IS INVENTOR REALLY USEFUL??

[Anonymous]

Is it just me or is Inventor a house of cards? The system works well for me until I make an assembly, then when I want to change or replace a part I lose the constraints and the house of cards crumbles and all is to do again. I've taken a class, I have three big fat books on Inventor and still I cannot see how this system is useful to make assemblies. Is this a common problem?

[Anonymous]

A troll no more, you have raised yourself up from that level to the level of
hothead like me

Just Remember that only a select few ever attain the level of Guru the likes
of Sean D!

I have received engine models from the manufacturer that have all parts in
an assembly constrained from the origin not each other which is sooooo cool
to work with.

All the gasket thicknesses are taken into account and if you want to change
accessories i.e. alternator, turbo placement etc. all you have to do in
flush constrain the origin planes and the parts are in perfect orientation
to each other.

Oh for the luxury of being able to do it the right way and not the quickest
way every time!


wrote in message news:4853723@discussion.autodesk.com...
A troll you say. A troll? I resemble that remark. Obviously I started this
post in a fit of frustration but I appreciate the input from all. I have
some work to do and it reassuring to know it'll get better with experience.

Another technique I'm playing with is to ground all parts of my assembly. Of
course this will only work for stuff that's not supposed to move. And I find
that once everything is grounded they surely do not move.

[Anonymous]

Hi Gary,

Get him to work for ADSK!!!!, he sums up so well in 2 pages what I was
struggling to understand in about 3 books....
I believe that a good workflow is the hardest point to achieve in IV and
that should be cleared out into the differents documentations
Thanks again Walt.

Fabien.

"Gary R Smith (Autodesk)" a écrit dans le
message de news:4853491@discussion.autodesk.com...
Great post Walt!

I forwarded it to the documentation team as an example.

[Anonymous]

>"FABIEN SERRANO" wrote in message
>news:4854170@discussion.autodesk.com...
>Hi Gary,
>
>Get him to work for ADSK!!!!, he sums up so well in 2 pages what I was
>struggling to understand in about 3 books....
>I believe that a good workflow is the hardest point to achieve in IV and
>that should be cleared out into the differents documentations
>Thanks again Walt.
>
>Fabien.


Thanks everyone; glad I could help. I started an outline for a book a while
back, but actually writing the thing is turning into a daunting task. I am
looking for work at the moment, but I'm not sure Autodesk wants a rogue like
me.

Cheers,
Walt

[Anonymous]

"but I'm not sure Autodesk wants a rogue like
me. "

Hiring you would be a good move for Adesk, both from a practical standpoint
and a political one (which I guess are one in the same)

[Anonymous]

Man, to get one of the old school INV guru's like Walt into a position with
the Autodesk team would be a dream come true. As long as it was a real
position with real influence and not just a token gesture. I know Autodesk
think they have staff that know the product well, but I for one would sure
be happy to know someone like Walt was in the mix as a voice of reason as to
what should ot could be done.

Heck I am no avid supporter of subscription plans, but I would be willing to
split the cost of his salary across the amount of subscription's Inv has to
get him on-board 😉

Question is, Walt..... Do ya feel Lucky?.... Huh?.... Do ya feel you could
handle the dark side of the Swarf?

BrianC


"Albert Allen" wrote in message
news:4854654@discussion.autodesk.com...
"but I'm not sure Autodesk wants a rogue like
me. "

Hiring you would be a good move for Adesk, both from a practical standpoint
and a political one (which I guess are one in the same)

[Anonymous]

Considering he only lives about 20 miles from Inventor headquarters, I think
he's already close to the dark side. 🙂

Pat

[Anonymous]

Depends upon the software being used. I've found other software's that handle constraint dependency alot better than IV. I see very little feedback coming to the user when using IV so you end up with poor constraining results. Example: when a part in an assembly is grounded notice how you can still constrain its axis if those axis are in line with each other when it was originally grounded! granted you will see a ! but are you warned about this! other software's treat this as a huge problem and prompt the user to address it. Ever had to rebuild an assembly several times to get it to resolve? Where are the warnings of when you need to "rebuild all" several times? This feedback can lay the proper foundation for the rest of the cards to fall on before it's too late and they all crumble.

[Anonymous]

Paremetric feature based 3D modelling is not a house of cards it is a car. First you have to come up with the cash to buy it, then you have to change the oil and fuel it up and things will just keep breaking. Some brands are more reliable, some are faster or sexier. A shape and size for everyone so to speak.

Any time you are driving down the road the car may break down on you and leave you stranded. Some times you are travelling so fast as you forge ahead in your car you miss a turn. Sometimes you run into a big traffic jam with your car and think you would be better off walking. In the end despite all the costs of the car, the maintenance, and the breakdowns you still choose to take your car instead of walking.

You could just use a pencil and paper for design work but .....

[Anonymous]

I think I will take the Honda over the Yugo!

[Anonymous]

I'm having a problem trying to follow the notion of apply assembly
constraints to origin work planes. It take me 24 or more clicks to apply
just 1 constraint (sometimes more/sometimes less). What technique do you and
others use to apply assembly constraints to origin workplanes?

Here's mine:
1. RMB in browser
2. LMB Collapse All
3. Hover / RMB above part in graphics area
4. LMB Select Other 1+ times
5. LMB Cycle
6. LMB Accept
7. RMB
8. LMB Find in Browser
9. LMB Expand
10.LMB Expand
11.Hover / RMB above part in graphics area
12.LMB Select Other 1+ times
13.LMB Cycle
14.LMB Accept
15.RMB
16.LMB Find in Browser
17.LMB Expand
18.LMB Expand
19.LMB Constraint Icon
20.LMB Choose WP
21.LMB Scroll browser up (down) 1+ times
22.LMB Choose WP
23.LMB Flush constraint in dialogue
24.LMB Apply

"Walt Jaquith" wrote in message
news:4852772@discussion.autodesk.com...
Inventor is not a house of cards, but it's surly possible to build an
assembly that is. On the other hand, it's also possible to build assemblies
that are nearly bulletproof. As you gain experience, you'll learn how.
Dealing efficiently with assembly constraints is one of the primary skills
that an Inventor user needs to learn. Here's my most valuable tip to get
you on your way:

Good assemblies start with good parts. Each Invrntor part is a heirarchy of
fearures, each built on the ones before them. Now look at the browser tree
of a part. You started with a blank part, and added a base feature, then
other features. As you go down the browser, the dependancies between the
features get more complex, and therefore the features themselves get
inherantly less stable. It's easier to get the features at the bottom of
the tree to go sick than it is to get the first few at the top to act up.
Assemblies are the same way. The more parts you add, the more complex your
dependencies get, and the more potential you have for instability. What's
the solution? To work whenever possible from the top of the browser.

Each part, no matter what it looks like, has one set of perfectly stable
features--it's origin geometry. If you constrain two parts together in an
assembly by thier origin geometry instead of their features, your
constraints will never get sick, no matter how you change the parts, and
you'll have created a truly bulletproof assembly. Obviously, for this to
work, the origin geometry has to be positioned in some logical place in
relation to the part itself. This is done when the part is first created,
and involves the first vital decisions that are made about how a part is
going to be laid out. Where the origin geometry is going to end up is an
important consideration.

The next best feature of the part is the first one. It depends only on the
origin geometry, and so is very hard to destabilize. Choosing the right
orientation and attitude for that first feature is another big decision. If
the base feature is done right, subsequent features can be built on it
directly rather than on each other in a series of dependancies. What you're
trying to avoid here is a constraint in an assembly that's based on a
feature in a part that's based, in a tenuous line of dependancies, through
six other features before it finally gets to the stable, foundational base
feature of the part. In a situation like that, almost any little change you
make to the part is going to adversly effect the assembly constraint. If,
on the other hand, the constraint is made to a surface of the base feature
or (better yet) to the part's origin geometry, few (if any) changes to the
features of the part will cause that constraint to go sick. Can the base
feature be made in such a way that all other features are placed directly on
it rather than being built up on each other like a...card house? If not,
can the chain of dependancies be kept to only a few links? Assemblies and
parts work exactly the same way in this.

Here's an example: I'm building an assembly that's a shaft with gears,
pulleys, seals and bearings mounted on it. Obviously, I want an origin axis
running right down the middle of the shaft. So create my shaft so that the
part's X axis is the centerline of the shaft. Now I make my gears, etc. the
same way, and when I insert them into the assembly, I constrain their X axis
to the X axis of the shaft rather than picking features on the parts. The
result as far as putting the parts together is exactly the same, but the
configuration is much more stable. I can change the features on the shaft
all I want, but the parts that are mounted to it are going to stay lined up.
Notice also that in this senario, all the subsequent parts are constrained
directly to the first part in the assembly, not to each other. As I said,
when you can manage this, it's the best way to work. Any dependant part can
be modified or deleted altogether without effecting the rest of the
assembly. The moral of the story is to keep your matrix of dependencies as
shallow as possible. The result will be more stable parts and assemblies.

It's not often practical to get a assembly that simply can't implode under
any circumstances. You will get the occasional sick constraint. But you
can make an assembly thats really hard to hurt by planning your dependancies
carefully and logically. This is what makes Inventor fundamentally
different from AutoCad (for instance). It's really just a relational
database. This means that Inventor attempts to define the relationships
(I've called them 'dependencies') between parts, features and so on, in
addition to defining the parameters of the parts themselves. In its guts,
Inventor probably has as much in common with MS Access as it does with
AutoCAD; it just happens to represent things graphically. Once you get a
good handle on those relationships, your assemblies will quit giving you
fits.

Cheers,
Walt

[Anonymous]

About the same a graphical user interface to copy files and change
directories. What ever happen to MKDIR and type in the directory name. Now
you have to click on: File>New BMB click, select rename then type in the
name you want. Operating system that now takes over 1gb, with a minimum of
256mb memory. I think they call it progress. I can remember doing Autocad
Version 2.62 on a 386DX16 with 4mb memory and a 32mb hard drive and a 516k
graphics card thinking I had a really smoking fast CAD system.

Blair

"John-IV8SP1" wrote in message
news:4992272@discussion.autodesk.com...
I'm having a problem trying to follow the notion of apply assembly
constraints to origin work planes. It take me 24 or more clicks to apply
just 1 constraint (sometimes more/sometimes less). What technique do you and
others use to apply assembly constraints to origin workplanes?

Here's mine:
1. RMB in browser
2. LMB Collapse All
3. Hover / RMB above part in graphics area
4. LMB Select Other 1+ times
5. LMB Cycle
6. LMB Accept
7. RMB
8. LMB Find in Browser
9. LMB Expand
10.LMB Expand
11.Hover / RMB above part in graphics area
12.LMB Select Other 1+ times
13.LMB Cycle
14.LMB Accept
15.RMB
16.LMB Find in Browser
17.LMB Expand
18.LMB Expand
19.LMB Constraint Icon
20.LMB Choose WP
21.LMB Scroll browser up (down) 1+ times
22.LMB Choose WP
23.LMB Flush constraint in dialogue
24.LMB Apply

"Walt Jaquith" wrote in message
news:4852772@discussion.autodesk.com...
Inventor is not a house of cards, but it's surly possible to build an
assembly that is. On the other hand, it's also possible to build assemblies
that are nearly bulletproof. As you gain experience, you'll learn how.
Dealing efficiently with assembly constraints is one of the primary skills
that an Inventor user needs to learn. Here's my most valuable tip to get
you on your way:

Good assemblies start with good parts. Each Invrntor part is a heirarchy of
fearures, each built on the ones before them. Now look at the browser tree
of a part. You started with a blank part, and added a base feature, then
other features. As you go down the browser, the dependancies between the
features get more complex, and therefore the features themselves get
inherantly less stable. It's easier to get the features at the bottom of
the tree to go sick than it is to get the first few at the top to act up.
Assemblies are the same way. The more parts you add, the more complex your
dependencies get, and the more potential you have for instability. What's
the solution? To work whenever possible from the top of the browser.

Each part, no matter what it looks like, has one set of perfectly stable
features--it's origin geometry. If you constrain two parts together in an
assembly by thier origin geometry instead of their features, your
constraints will never get sick, no matter how you change the parts, and
you'll have created a truly bulletproof assembly. Obviously, for this to
work, the origin geometry has to be positioned in some logical place in
relation to the part itself. This is done when the part is first created,
and involves the first vital decisions that are made about how a part is
going to be laid out. Where the origin geometry is going to end up is an
important consideration.

The next best feature of the part is the first one. It depends only on the
origin geometry, and so is very hard to destabilize. Choosing the right
orientation and attitude for that first feature is another big decision. If
the base feature is done right, subsequent features can be built on it
directly rather than on each other in a series of dependancies. What you're
trying to avoid here is a constraint in an assembly that's based on a
feature in a part that's based, in a tenuous line of dependancies, through
six other features before it finally gets to the stable, foundational base
feature of the part. In a situation like that, almost any little change you
make to the part is going to adversly effect the assembly constraint. If,
on the other hand, the constraint is made to a surface of the base feature
or (better yet) to the part's origin geometry, few (if any) changes to the
features of the part will cause that constraint to go sick. Can the base
feature be made in such a way that all other features are placed directly on
it rather than being built up on each other like a...card house? If not,
can the chain of dependancies be kept to only a few links? Assemblies and
parts work exactly the same way in this.

Here's an example: I'm building an assembly that's a shaft with gears,
pulleys, seals and bearings mounted on it. Obviously, I want an origin axis
running right down the middle of the shaft. So create my shaft so that the
part's X axis is the centerline of the shaft. Now I make my gears, etc. the
same way, and when I insert them into the assembly, I constrain their X axis
to the X axis of the shaft rather than picking features on the parts. The
result as far as putting the parts together is exactly the same, but the
configuration is much more stable. I can change the features on the shaft
all I want, but the parts that are mounted to it are going to stay lined up.
Notice also that in this senario, all the subsequent parts are constrained
directly to the first part in the assembly, not to each other. As I said,
when you can manage this, it's the best way to work. Any dependant part can
be modified or deleted altogether without effecting the rest of the
assembly. The moral of the story is to keep your matrix of dependencies as
shallow as possible. The result will be more stable parts and assemblies.

It's not often practical to get a assembly that simply can't implode under
any circumstances. You will get the occasional sick constraint. But you
can make an assembly thats really hard to hurt by planning your dependancies
carefully and logically. This is what makes Inventor fundamentally
different from AutoCad (for instance). It's really just a relational
database. This means that Inventor attempts to define the relationships
(I've called them 'dependencies') between parts, features and so on, in
addition to defining the parameters of the parts themselves. In its guts,
Inventor probably has as much in common with MS Access as it does with
AutoCAD; it just happens to represent things graphically. Once you get a
good handle on those relationships, your assemblies will quit giving you
fits.

Cheers,
Walt

[Anonymous]

I leave the origin planes visible in the parts, then when in assy mode, I just apply constraints choosing part &/or planes & axis as I go. It's no worse than choosing geometry. Does not work for insert tho.

[Anonymous]

Very well stated Walt.

Do you have any suggestions on how to convince my users to follow these guides?

I've been saying this from the beginning (work around the origins, etc) but it seems to fall on deaf ears.

[R.Corriveau]

"It's no worse than choosing geometry."

It is if you have 100's of parts. I for one do not want to see all them worplanes. Could you imagine? 500 parts x 3 workplanes gives me 1500 workplanes on the screen at one time not to mention user workplanes.

Again per a previous wish post I made. Can we get a transparent "Find in Browser" while in the constrain command?

Please. Pretty please.

[kgrunawalt]

IMate-based constraints can also survive part/assembly replacement if the original and the replacement have compatible iMates.

Katrin Grunawalt (Autodesk dev).

[Anonymous]

What a wonderful analogy! I have worked with people who still didn't REALLY believe that AutoCAD was better than a drafting board. It made teaching them IV very painful.

There is a certain about of "buy in" one needs when learning a software. If the learner doesn't really believe deep down that 3D is going to save time in the long run.....it will be a very painful process for them and they probably won't be very good at it in the end.

[Anonymous]

Does anyone else have any alternative workflows for this task that they'd
like to share. I'm keenly interested in what you have!

Thanks very much.



"John-IV8SP1" wrote in message
news:4992272@discussion.autodesk.com...
I'm having a problem trying to follow the notion of apply assembly
constraints to origin work planes. It take me 24 or more clicks to apply
just 1 constraint (sometimes more/sometimes less). What technique do you and
others use to apply assembly constraints to origin workplanes?

Here's mine:
1. RMB in browser
2. LMB Collapse All
3. Hover / RMB above part in graphics area
4. LMB Select Other 1+ times
5. LMB Cycle
6. LMB Accept
7. RMB
8. LMB Find in Browser
9. LMB Expand
10.LMB Expand
11.Hover / RMB above part in graphics area
12.LMB Select Other 1+ times
13.LMB Cycle
14.LMB Accept
15.RMB
16.LMB Find in Browser
17.LMB Expand
18.LMB Expand
19.LMB Constraint Icon
20.LMB Choose WP
21.LMB Scroll browser up (down) 1+ times
22.LMB Choose WP
23.LMB Flush constraint in dialogue
24.LMB Apply

"Walt Jaquith" wrote in message
news:4852772@discussion.autodesk.com...
Inventor is not a house of cards, but it's surly possible to build an
assembly that is. On the other hand, it's also possible to build assemblies
that are nearly bulletproof. As you gain experience, you'll learn how.
Dealing efficiently with assembly constraints is one of the primary skills
that an Inventor user needs to learn. Here's my most valuable tip to get
you on your way:

Good assemblies start with good parts. Each Invrntor part is a heirarchy of
fearures, each built on the ones before them. Now look at the browser tree
of a part. You started with a blank part, and added a base feature, then
other features. As you go down the browser, the dependancies between the
features get more complex, and therefore the features themselves get
inherantly less stable. It's easier to get the features at the bottom of
the tree to go sick than it is to get the first few at the top to act up.
Assemblies are the same way. The more parts you add, the more complex your
dependencies get, and the more potential you have for instability. What's
the solution? To work whenever possible from the top of the browser.

Each part, no matter what it looks like, has one set of perfectly stable
features--it's origin geometry. If you constrain two parts together in an
assembly by thier origin geometry instead of their features, your
constraints will never get sick, no matter how you change the parts, and
you'll have created a truly bulletproof assembly. Obviously, for this to
work, the origin geometry has to be positioned in some logical place in
relation to the part itself. This is done when the part is first created,
and involves the first vital decisions that are made about how a part is
going to be laid out. Where the origin geometry is going to end up is an
important consideration.

The next best feature of the part is the first one. It depends only on the
origin geometry, and so is very hard to destabilize. Choosing the right
orientation and attitude for that first feature is another big decision. If
the base feature is done right, subsequent features can be built on it
directly rather than on each other in a series of dependancies. What you're
trying to avoid here is a constraint in an assembly that's based on a
feature in a part that's based, in a tenuous line of dependancies, through
six other features before it finally gets to the stable, foundational base
feature of the part. In a situation like that, almost any little change you
make to the part is going to adversly effect the assembly constraint. If,
on the other hand, the constraint is made to a surface of the base feature
or (better yet) to the part's origin geometry, few (if any) changes to the
features of the part will cause that constraint to go sick. Can the base
feature be made in such a way that all other features are placed directly on
it rather than being built up on each other like a...card house? If not,
can the chain of dependancies be kept to only a few links? Assemblies and
parts work exactly the same way in this.

Here's an example: I'm building an assembly that's a shaft with gears,
pulleys, seals and bearings mounted on it. Obviously, I want an origin axis
running right down the middle of the shaft. So create my shaft so that the
part's X axis is the centerline of the shaft. Now I make my gears, etc. the
same way, and when I insert them into the assembly, I constrain their X axis
to the X axis of the shaft rather than picking features on the parts. The
result as far as putting the parts together is exactly the same, but the
configuration is much more stable. I can change the features on the shaft
all I want, but the parts that are mounted to it are going to stay lined up.
Notice also that in this senario, all the subsequent parts are constrained
directly to the first part in the assembly, not to each other. As I said,
when you can manage this, it's the best way to work. Any dependant part can
be modified or deleted altogether without effecting the rest of the
assembly. The moral of the story is to keep your matrix of dependencies as
shallow as possible. The result will be more stable parts and assemblies.

It's not often practical to get a assembly that simply can't implode under
any circumstances. You will get the occasional sick constraint. But you
can make an assembly thats really hard to hurt by planning your dependancies
carefully and logically. This is what makes Inventor fundamentally
different from AutoCad (for instance). It's really just a relational
database. This means that Inventor attempts to define the relationships
(I've called them 'dependencies') between parts, features and so on, in
addition to defining the parameters of the parts themselves. In its guts,
Inventor probably has as much in common with MS Access as it does with
AutoCAD; it just happens to represent things graphically. Once you get a
good handle on those relationships, your assemblies will quit giving you
fits.

Cheers,
Walt

[Anonymous]

"John-IV8SP1" wrote in message
news:4992272@discussion.autodesk.com...
I'm having a problem trying to follow the notion of apply assembly
constraints to origin work planes. It take me 24 or more clicks to apply
just 1 constraint (sometimes more/sometimes less). What technique do you and
others use to apply assembly constraints to origin workplanes?

Here's mine:
1. RMB in browser
2. LMB Collapse All
3. Hover / RMB above part in graphics area
4. LMB Select Other 1+ times
5. LMB Cycle
6. LMB Accept
7. RMB
8. LMB Find in Browser
9. LMB Expand
10.LMB Expand
11.Hover / RMB above part in graphics area
12.LMB Select Other 1+ times
13.LMB Cycle
14.LMB Accept
15.RMB
16.LMB Find in Browser
17.LMB Expand
18.LMB Expand
19.LMB Constraint Icon
20.LMB Choose WP
21.LMB Scroll browser up (down) 1+ times
22.LMB Choose WP
23.LMB Flush constraint in dialogue
24.LMB Apply



It's never been effortless, although the workflow you list seems a bit
excessive. Maybe I've been doing it so long its automatic to me, and I
blank out the gory details . I rarely use the 'select other' command if
I can help it...it's a kludge at best. I also rarely turn visibility on for
origin geometry. Basically, I work out of the browser when constraining
using origin geometry. This involves a bit of scrolling up and down the
browser, which I make less painful when I can by grouping my assemblies into
logical subs so that stuff I'm not working on can be collapsed or even
turned off. A long time ago I put in a wish for an 'always on top' option
for the origin geometry of the currently open top-level file. Haven't seen
anything yet 😞

Basically, real proficiency with constraints is a vital skill in this type
of software. Assembly constraints are a pain, and the only righteous remedy
is to get very good at them. With Autocad, the keyboard shortcut whiz was
often (arguably) the fastest operator. In the parametric world, the master
of constraints will be king. And like the old days when inheriting a dwg
file from a user with bad layer discipline who liked to explode blocks and
dimensions would cause frustration and cursing, in Inventor working on an
assembly created by a lazy constrainer will surely ruin your day.

Sorry I can't offer you a magic wand. There's just no quick way to make
constraints easy. Autodesk has done some work lately to make things easier.
In my opinion they need to recognize the pivotal nature of this part of the
software in the perception of new users, and focus more attention here.

Cheers,
Walt

[Anonymous]

wrote in message news:4992305@discussion.autodesk.com...
Very well stated Walt.

Do you have any suggestions on how to convince my users to follow these
guides?

I've been saying this from the beginning (work around the origins, etc) but
it seems to fall on deaf ears.


Motivating people, now that's hard.

They have to want to learn good assembly techniques. Better yet, they have
to realize that their future success in the industry depends on it. As I
stated elsewhere, lazy assembly constrainers are shaping up to be the solid
modeling equivalent of the CAD jockeys with lousy layer discipline who
exploded blocks and dimensions in Autocad, and didn't understand what paper
space was for. No one is going to want to work on files they've touched.
Folks who really understand this skill are going to be the gurus of the next
generation of modelers.

Cheers,
Walt

[Anonymous]

Good point, Walt. And might I add that a few exploding assemblies can also
be a motivator, especially if it leaves a bad enough taste in their mouth.
I've let some certain individuals fail deliberately and come in with your
prescription for success.

The key is timing. Folks are receptive right after these bad experiences. Of
course there's your coverup artist who tries to hide when they've boxed
themselves into a corner. They're the hardest to influence.

"Walt Jaquith" wrote in message
news:4993496@discussion.autodesk.com...
wrote in message news:4992305@discussion.autodesk.com...
Very well stated Walt.

Do you have any suggestions on how to convince my users to follow these
guides?

I've been saying this from the beginning (work around the origins, etc) but
it seems to fall on deaf ears.


Motivating people, now that's hard.

They have to want to learn good assembly techniques. Better yet, they have
to realize that their future success in the industry depends on it. As I
stated elsewhere, lazy assembly constrainers are shaping up to be the solid
modeling equivalent of the CAD jockeys with lousy layer discipline who
exploded blocks and dimensions in Autocad, and didn't understand what paper
space was for. No one is going to want to work on files they've touched.
Folks who really understand this skill are going to be the gurus of the next
generation of modelers.

Cheers,
Walt