Import 3d Iges data

Solidworks 2004 Sp4.1

Is there any way I can import a clients 3d Iges geometry model consisting of
3d and 2d curves and datum planes into Solidworks? There isn't any solid or
surface data and Solidworks fails consistantly to import the planes.

Anyone have any workarounds or suggestions please?

 

What package is the iges coming from?

 

Phil under the Iges import command hit options and make sure that
freepoints and curves is checked.

 

Phil,

Yuk... Is it a Boeing file ?

I don't think SW supports IGES "plane" entities. The last V4 IGES I worked
with was a set of air load ribs for a 757, there were five of them. The
files were horrible, containing only 3D curves (most of them construction),
a bunch of reference planes, CMM points, and a couple of untrimmed surfaces
that defined the leading edge of the wing. I was able to bring all this crap
into SW by turning on the appropriate options in the "options" area of the
"open IGES" dialog.

What I ended up with was a hairball 3D sketch with all the curves and points
in it, and the untrimmed surfaces. No referance planes. To me, this was
totally unmanageable in SW. I ended up reconstructing the first part in
Mastercam. It supports levels and planes, (you needed the planes to measure
the part). The solid construction methods in MC are similar to Catia
(primitive), so I was able to use most of the construction geometry. It
still took quit a while to do, and the client wasn't very happy about the
added labor (neither was I)

For the last four pieces, we sent the native files to a service bureau. For
about $200.00 bucks apiece, we got back usable parasolid files. This was
about 1/4 the cost of me reconstucting each part, and allot less hassle.
From here, I was able to design the CNC tooling, and program the part pretty
easily, The plane data didn't translate, or I forgot to mention that I
wanted it. I was able to merge the parasolid with the original IGES data, in
Mastercam to get a proper layout for measuring.


Regards

Mark

 

Phil,

I think you'll find that the native Catia files already contain a solids.
The company I was consulting for was a big ass tier 1 vendor in Azusa CA.
They had five axis gantry mills that you could fit an 18 wheeler onto. They
did wing spars and bulkheads and such. They farmed out all the small stuff.

I had no trouble getting the native files from them. They all know the Catia
IGES is garbage, and most would rather have good parts the first time. They
won't think any less of you for asking for it. If you can get these you're
halfway there. Like I said, I didn't specifically ask for the planes when I
sent the files to Theorem. They may be able to translate them

Do you have access to another system besides SW ? As good as it is in some
areas, it's grossly deficient for working with big time aerospace stuff.
Most of these companies use either CADDS, Catia V4, or UG. Of the three UG
is the only one that outputs decent data, but it still uses the old style
data structures.

Regards

Mark

 

SW's IGES import engine does not process planes.

3D wireframe should not be a problem. Under the import options
(button on the file open menu) you can choose to import curves as
sketches or as SW import curve features.

 

Old trick that should still work is have the customer create a small planar
surface at each work plane then this will allow you to define your own work
plane in sw very easily.
Hope this
helps Rocko

 

Phil,

I just thought I'd add, that it's not so much that SW is a solids only
modeler. It's not anymore, although surfaces are a pain in the ass. I don't
know of any CAD system that can read Catia 4 IGES sucessfully. The main
reason is,,,there's nothing there to read. STEP from ver 4 is no better. The
internal accuracy prevents a valid solid file from being generated.

It mostly has to do with how the data is represented mathematically, and
structurally, inside Catia 4. Catia 4 uses bezier mathematics to represent
algorithmic curves and surfaces. It also seems to have a bizarre way of
representing analytics. Solidworks, and every other major CAD system
including Catia 5, uses NURBS math. The internal accuracy is also very
loose.

In order to write an IGES file for a NURBS based system. The bezier stuff
has to be converted to the equivalent NURBS data (preprocessed) before the
IGES file can be generated. In the case of algorithmics, this results in an
approximation of an approximation. This usually (at least with their
translator) causes data loss or corrupted data. It can be done though. There
are several third party translators available. Typically they use
sophisticated code to "heal" the data as part of the translation process. If
you have to work with allot of this stuff, a good translator will pay for
itself pretty quick.

Back in the early and mid 90's Dassault's attitude was, "if you want to work
with Catia data, you should have Catia". Thus, they never put much effort
into developing a good translator.

Regards


Mark

 

We are preparing to switch from AutoCAD to Solidworks. We have an
extensive library of objects that modeled using polyface meshes (what
many nowdays call wireframe...but I think that is a misuse of the
word). On version 3, I attempted to import objects both as a DXF and
an IGES file with the planes as surfaces. I never was able to get
anything usable.

There is a vast library of Mesh objects available on the internet,
and I would love to be able to use them.

Anyone know the status of this issue with version 5?

Joe Dunfee

 

Smiley,

Version 5 of what ??? There is no version five of Solidworks. Do you mean
Solid Edge ??

Solidworks can import mesh files, but they're not very useful. I think there
is an add in that will read 3D DXF meshes directly.

In a solid modeler you have a display list "mesh" overlaying a
mathematically exact model. This mesh is generated, shaded, and smoothed by
OpenGL.

In a mesh based system, the geometry "is" the display list. When this type
of geometry is read into SW you end up with a very rough faceted
approximtion of the shape. Since there is no underlying exact shape there's
no way to make them look smooth. They're also very burdensome on the system

NURBS models, from systems like Maya, work great. Unfortunately, they're not
as common.

Regards

Mark

 

You might search Rhino's site for "smurf". It might help with simpler
geometric forms (never tried it myself). For more complex shapes big bucks
in software (GeoMagic?) and some additional work is required if what I've
read is accurate.

 

Sorry for the delayed response, I've been out of town. I have no
idea where my "version 5" reference came from... typo? It was on
version 2003 that we attempted to import a simple 1" square cube which
was created as polyface mesh object in AutoCAD. To describe the
object a bit more, if you explode the object in AutoCAD, it is made of
3D faces.

If I recall correctly, the only option for me at the time was to
export the mesh object from AutoCAD as a IGES file, then import that
to SW. However, the results were not a cube, but rather 6 separate
surfaces in SW. It seemed that in the translation the surfaces of the
cube would not end up as perfectly parallel because of rounding
errors.

I just researched some of the old messages on the subject. Polytrans
is one option, and we have an older version... perhaps the new version
is better at it now. One vendor posted back in 2003, saying,
"Capvidia is developing a new add-in for SolidWorks to create
parametric models from STL/Mesh or point clouds. We hope to release
it this fall." Perhaps FeatureWorks is the current equivalent to this
software. But I am not in need of parametrics... just a dumb object.

Other people posting at that time were also having difficulty
getting usable meshes to translate into Solidworks. It seems the
process has always been there, but may not work as smoothly as we
would like. I guess all that is left to do is to try it on the new
version and hope the process has improved.

Joe Dunfee

 

Joe,

That's because polymesh objects are very imprecise "approximations".
Solidworks, and all the others, are "exact" modelers.

I'm very skeptical about the usefulness of data produced in such a way. Like
I said in my previous post, "there is no underlying mathematical data
describing the shape". Any system capable of doing that would require allot
of intervention from the user. The relative accuracy of the objects would be
very poor at best. Of course, if you only need objects for display, this
shouldn't matter.

Nope, Featureworks is designed to work with real surface data (mostly
analytic).

Not in 2004, non planar features still display as faceted, even when
imported as a graphics object.

There seems to be alot of folks that would like to use polymesh objects for
things like rendered scenes and such. I can't blame them, there's an awfull
lot of available models out there. There really is no reason why Solidworks
"can't" allow you to import a mesh as a graphics object/objects, and apply
"smoothing" functions to it. This is what polymesh modelers do. The mesh
isn't really smooth, it's all done with the shading functions. Ironcad has
been able to do this at least from version 2.

However, attempting to use polymesh files as a basis for a manufactured
design is not only a waste of time, it's just plain dumb.

Regards

Mark

 

It all depends on what you are depicting and your usage. In my
case, I've have instances where I want a representation of a
theatrical spotlight to get a feel for how much space it has to move
around and just to show that the object is there. I've also inserted
meshes of things like people, air conditioning condensers, and
forklifts into AutoCAD drawings for similar reasons.

A mesh is also capable of precisely representing a faceted object.
The square tubing (and things like U-Channel) I mentioned at an
earlier post can be well represented, even if the 1/32" radius on the
corner is not depicted. This is a case where AutoCAD's difficulty in
editing ACIS solids tends to force users to use meshes for weldments
using these kinds of structural steel. Such drawings seem to be
forever quarantined from the solid modelers which can't import them.

Sorry to be argumentative (I do value your replies), but for me,
importing mesh objects is something I would have a lot of use for.

Joe Dunfee

 

I agree, "display objects" being the keyword here.

"Precise faceted object" is an oxymoron. Solidworks uses double precision 64
bit math, and very advanced mathematics to calculate surfaces and
boundaries. That's precise.

Like I said, Ironcad has been able to import and display smooth mesh objects
forever. Solidworks "could" do it if they wanted to. Being able edit them
would be a bit of a stretch.

No problem,, but I think your kinda stuck in the "Autocad does it like this"
mode. SW doesn't do "anything" like Autocad, and never will. 3D models are
not "drawings".

You'll need to lose the Autocad mindset if you ever want to be productive
(and happy) using modern tools.


Regards

Mark