Need Help with the Boundary Surface Tool

If someone would please guide me to a video tutorial or a Powerpoint
Presentation regarding the Boundary Surface tool, life would be good.
Evidentally, there have been numerous problems with users using the
loft tool on the Surfaces tool bar, for lofting in surface geometry,
that now a friend of mine tells me that her VAR claims that
Solidworks recommends using the Boundary Surface tool for Surfaces,
and the Loft Tool only for Solid Geometry. Not a very good condition
for a person trying to learn Surfaces which most are finding
difficult to begin with. I don't know enough of Surfaces in general
yet to understand the Solidworks help files very well. Anyway, if
anyone could help me out on this, I would be beholding to them.
Benjamin Halpin

 

Hello Ben,

Not sure who, how, what, where or why but there are some definate mis
statements there, if what was said is true. You should most certainly
read through the help topics on the Boundary surface to understand how
the feature works. What the underlying functionality is doing behind
the scenes. But just to help clarify, from the first initial look in
some ways they look like they perform or create the same surface. Some
differences that you will notice:

1) Controls that you have at the end conditions (Are at least equal if
not surpass the way that loft tool works)
2) Not as much sketch geometry is needed to define the boundary.
3) There is a Hair Drying video on the Solidworks main web site that
shows some of how the function works.

You should also check the Dimonte group web site. No one lays the
smack down as well as Ed with his tutorials.

 

I dont agree with your VAR. The boundary does not always give you the
smoothest surfaces, especially when you start changing tangency
values. I believe that this is why Solidworks included it as a
separate command, though they would have liked to have just improved
the Loft function.

Boundary allows you to create a surface with only a certain subset of
a long edge, and a curve that does not have to lie at either end of
the curve ie you can grab the handles and slide them along an edge.
It extrapolates design intent pretty well. Boundary also allows
curvature continuity along what would be considered guide curves in
loft. I use Boundary extensively, but substitute lofts when the
boundary solution looks crinkly.

 

I agree with Thomas. Plus, a couple more comments:

Mark B has been trying to get people excited about the boundary surface.
It really does have potential, but it isn't a regular in my tool set
yet. It fails too frequently, mainly when it thinks that the tangencies
from two different directions cannot be reconciled at a corner. Very
frustrating.

I find the interface of the boundary feature difficult to navigate. It
takes way longer to set up than the Fill surface, and those curvature
combs! You can't see anything when they're on, and they're on by
default, and don't remember your last setting. All the colors and combs
and stripes and whatnot on the screen make my head hurt. I could live
with a cacophanous interface if the feature delivered in the end, and it
does deliver about 20% of the time. I prefer to use Fill which is far
more reliable, works in a wider range of situations and is far easier to
use. I have had isolated instances where Boundary gave a better result
than loft or fill, but that was after a lot of trying. You also have to
tweek the options to get the best result.

The one word for the Boundary feature I have is: inscrutable. I don't
know when it will work, or why, or what settings it will take. I'm
optimistic and keep trying, but I have more confidence in Fill. Mark's a
good guy, but he is over confident in this limited and frustrating tool.

 

The same thing happens with Loft with Guides. With Loft we do some
"fudging" but when it comes down to it is not any better (turn on
display>curvature) than the quality of Boundary. In addition, many
users that are successful with Loft, don't use guide curves because
they've figured out that, like Johnny Depp says in Pirates " Well they
be more like guidelines than rules". Users know that you can not count
on the accuracy of Loft edges that were created with guides because
they don't follow them very well. Think of them more as influencers
for the direction between the profiles. This is one of Ed's main
points when he teaches about Loft, and he's correct. The reason that
Thomas and others (me included) are successful with Loft sometimes is
for this very reason: because of the influence profiles have over
guides. In some cases this works better. This is the key difference
between Loft and Boundary: Boundary's 1st and 2nd direction curves
have equal influence.

This is not true. The settings ARE remembered in the session of
SolidWorks. If you feel they need to be remembered as a doc or system
setting, then please submit an enhancement and I'll follow it up. It's
not difficult to change.

All the colors and combs

I can show you dozen of examples where Boundary outperforms Loft in
quality and speed. The fact of the matter is that we just didn't just
dream up a new feature, but we need to because of the limitations of
Loft with Guide curve. In fact we did an extensive benchmark in 2005,
2006 with hundreds of customer parts - solving there loft problems
with the Boundary feature.

I don't know how you can even compare Boundary and Loft to Fill. Don't
get me wrong, Fill is SolidWorks' "Crown jewel", but it can not
substitute or surpass what Loft or Boundary can do because of its
limited internal curve influence.

Matt, I'll have you talk to my wife - she'll tell you about the real
Mark - flaws and all

Seriously - yes I am confident in Boundary for what we created it for
- to overcome the bias influence of profiles verse Guides because
users wanted a "true" boundary feature (like ProE's boundary Blend or
ISDX) and they were trying to use Loft with Guides to do this.
Boundary uses the Gordon Surface algorithm which is more accurate and
more efficient (especially when using many curves in the network)

What we might be seeing when comparing Loft with Boundary, is that
Loft is more "forgiving" but the "dirty laundry" is still there -
especially when performing downstream features. The Boundary feature
is more exacting, and demands from the user, better sketch curves and
edges in order to attain a better quality surface. Perhaps this is an
issue we can look into further to see what we can do to make Boundary
more forgiving but we do run the risk of assuming what the user wants
as a result; a result that might not be the quality that they need.

Great topic and great discussion - I realize that there is still much
confusion about the differences between Loft, Boundary and Fill and
was the reason I dedicated a breakout session to it at our last SWW.

Regards

Mark

 

Thanks, guys. I'm a little less confused than I was before this discussion.
Sure wish I had been able to go to SWW!

Jerry Steiger
Tripod Data Systems
"take the garbage out, dear"

 

Great topic and great discussion - I realize that there is still much

Mark,

Any chance that sort of thing can make it's way into the documentation?
Should I be looking for it on the Customer Portal instead?

 

I have only played with this on someone elses pc since I'm on 05 but I
would much rather you applied quality to boundary than made it
compliant. The whole reason I wanted continuity improvements to edges
was that I didnt want to obsess about cutting and patching like Ed
does - sorry Ed - I see that as admireable but very unproductive.
I think they have complimentary roles.A tool to achieve your intent
with out being too fussed about conditions and another to join em up
well. As for the curvature combs...well a lost cause sadly

 

Mark,

What I am seeing is that in a corner, if the Boundary cannot match the
tangencies between the two different directions, it just gives up, and
gives you nothing except a friendly error message. The feature cannot be
created at all. What is most frustrating about this is that you could
trim a rectangular patch out of a single surface, and still run into the
error of matching tangencies between the two directions, which doesn't
make any sense geometrically. Rarely can I get the curvature option to
work in either direction. Sometimes there is an advantage to getting
something that is somewhat fudged in the corners rather than nothing at all.

Here's an example. http://www.dezignstuff.com/overflow/Part1.SLDPRT

This is a simple revolved surface, where a rectangular cut out is made
in the surface, which is then filled with the Boundary surface. If you
were setting up an easy slam dunk for this feature, what else could you
do? Turn on Zebra stripes and notice one side of the existing patch is
not even tangent. So edit the feature and set the first edge in the Dir
1 edges to Curvature. Notice the error that you get, "The guide or
profile curve's curvature at its end point(s) does not match the
curvature of the surface it touches." All that is selected here are
simple edges created from the trim. Interestingly, it still works, but
usually when I see this, the feature will not even work.

http://www.dezignstuff.com/overflow/Part2.SLDPRT

Look at the 3 configs in this second part. Loft can't even be created
with c2 on the profiles. That stinks. Boundary works, but with the error
shown above. The best looking patch is certainly the Fill.

Boundary gets compared to Fill because fill works in any situation where
Boundary works (except, as you mention below when internal control
curves are needed), and many situations where boundary doesn't work
(such as non-4-sided patches). Fill seems to "fake it" sometimes too.
Early in the 2007 release, you kept giving warning symbols on fills with
sharp corners. That doesn't happen any more. I assume that the
approximation it was giving the warning about hasn't changed, the symbol
has simply been taken away.

No, Mark, it is true. It doesn't remember the setting from one session
to the next. Because I don't generally make multiple Boundary features
in a row, I tend to do it at widely separated intervals, between which
SW has been turned off and restarted. So every time I use the Boundary,
I have to turn off the setting. Curvature combs with no caps. Freeform
doesn't do it that way does it? Loft doesn't do it that way either. Why
does Boundary automatically turn on combs? Let me turn them on if I want
to, but the default should be off.

Really, I'd like to see a few of those. Not that I don't believe that it
works, I know it does from the once or twice I've gotten really good
results from it. I just want to see what kinds of situations it works
well in, and what settings you used to get there. I at least try it
whenever I have a 4 sided gap to patch. I keep trying mainly on the
strength of your optimism, certainly not based on my own experience.

Yes, you're right. If I'm using Fill, it is in places where I don't need
to control internal curves. On the other hand sometimes you just need to
blend over a patch without any internal control curves. In these
situations, you can use either of the three types. I have often used
them all and compared the results. Loft is the most predictable, but
lacks GC conditions, as you mention. Fill is the easiest to use and
works in the most general cases. Boundary remains tempermental and
sometimes simply refuses to produce any results at all. I think I sent
in a tech support problem wrt boundary not working a couple of weeks ago.

I don't wanna know. I'm happy in my illusions. In my head, I imagine you
as a nice guy. Nothing from knowing you has contradicted that. I'm not
complaining about you, just a little disappointed with this feature. I
see what it is trying to do, and recognize that it could be useful, but
in practice, I just haven't seen many situations where it works. Provide
some of those examples for us all. You're trying to sell this feature.
I'll buy if I can see it work in situations I run into.

Right, I agree.

That is clear. So if it doesn't get what it wants, it just shuts down.
Also, I have to tell you that the only times I have crashed in the past
week have been when making adjustments in the Boundary feature. Of
course it's nothing I can spoon feed to tech support, but there is a
problem in there somewhere.

I don't know if "forgiving" is the right word. You can make the surfaces
in SW, and make them with a loft using c2, and then the quality of the
c2 condition across the boundary between faces is not good enough for
the Boundary surface, and it just fails. It is complaining about the
quality of the surfaces made by SW. Next time SW is footing the bill,
I'll take the time to track this down, because I see it regularly.

Also, I've never had good success with the handles in the Boundary
surface. Handles in loft are touchy enough, but in Boundary, they simply
don't work whenever I've tried them.

I agree. I want to see examples of where it has been applied
successfully. I think in general we agree about everything, except you
have several examples of where it works, and I have one or two, and
those were found only by trying all of the edge condition options and
combinations with the curve influence options. I've got to say that
those are both a major interface pain. There is no feature in SW that
requires so much clicking around.

If you would like to say more about the curve influence options, and
what they are really meant to do, I'd like to hear about that. To me, it
is just a toggle for two different solutions - I don't understand the
difference between the settings.

While we're at it, why don't you add a "merge result" option, like the
Fill surface?

 

well there you go matt, rendered butt naked again )

 

hmm well that shows boundary to be much tighter than fill doesn't it?
if I read that correctly boundary has less than <<0.01 deg ( very
small) departures with minor nips in opposite corners, and fill has
noticeable waves and departures up to 0.06 deg.
I remember Mark describing fill as being C1.5 previously...
Seems to me the results are what I would of expected but forgive me I
dont have 07 to test for myself

The butt naked was a joke - my humour you understand ;o)

 

Tangent Influence and To Next Curve seem to have the same effect. Do you
have any way of knowing before you try it how these settings are going
to affect the geometry (other than Random Button Pushing)? Using the
Curvature setting for the Dir2 edges should be what makes the connection
smooth. The curve influence settings in the direction1 have minimal
effect, and you can never tell until you finish the feature and run a
Deviation Analysis. This is part of the hassle of using this feature.
Deviation Analysis is not parametric, and has to be run after a knit, so
changing settings, rolling down, doing the analysis, it's kind of a
tedious process.

Thanks for showing that, but my confidence in the feature is little
improved if the only way to find the solution is to pick through all the
options one by one until you come up with something that works. I guess
I'm looking for something deterministic, predictable, and a little less
random.

 

John,


Thanks for the response. I guess I kind of agree with FlowerPot,
although I'd say it differently. How did you come by that solution? Were
you just trying random things? I would think the Curvature setting would
determine the results of the deviation analysis.

Matt

 

Wow Matt, I'm going to have to respond to your response to me over the
weekend, but great feedback and to the others that are in on this
thread. I want to look at your parts but I suspect that its the
surface trim that is causing the problem. Have you tried it in '08?
We are aware of a nasty result of surface trims, and deriving a
projected curve from it, and have been working to resolve it in '07
SPs and '08.

Yes, display analysis in Boundary does not transfer from session to
session but only in the session (as I stated). I would submit an
enhancement (and other here that feel passionately about it (and
qaulify it from a customer's perspective in the enhancement) to make
it a doc or sys option - Power in customer hits!

I'll get back to you this weekend Matt.

Perhaps I should put together an interactive webcast on the subject of
Boundary vs. Loft vs. Fill or do it with a select group of you. In
any case there is a lot that we could learn from this discussion.

Regards

Mark

 

Excellent discussion guys! Lots of good information. I haven't had
as much seat time lately with Boundary as I did towards the SW2007
beta and release. Overall my feelings on it are that I try to use it
first, then revert back to Loft if I cannot get the results I'm
looking for. I have had some pretty good success with Boundary in
general but I would prefer to use it most of the time since I feel
this will be the tool of the future. I need to crack the toolbox open
on it again in SW2008 and test some more. (I need a few extra hours
in my day it seems )

Mark - I think a webcast on this subject would be great. I would
certainly be there for it if my schedule allows!

Best Regards,

Ricky Jordan
http://www.rickyjordan.net

 

I am not sure this is a good discussion.Discussions here are rarely of
any real worth and interactive webcasts even further down the list let
alone exclusive ones.
I think it shows that people really dont have a good grasp of what the
tools are intended for and to this extent SW have failed to
communicate the differences or perhaps how the rules/purpose have
changed.
This is not so surprising however as the help notes have always been a
list of features rather than educational about function or their
mathematical basis.
Matts example is in my mind is not a good one anyway. If you have a
large sheet with a hole in it you are not going to use fill or
boundary to patch it. The matter of what happens between sheets is
more important. Pointing to very minor deviations in this example and
saying the feature doesnt work is a bit inappropriate. How <0.01 deg
looks/feels in reality I dont know but that seems pretty smooth to me
short of untrim.
I seem to remember suggesting the rules for lofting and filling could
vary depending on what sort of user you were.
Correct me if I am wrong but this is what you have done in a generally
accomodating way with a nod to ID people.
Loft has become more relaxed than previously and boundary has become
the conditional fit. With boundary you can search or refine for the
optimum fit rather than keep cutting away the bad bits and repatching.
The edges are a lot closer to continuity as a matter of course but
this means it is harder to satisfy.As a user you really shouldnt be
expecting it to create a wonder solution at the first try or in
'difficult' situations.If you want to preserve the model you already
have at that point then reverting to a more flexible loft may well be
the best way forward. my few cents..

 

"Or better yet produce a book that dealt only with lofts, boundry
surfaces, fiills, sweeps, etc and when one might be more effective
than another and make it available for a reasonable price."

What does it say that after 10 years the only good independent book on
SolidWorks that is available is Matt Lombard's SolidWorks Bible?
Lombard's book doesn't deal with advanced surfacing.

I believe the subject of advanced surfacing in SolidWorks is a
separate book unto itself and would need to be done by someone like Ed
Eaton.

The problem is that CADCAM companies protect their VAR network and
they see quality documentation as a loss and as something the hurts
the abilities of their VAR's to make money on training. The one
exception to this is McNeel's Jerry Hambly who has produced Rhino
Level 2 surface modeling training which is an exceptional piece of
work.

Jon Banquer
San Diego, CA

 

On the contrary, opportunities to learn from those who know more are

sorry my experience is that the 'discussions' (and webcasts) lack
depth partly to do with the time people have to spend interacting via
that medium and partly cos the silent majority are just that. I fondly
remember enlivening a struggling webcast with some spontaneous humour
cos a whole lot of folk just sat there and the provided info and
replies were way too general
if they are good for you thats fine.
you can try ask challenging questions here but you usually only get
well formed personal opinions thrown back and forth among a few
regulars
quite rare is it we get inside knowledge about something from SW
themselves (their policy apparently)
....no doubt this thread will soon be invaded by cliff and john anyway
and that will ruin anything useful..

agreed SW developers are not good at talking to users to say what they
are trying to achieve with a toolset
they just produce things or quietly change them and expect people to
not want to know the guts of whats happening with a loft etc
thank goodness for Ed Eaton sharing his solids and surfaces insights

yeah probably I said I had suggested before in one of my 'inspired'
thoughts that different users may need different rules for their
purposes..but why would you trim a hole and then boundary fill it as
Matt did? surely you are interested in constructing other things to do
with that hole and where the adjacent geometry matters.. dunno is a
loose 'sure to work' loft good enough for you or do you want it as
good as it gets after spending a while carefully fitting it up nicely?

hmmm, difficult is where you are trying to achieve too much in one hit
and not thinking laterally about how to get where you want to go
difficult is where you have boxed yourself in cos you didnt have a
plan of attack and only have a few options left to finish it off in
any way you can think of
difficult is where the situation just doesnt lend itself to the tools
as they are provided or in their present state

 

I have spent more time on this thread than I want to already but...

Well you are absolutely correct in this matter.
SW have strange policies when it comes to assisting their customers.
Strange because while they set out to make their software easy to use
they never want to talk meaningfully about it. Peculiar because they
tightly control their staff interaction and hide away anyone who might
actually be in the know.
Your role as a customer is to gratefully keep buying the half finished
product they made for you and be dumb and dependant.
I remember years ago I said much the same things as you are saying
now.
What happened, nothing...except Solid Professor came onto the
scene ...yup thats right someone else enterprising made something
useful about how to use the program, not SW... and now a few folks
have made generalised books too and good on em
The help notes remain incomplete and aimed at the level of 'this is
the horn button' and 'this is the wiper switch'.
Apparently the programmers are so good at their job that everything is
so intuitive you never need to think about anything you use let alone
be educated about its potential as the boffins conceived it. Its all
nicely colour coordinated and warm and fuzzy...and mostly brain
dead..well I suppose we need to give a hand up to Autocad
people...sorry guys
You can take some comfort by knowing all this stuff has been booted
around before.
I seem to remember the last event is what resulted in the webcast..
that duly hopped and croaked.
What happens when we get to a situation like this on the forum?
Well someone watching will give Mark a prod and he will pop up , make
a few conciliatory mumblings , talk about the features in the next
release , talk about a placid webcast he might do, everyone thanks him
and the matter dies ..blah ,blah...much the same complaint paralysing
banter you get when a major stuff up occurs..you know the routines I
am sure
I have poked eyes at SW in the past about all sorts of dead thinking
and been marginalised for it.
Really the more you prod at the walls the more concerned you become
that their are some self righteous slumbering people controlling the
company with very few real ideas of their own.
Keep asking though something might happen.

 

There is a new "Advanced Surface Modeling" manual that was just
release in May. I gave away a few copies at SWW. It is an excellent
example/tutorial-driven manual contributed heavily by Matt Lombard and
others. It is not for sale however, but offered as a 2 day course at
your local SW VAR.

Regards

Mark