.

This will allow any combination of features to be suppressed ordeleted. Do not sketch multiple closed sections in sketcher.

Each closed section should be a separate feature.

For example: When creating a shaft with flanges and grooves,

create the base shaft as one feature and each flange and

groove as separate features. If the model is created as onefeature, there is an all or nothing scenario.


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Create Features in a Logical Sequence

For Example: A cover may require 4 features to model

correctly.If the cover is to have a lip around the top then the clearance

holes for the fasteners that hold down the cover may have to

come after the lip feature.


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Carefully Create Parent/Child Relationships

Create only the Parent/Child relationships that are necessary

for the models intent. Whenever creating a feature, alwaysclearly identify the references used to constrain that feature.

Whenever picking a reference, do so in a 3-D view. This

practice will make it easier to identify exactly what is picked.

Read the message window to validate picks, it lists what has

been picked. A set of related features should be able to besuppressed and resumed without having to also suppress or

resume unrelated features.


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Use Insert Mode

Use Insert Mode before modifying or when adding features.

Especially when working on a model with complex geometry ora large feature-count. By inserting close to the desired parent

geometry, regenerating features that have no real bearing on

the modification is avoided and the model regeneration time is

reduced. When adding features, it will keep features in a

logical order and keep parent/child relationships in check.After the modification or addition is done, resume the rest of

the features.


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Use Layers

Use default layers to automatically put various feature types

on specified layers. To verify that these default layers are setfor the part being worked on, either use the Layer menu in the

Model Tree or verify the layer setup in the Config.pro file. The

Layer menu will display the default layer options that have

been activated. If any of the default layers listed is not

activated, do so by editing the table. Create additional layerswith logical names that describe the features assigned to it.

They can assist in suppressing and resuming features. Keep in

mind the top assembly has every layer of every part.


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Guidelines for Good Sketcher Use Use sketched centerlines and construction circles to achieve the desired

dimensioning scheme.

Do not allow any weak dimensions to remain in a completed sketch. Either add

constraints, convert the weak dims to strong or add strong dimensions tocomplete a sketch.

As a rule of thumb, keep the number of dimensions in a sketch to a maximumof eight. Where more are needed to fully dimension a feature, create datumfeatures first, then reference the datum features when in Sketcher. Thistechnique will result in a robust model and minimize future difficulties with

the Sketch. It also follows the many simple features rule to create

models. Choose references sparingly. More references mean more feature to feature

relationships that can make the model more difficult to work with as itprogresses or changes. Choose only enough references to make the modelfollow the design intent.


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Choose references that wont disappear. References like edges that disappear

when rounded or drafted, are not the best choice. Datums and planner

surfaces are better. References from the base features are more stable than

those of later features.

When redefining a sketch, use Replace (Under Edit) rather than deleting asketched entity whenever possible. Replace will give the new entity the same

entity id number as the old entity. This will result in rerouting all the children

of the old entity to the new. Note that even if you have not referenced a

sketched entity someone else (working in Pro/ASSEMBLY, Pro/PIPPING,

Pro/MANUFACTURE, etc.) might have a reference to that entity.


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Checklist for Good Models Does it use the standard configuration file?

Have the six standard views been created in the correct orientation.

Has an appropriate pictorial view for the drawing been created and named foreasy identification?

Were layers created as needed and correctly shown or blanked for the

drawing?

Are descriptive names for features assigned in the Model Tree where possible?

Have similar features been compacted by using patters and groups?

Are Geometry Checks needed (is menu grayed-out) Have the standard parameters been created and their values been entered?

Have the standard relations been created?

Does it use the proper units systems (inch/lb/sec)?


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Has the correct density or material been assigned?

Has the correct file name been assigned?

Has the correct file location for storage, backup and retrieval been validated?

Are assemblies using library fasteners whenever possible?

Have suppressed features been deleted?


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Guidelines for a Good Part ModelThe goal is to create and name features so that any other user

can readily modify them at any time. Good modeling practicesare far more important early in the modeling process than atthe end as repair work.

Accomplish this by:

Following the standards in Pro/Engineer guidelines

Using the standard Start Parts when beginning a new part

Consciously setting up your parent/child relationships Creating a simple base feature

Creating simple sketches

Not sketching rounds or fillets when avoidable


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Guidelines for Good Drawing Creation Use the standard drawing set-up file The model should regenerate without errors or geometry checks prior

to beginning the drawing

No erased views should be kept in drawings Relate draft entities to objects or views, check for unattached text

( missing leaders) Make sure views do not overlap one another Use only projected, detail, or auxiliary views whenever possible

(avoid multiple general views)

Check for line width and text size uniformity (as in standard drawingset-up file) Use shown dimensions as opposed to created dimensions whenever

possible Delete all unused models from drawing


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Using default or created datums for view orientation

Dimensioning the part model as needed in the drawing

Creating drafts, rounds, and chamfers as late in the part model as

practical

Carefully considering the options when the above guidelines dont

make sense.


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Tips & Hints

Ways to impact text

Special Characters in a Note

Color

To Select items Search Secrets

Dimensioning

Axis Points

View Styles

Pivot Point Control Alt during assembly of items

Uncheck constraints to allow freedom

Use Lock Dims to assist in relocating items in a sketch


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Tips & Hints

Ways to impact text @s = a dim will display its symbol instead

of its numeric value when shown on adrawing. Also seeing A, B and C isbetter for family tables than seeingd1245, d1342 and d879.

@+ = superscript

@- = subscript @# = end script change @o = @o = replace the d with the letter o

of the created dimension and enter text,does not work on driving dimensions

@[ = start boxed text @] = end boxed text To control the number of digits displayed

in a table on a drawing

Create relation to name = &dim#On drawing use &name[.7] where the 7is the num of digs to display.


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Tips & Hints

Special Characters in a Note:

review the character map and locate the desired symbol,

create a note including the cross-referenced symbolsvalue, change the font that specific sysmbol.


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Tips & Hints

Color:

Create custom colors by

copying existing ones and

editing them.


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Tips & Hints

To Select Items:One by One

Use CTRL

Edge Loop:

Select Edge, Shift Select 2nd Edge

Loop Surfaces:

Select Surface, Shift - Select Edge

Seed & Boundary Surfaces:

Select Seed, Shift SelectBoundary, use control to addlast surface.

Edge From To Chain:

Select Edge, Shift Select 2ndEdge, RMB (Toggle)

Solid Surface:

Select Surface, RMB SolidSurface


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Tips & Hints

Search Secrets:

CTRL F

Components

FeaturesName

Type

Size

ID

Status


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Tips & Hints

Dimensioning:

NOTE: CONVERT STRAIGHT LINES TOCONSTRUCTION.

Perimeter:Entity(s), Convert To, Dimension

Tangent Angle:

Vertex, Entity, Entity, Place

Arc Angle:

Entity, Vertex, Vertex, Place

Arc Length:Use Perimeter Function.

NOTE: CONVERT STRAIGHT LINES TOCONSTRUCTION.


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Tips & Hints

Axis Points:Available in Internal

Sketches only

To be used for DimensioningScheme

Useful for assembly

references and in patterns


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Tips & Hints

View Styles:Blank, Wireframe,

Hidden, HLR

By Display

Multiple Styles available at once

User Activated

Visible Indication

Will impact Repaint

Performance


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Tips & Hints

Pivot Points

when copying features in

sketcher you can change the

pivot point by right clicking onit and then selecting the

desired location.


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Tips & Hints

Control Alt

Use control alt pressed at the same time to orient an item being

added to an assembly.

Control Alt & RMB to spin the item being added.

Control Alt & MMB to pan the item being added.


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Tips & Hints

Uncheck constraints to allow freedom

Rather than delete constraints, uncheck them to evaluate other

locations and orientations of an item.


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Tips & Hints

Use Lock Dims to assist in relocating items in a

sketch

Set filter to Dims, window entire sketch, RMB and hold, select lock.

Then unlock the dim controlling the location of the sketch. It can now

slide in that orientation without distorting.


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Web resources, Cool Links &

Acknowledgementswww.ptc.com/support Knowledge Base

/community Tutorials & Download

www.proesite.com Configs & Benchmark

www.ptcuser.org Exploders

www.profilesmagazine.com Pro/E E-zine

www.proengineer.com Pro/E Resources

www.mcadcentral.com Tips, Jobs, Forums

www.proe.com Tips, Forums

www.turbosquid.com/3d modelswww.mcmaster.com/ vendor items, models

www.3dcadbrowser.com models

www.3dcontentcentral.com/ models

www.mcaduser.com/ models

www.gdandt.com/quiz.htma geometric TOLERANCING quiz

www.matweb.com/search/MaterialGroupSearch.aspxmaterialsproperties page

www.cad-resources.com/ tutorials

Everything in this presentation is acompilation of exposure to all of theselinks and fellow users and theirpresentations I thank them all for makingtheir knowledge so accessible to me andYOU! I would only ask you pass onknowledge you gain to others as well.
http://www.ptc.com/supporthttp://www.ptc.com/supporthttp://www.ptc.com/communityhttp://www.proesite.com/http://www.ptcuser.org/http://www.profilesmagazine.com/http://www.proengineer.com/http://www.mcadcentral.com/http://www.proe.com/http://www.turbosquid.com/3dhttp://www.mcmaster.com/http://www.3dcadbrowser.com/http://www.3dcontentcentral.com/http://www.mcaduser.com/http://www.gdandt.com/quiz.htmhttp://www.gdandt.com/quiz.htmhttp://www.matweb.com/search/MaterialGroupSearch.aspxhttp://www.matweb.com/search/MaterialGroupSearch.aspxhttp://www.cad-resources.com/http://www.cad-resources.com/http://www.matweb.com/search/MaterialGroupSearch.aspxhttp://www.gdandt.com/quiz.htmhttp://www.mcaduser.com/http://www.3dcontentcentral.com/http://www.3dcadbrowser.com/http://www.mcmaster.com/http://www.turbosquid.com/3dhttp://www.proe.com/http://www.mcadcentral.com/http://www.proengineer.com/http://www.profilesmagazine.com/http://www.ptcuser.org/http://www.proesite.com/http://www.ptc.com/communityhttp://www.ptc.com/supporthttp://www.ptc.com/support

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