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Large IGS and STP files in SW 2005

Large IGS and STP files in SW 2005

Large IGS and STP files in SW 2005

(OP)
I recently received a giant (580 MB) file from a client in IGS format.  I tried opening in in SW 2005 and it crashed my machine.  My client then trimmed down the model (removed data I didn't need) and sent it in both IGS (240 MB) and STP (145 MB) format.  I tried opening the smaller STP file, and got farther than before, but after about 20-30 minutes, the system is just frozen.

My system is as follows:
P4 3.2 Ghz
2 GB memory
Quadro FX 500 video
Win XP Pro SP2

Is my system just not able to handle files of this size? I have never had to deal with files this large before, so I am unsure if my hardware is just lacking, or if the issue may be elsewhere.  Anyone have an idea of what specs my system would need in order to handle files this size?

Thanks!

RE: Large IGS and STP files in SW 2005

What MCAD package is the data native to?  It could be that the data contains a lot of surfaces or complex geometry.

Here is some information from an article I got from the web

Tolerance Strategies:
If the gaps between edges and faces become too large, solid-modeling programs can become confused about the boundaries of the model. The system can no longer distinguish the inside of a part from the universe around it. In such cases, the user might receive a message that the model is "corrupted." Consequently, all systems employ a strategy for computing the maximum allowable gap, or "tolerance zone," between an edge and the two faces it bounds. Unfortunately, different systems employ different strategies for computing this tolerance.
 
Pro/Engineer employs a variable tolerance model. The maximum gap is a fraction of the total model size. So for large models, such as jet engines, Pro/E allows larger gaps, while for small models, such as watch parts, only small gaps are permitted. The relative tolerance model is a clever one, and it enables Pro/E to run fast. Unfortunately, no other major CAD firms have adopted this strategy.
 
Most systems, including CATIA version four, Computervision's CADDS, and Spatial Technology's ACIS (employed by AutoCAD, Ashlar Vellum, IronCAD, SolidDesigner, and TurboCAD), employ a fixed tolerance model. The size of all gaps in all models is limited to the same default value. Most systems enable users to change this default value but the vendors strongly discourage such changes with scary disclaimers of what might happen to the CAD program's behavior.
 
The Parasolid kernel employed by Unigraphics, SolidWorks, Solid Edge, and Microstation employs a concept called "tolerant modeling." The tolerance is fixed, but larger gaps may be permitted on a face-by-face basis.
 
The difference in tolerance strategies causes problems when translating geometry from one system to another.

Models coming from Pro/Engineer or Unigraphics may have gaps that aren't acceptable to CATIA or SolidDesigner. The reverse is also true: Models from fixed tolerance systems may be unacceptable to Pro/E or UG if they contain gaps that are too large.

Low Accuracy:
Designers creating CAD models do not generally notice gaps between adjacent faces or between faces and their associated edge curves that exceed the allowable tolerance of their CAD programs. But such gaps can cause translations to fail and can stall NC, rapid prototyping, and finite-element applications.
 
There are a couple of ways that large gaps can creep into models. Because of its relative-tolerance strategy, Pro/Engineer can leave large gaps between large faces. ITI found one instance -- in an aircraft engine housing -- where a gap exceeded one millimeter.

Solid-modeling programs with fixed tolerances generally won't be able to sew up models with such large gaps. In these cases, translations simply fail, and it is up to the Pro/E user to tighten down the tolerance, regenerate the model, and try again.
 
Tolerant systems, such as those based on Parasolid, will sew models with large gaps. Large gaps also can be introduced into Parasolid models by importing surfaces. Surface-modeling programs -- such as Alias Studio or Pro/Designer, don't care about gaps between surfaces. Once incorporated into the solid, these large gaps can be passed through to STEP or IGES models or they can stall FEA, NC, and rapid prototyping programs. Or they can cause translations to programs such as AutoCAD or CATIA to fail.

Users of hybrid modeling systems can reduce accuracy errors by closing gaps between surfaces before importing them into solid-modeling programs. Most industrial designers don't have the patience for this type of work. Managers instead should hire cad-savvy technicians to check models before introducing them to engineering systems.

Best Regards,

Heckler
Sr. Mechanical Engineer
SW2005 SP 5.0 & Pro/E 2001
Dell Precision 370
P4 3.6 GHz, 1GB RAM
XP Pro SP2.0
NVIDIA Quadro FX 1400
      o
  _`\(,_
(_)/ (_)

Never argue with an idiot. They'll bring you down to their level and beat you with experience every time.

RE: Large IGS and STP files in SW 2005

Do you have the /3GB switch enabled? If not it is the first thing you should try. It does not cost anything but is often very effective.

If you can also add more RAM (borrowed from another machine?) that will also help greatly.

cheers
Helpful SW websites FAQ559-520
How to find answers ... FAQ559-1091

RE: Large IGS and STP files in SW 2005

(OP)
Thanks Heckler! I activated the /3gb switch, but it still didn't work.  I know the client is using ProE, so the explaination you give seems to make the most sense.

RE: Large IGS and STP files in SW 2005

Did you get any further using the /3GB switch?
I'm not sure if you have to, but did you reboot after applying the switch.

BTW, SolidWorks can open native ProE files. I don't know how well SW05 translates, but SW06 did a good job with the files I imported.

Quote (SW Help):

Importing Pro/ENGINEER Files into SolidWorks

The Pro/ENGINEER translator imports Pro/ENGINEER part or assembly files as SolidWorks part or assembly documents. The attributes, features, sketches, and dimensions of the Pro/ENGINEER part are imported. If all of the features in the file are not supported, you can choose to import the file as either a solid body or a surface model. The Pro/ENGINEER translator supports import of free curves, wireframes, and surface data.

When importing an assembly, you can control how to import individual components. Sub-assemblies are supported as well.

You can import Pro/ENGINEER surface-trim and surface-extend features into SolidWorks. These features are read in from the Pro/ENGINEER file and mapped to SolidWorks.

Some known limitations are as follows:

Version Information - Versions 17 through 2001 of Pro/ENGINEER and Wildfire versions 1 and 2 are supported.

Assembly features are not supported.

cheers
Helpful SW websites FAQ559-520
How to find answers ... FAQ559-1091

RE: Large IGS and STP files in SW 2005

I've imported a lot of Pro/e files into SWx via STeP and feature works.  One thing to keep in mind is not all features cross over between the two systems.  For example, Pro/e has a variable section sweep and SWx doesn't so those features will not translate.  That's the same reason why parametric modeling will never be downward compatible...okay A-CAD users stop submitting enhancement requests. lol

Here is some data that you might want to check with the originators of the pro/e data.  Best of luck to you.


ENABLE_ABSOLUTE_ACCURACY - Yes

ACCURACY_LOWER_BOUND - value (between 1.0e-6 and 1.0e-4).


http://www.technicom.com/newsite/pdf_files/UVDM_paper.pdf

http://www.proesite.com/accuracy.htm

Typically, a default relative accuracy of 0.0012 allows geometry to be calculated with a reasonable amount of computation and within a reasonable amount of time. Sometimes, however, specific model geometry may require that geometry calculations be sensitive to fine features or complex geometric shapes. Modification of accuracy for a model with this higher "level of detail" may be used as a last resort to assist Pro/ENGINEER in solving the model geometry.

Best Regards,

Heckler
Sr. Mechanical Engineer
SW2005 SP 5.0 & Pro/E 2001
Dell Precision 370
P4 3.6 GHz, 1GB RAM
XP Pro SP2.0
NVIDIA Quadro FX 1400
      o
  _`\(,_
(_)/ (_)

Never argue with an idiot. They'll bring you down to their level and beat you with experience every time.

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