Radical workarounds 2-20

8/7/2019 Radical workarounds 2-20

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Radical workarounds for Draft, Fillet and Shell

Edward Eaton, Sr Industrial Designer

DiMonte Group Inc - www.dimontegroup.com


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The feature pyramid-1

Extruded cuts and bosses blind, through all,midplane

Revolves

Constant radius fillets

Chamfer

Single direction patterns

Mirror all

Face draft

Why is this called RADICAL workarounds?

because you should almost never do them!


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Extruded cuts and bosses up to surface

Offset surfaces

Planar surfaces

Projected curves

Sweep (simple)

Parting line draft

Hold line fillets

Variable radius fillets

Loft from two profiles

Mirrorfeature

Shell

Insert Bends




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Extruded cuts and bosses up to next, offsetfrom surface

Sweep with guide curves

Loft

Centerline loft

Cut with surface Trim surface

Extend surface

Untrim surface

Create solid from knitted surface

Derived sketch

3-D sketches

NEW Sheet metal features




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Loft with guide curve

Two direction patterns

Surface fill

Base parts

Mirror parts

Configurations

In context features

Join

Radiate surface

Split line

Rib

Curvature continuous face fillet with two holdline




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Split bodies

Combine bodies

Cut-thicken

Step Draft

Move Face

Fix in sketch

Using faces, edges in context

Imported surfaces/solids

Helix

Dome

Shape feature

Freeform

Curve through reference points

Scale




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Introduction

Through my work with DiMonte Group, I run into all sorts of problems acrossmultiple industries and processes.

Sometimes you just have to rise to the challenge your customer demands

from you. They dont hire DiMonte Group to do the easy stuff.

!! WARNING this is going to get ugly and complicated!!


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Common thread

What do Fillet, Draft, and Shellhave in common that sometimes

requires radical modeling?

They are APPLIED features.

They use existing faces and

edges no sketches to define

them


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Fillets need end faces

Lets get ugly and complicated right away!

- On a really simple model


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Add fillets (slightly different radius on each)


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The fillets need to continue until they find someplace to end

This is the end face

for the fillet on

the left

This is the end face

for the fillet on

the right


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And, by following its rules, the fillet does something that at first blushlooks CRAZY!

The Shaft

is GONE!!


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Understanding Fillet end faces

Edge to round


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Edge to round

Face that needs to becreated


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Edge to round


Fillet stops before blowing

through


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Fillet issues

Edge to round


Fillet stops before blowing

through

Surface is extended to

create cap


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Edge to fillet


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Edge to fillet



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Edge to fillet


Cap required to stop fillet


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Edge to fillet


Cap required to stop fillet

SW cant extend this

algorithmic face, so it

keeps edge instead


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End face sample 1

Why couldnt it extend?


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End face sample 2

Why are these

different?


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Sometimes just take the end faces out of the equation

Atomic Bomb

Fillet

Bonus off-topic

clean-up so

well do it quick


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Accessed buried faces for fillet

Featuremerged

Featurenot merged


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Fillet inside corners of shutoff window

Fillet in drafted shutoff

How to add cosmetic fillet and

maintain pristine parting line


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Why I present methodologies

I dont have to show you work around this perplexing issue


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Why I present methodologies

ANY of these five

techniques can be

employed to beat this

problem!


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Interaction of fillet and draft

Fillet causes this parts nice, flat parting line to droop


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Step draft alternative

Visualize how else you could use this


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Draft - Socket

Hopper drops into base

then twists to lock

Sweeter Dispenser


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Draft - Socket

The plan

Avoid lifters under tabs byjudicious use of parting line


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Draft - Socket

The plan The problem

We want to keep thisinterface tight


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Draft - Socket


Neutral plane draft - gap


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Draft - Socket


Parting line draft I wantthis!


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Draft - Socket

Neutral plane draft vs- parting line draft

* Draft angle exaggerated for clarity


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Draft - Socket

Neutral plane draft vs- parting line draft


Neutral plane

draft starts at

selected plane

Parting line

draft starts at

selected edge


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Draft - Socket

Parting line draft is ideal



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Draft - Socket


Allow reduced angle not addressing it

yetfor a darn good reason!


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Diagnosis


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Diagnosis


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Diagnosis

It works!


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Diagnosis

It still works!


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Diagnosis

It Fails!

* This is not a uniform applicable angle


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Diagnosis - WHY

It Fails!

Planar face

parallel faces curves

Parting line drafted face

scrunched up faces curves


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Diagnosis (just to be thorough)


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It works!


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Apply what we learned so far


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Ughh!

Has to extend existing faces to end feature!


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Provide the desired end-face with a cut Then re-apply draft

Provide end face that respects parting line


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It works!

Provide end face that respects parting line


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Continues

off at 14r

Not bad!

Nice face


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1. Break into the parts weve learned about


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1. Break into the parts weve learned about

* Resulting bodies separated for clarity


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2. Apply necessary drafts



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* No need to split central body - oops


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3. Combine back into one part


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3. Combine back into one part and evaluate


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4. Clean up (if necessary)


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4. Evaluate


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Draft - Summary

Keep that parting line

pure for your moldmaker!

When in doubt, think

about the tool geometryinstead of the part

geometry

Split part to provide end

faces for the appliedfeature

Fall back to split part to

separate into

manageable segments

But Ed!


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But Ed!

Talk about Allow reduced angle on parting line draft already!!!!

But Ed!


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But Ed!

Talk about Allow reduced angle on parting line draft already!!!!

It works!


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Judge performance and choose

So which of these workarounds is best?

That depends

Allow reduced angle

on parting line draft

Parting line draft

to split line

Split-Body, then

draft workaround


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That depends

Allow reduced angle


Parting line draft

to split line

Split-Body, then

draft workaround


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That depends

Allow reduced angle


Parting line draft

to split line

Split-Body, then

draft workaround


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1.Sh

ell takes all of th

eunselected faces

2.offsets

How Shell works step by step

5.knits

3.trims

4.deletes faces that are

eliminated by neighbors

6. Merges with solid

to create the void


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SHELL is the hardest working feature in SolidWorks

When you think about it, Shell is AMAZING

Im pretty forgiving about it

We just have to give it what it needs

Allow reduced angle


Parting line draft

to split line

Split-Body, then

draft workaround


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Why shell can skip a face

Ive seen complex faces

skipped before, but not thisegregiously

Note Verification on

Rebuild is activated


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Note on Verification on rebuild

Ick

Note Verification on

Rebuild is OFF

Use Tools>SketchTools>Face curves to diagnose the


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g

issue with the pod

Use split line to segregate the scrunched part of the


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three-sided surface on the pod

Use Delete Face to delete the scrunched part of the


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three-sided surface of the pod

Use Surface-Fill to replace the scrunched part of the pod


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with a Shell-friendly four sided surface


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The friendlier 4-sided geometry shells just fine!

When modeling, avoid those three-sided faces if you want


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to shell


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The saddle face is deliberately lofted long


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Trim back the long saddle

h h f f f


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Mirror body, then do a shell-friendly four-sided fill

B t Ed I th id d f !


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But Ed, I can see a three sided face!

B t Ed I th id d f !


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But Ed, I can see a three sided face!

P t t Sh ll


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Part to Shell

P t t Sh ll


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Part to Shell

P t t Sh ll


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Part to Shell

Part to Shell


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Part to Shell

Check this minimum radius of curvature thing


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???!



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Reverse direction


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Reverse direction


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Reversed Shell fails as expected


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Reversed Shell fails as expected

So Now what?


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So Now what?

Experiment with Cut


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p

Shell again


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g


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???!

On to the workaround!


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Split into two bodies


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p

Shell the rear one


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Shell the rear one


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This s

hould probably

confuse you

Now Shell the Front!


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Shelling less at a time helps out


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They both work!

Then combine into a single body


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Combine into one

body

Conclusion


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Shell is super smart, but sometimes we ask

it to do too much

Its not always complicated faces that cause shells to fail


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Shell is constantly being updated to address problems with complex faces

Shell will probably not ever beat this issue with a simple face*

* and in a few minutes well discuss

why that is incredibly useful!

Shell in two directions


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Use split body to

shell in twodirections

* Idea stolen wholesale from Phil Sluder and the nice folks at TriAxial

The dreaded Yellow Shell Warning


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This is tough for me to

deliver to customers



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No access to shell

diagnosis tools



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Fortunately, we know

how to always get a

shell to fail!



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Yes!



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Now we have access to

Shell Error Diagnostics

to help point us towards

the problem

Cache-ing of Shell Error diagnostics


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Suppress fillets

Still get the dreaded

Yellow Shell Warning



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Re-do workaround

Faces that are nolonger in the model

still show up!!!



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HAVE to start

a new Shell in order to

get updated

Error Diagnostics

Fixed


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BTW, the pocket

needed to go

Clean shell that I can

deliver

OR just split the part


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SHELL the split bodies


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Then combine and yes, it passes Tools>Check


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Then combine and yes, it passes Tools>Check


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I wish that I

could give you a

rule to find the

sweet spot for

splitting a part

...its half

instinct, half art

When you get

close, you just

know

Question time!


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END

www.dimontegroup.com

Acknowledgements Tonight I was pondering what my best SolidWorks World moments were. Other than one night in Vegas (that I cant talk about because of other people but what a


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o g t as po de g at y best So d o s o d o e ts e e Ote t a o e g t egas (t at ca t ta about because o ot e peop e but at a

night!), here they are. Notice that they are all connected by a common theme:

In 1999, I got bored/annoyed with a promising-sounding session I was in so I excused myself to go down the hall to a less-promising sounding surfacingpresentation being presented by some guy named Keith Pedersen.Boy that book needed a different cover! I was enthralled his content was phenomenal, and he somehow translated fairly complex issues (like Co, C1,C2tangency which involves calculus) into regularhuman language (driving a car) and then told you why that mattered to your product. That was just one of manyrevelations communicated clearly in a way that a novice (like me!) could understand. I cant soundhis praises enough. (Remember that I showed up late andwas still able to catch up instantly! Thats how good Keith is)Keith doesnt always present at SWx World, but when he does EVERYONE should go. I usehim as my model when I present unfortunately I always fall short.

Also in 1999, Mark Biasottis presentation on 10 common surfacing design problems introduced me to the concept of using surfaces in design. It gave me anudge in a direction that I hadnt yet tried, and the momentum of that push carried me through over a decade of solving vexing problems that were not even in thescope of that presentation! That is the mark of a good presentation it doesnt tell you HOW to do something, it opens your eyes on a path to figure out how tosolve problems particular to your job. I stole the use of cuts to diagnose shells failures from him. Ithas since been included in the Help menu, and of course henow works for SolidWorks so I made a hard choice not to credit him on the slide referring to it. Besides, he made such an indelible case for it ten years ago thattoday it truly IS doctrine. Thanks Mark for all that you have contributed to the SWx community, and personally to my career!

These two presentations laid the foundation for me to be open to understanding how SolidWorks works under the hood. Jim Wilkinson also had a good under-the-hood presentation in 2009 about speeding up things like fillets, etc, and it should get some credit (and frankly needs to be redone!) but it didnt pull the curtainback quite the same way as Mark and Keith did (sorry Jim still love you and all that you do!)

But my #1 SolidWorks World moment of all time was a presentation by Cholly Nachman in 2000 in Orlando. I dont remember its name because ithad to do withwriting macros something I was a bit curious about at the time, but over the last decade I still havent pursued.But MY GOD when he was describing how macros work he introduced me to the BREP, to the fact that all SolidWorks features are macros, and (I think) thethree different face types that SolidWorks creates.He did it in a jovial, casual, offhand way (as is his way - meet Cholly and you will understand joy that guy is just a big bubble of enthusiasm).

Chollys content tore the top off my skull!!!! I now understood the man behind the curtain!I went back to work and everything made sense in SolidWorks. I was solving problems left and right, and since havent found any problem since that I cant beat.

My first SolidWorks World presentation was based on what I learned from these guys because I it was imperative to share it. I cant calculate what I earned in increased

productivity/competency over the last decade because of the windows that were opened by them. Ican share that I have had people tell me that I saved their jobs by

sharing stuff. It takes me over 100hours to compile, edit, test, refine, and otherwise prepare an hour and-a-half presentation. Getting feedback that a persons job was

saved because of a presentation is sometimes the only thing that keeps me going when slogging through formatting the next one.

And, in that light, I thought it important to acknowledge my mentors. SolidWorks World in general, and these guys in particular, made the last decade+ of my career

happen.

In my presentations Ive built on what Mark, Keith, Jim, and Cholly introduced me to (I kind of prefer to say I stole their stuff because that is how it feels). But I wouldnt

have been able to have had this great decade without you guys and the presentations that you spent many hours crafting into tight, coherent hour-and-a-half segments.

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