after import from iges some meshes are double

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 From:  crydee
5216.1 
Hi Michael,

I have a strange problem. If I import some IGES files I get some meshes doubled. They are at the exact same position. If I import those files into antother program the whole model is fine. Do you have any idea?

Thanks in advance.
Ciao
crydee

EDITED: 28 Jun 2012 by CRYDEE

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 From:  Michael Gibson
5216.2 In reply to 5216.1 
Hi crydee, it might be some problem with the join process, if you model has any little tiny degenerate slivery surfaces in it those can tend to confuse the join process.

You can turn off the automatic Join process that happens on IGES import under Options > Import/Export > IGES options > "Join surfaces on import".

Does the doubling go away when you turn the joining off?

- Michael
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 From:  nycL45
5216.3 In reply to 5216.2 
I experienced much difficulties after exporting the ceiling detail pictured here that hopefully is related to how I set up the IGES and SAT exports from MOI for use in VectorWorks (VW). It could be VW and the way it handles IGES and SAT files.

After successfully importing the IGES and SAT files into VW, the objective is to convert them to 2D isometrics, which allows modifications. Also, the workflow is faster since rendering is no longer necessary. In VW, converting to 2D is done with Hidden Line Rendering and then selecting Convert Copy to Polygons.

The ceiling MOI file is 4.5 mb, the exported IGES and SAT files are 6.9 and 8.7, and after opening in VW, 4.3 and 6.2.

Now, when I convert to 2D, these files have a growth spurt - 396.5 mb and 495.6 mb! (Think "King Kong".)

Is there anything I can do on the MOI end to keep this from occurring? (VW, right?)

Thanks.
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 From:  Michael Gibson
5216.4 In reply to 5216.3 
Hi Leonard, the processing that does the conversion to 2D and causes the growth spurt is happening inside of VectorWorks, is that correct?

If so then I don't know of anything you could do on the MoI side to prevent that, maybe there are some settings for the VectorWorks conversion mechanism that you could loosen to prevent excessively dense geometry from being created by VectorWorks. MoI itself is not able to influence settings that are specific to VectorWorks like that though.

You probably need to investigate what in particular is taking up most of the file size - is it that there is a tremendous number of curves? Things fragmented into little bitty pieces? Each curve having zillions of points in it? Or ? ... Once you know why it is so large that may suggest some course of action.

- Michael
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 From:  nycL45
5216.5 In reply to 5216.4 
Hi Michael! Thanks for responding.

>Things fragmented into little bitty pieces? Each curve having zillions of points in it?

I believe that is it. The attached images are of the hanger rod only and the following are the file sizes:

3dm file = 434 kb
igs file = 45 kb
igs > vw = 139 kb
vw 3d > vw 2D = 20.7 mb
vw 2D (deleted unnecessary polys with line weight of 0) = 127 kb

Images: 1. Hanger rod converted to 2D, all objects selected. 2. Only polygons with line wt. = 0 selected. 3. Polygons in image 2. deleted; remaining lines selected.

I am pushing on this because 1) MOI is faster than VW and I want to use it, and 2) hopefully someone knows of a work around. Otherwise, MOI is of limited value for architectural construction documents.

Leonard
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 From:  Michael Gibson
5216.6 In reply to 5216.5 
Hi Leonard, is it possible for you to send me the 3DM model file with that one rod piece in it that you're showing there?

I can take a look at it to see if there is anything in the model itself that might be able to be simplified.

But it really looks like some mechanism in VW that needs to be tuned up - generating 107187 polygons for that one piece definitely seems excessive. Also why is it generating polygons in addition to lines, is it trying to do some kind of 2D shaded fill effect with 2D polygons? Maybe there is a way for you to switch that part of the 2D generation off so that you only get the lines?

Is VectorWorks not very oriented on working with actual curved model data directly? I mean does it take your IGES import and then immediately dice it up into a bunch of triangles right when you do the import? Maybe that's the fundamental issue.

What happens if you just transfer a single sphere from MoI to VW using IGES format, does it generate some complex 2D drawing from that as well? That would probably be a good test to try. If that generates a complex 2D result then it's likely that the drawing generation mechanism in VW just does not deal very well with curved objects in general, and I don't see what could be done in MoI to solve that problem.

- Michael
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 From:  Michael Gibson
5216.7 In reply to 5216.5 
Hi Leonard, also if MoI to VectorWorks to 2D drawing is not going to work for you due to VW's behavior when using curved surfaces, you might instead try ViaCAD 2D - it can read in 3D CAD files and generate 2D drawings, the 2D edition only costs $40:

http://www.punchcad.com/p-7-viacad-2d-v7.aspx

- Michael
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 From:  nycL45
5216.8 In reply to 5216.6 
Hi Michael,

>is it possible for you to send me the 3DM model file with that one rod piece in it that you're showing there?

Attached.

>...generating 107187 polygons for that one piece definitely seems excessive.

As you noted earlier, it is the curved surfaces. Boxy shapes and 3D forms are more efficient.

>Also why is it generating polygons in addition to lines, is it trying to do some kind of 2D shaded fill effect >with 2D polygons? Maybe there is a way for you to switch that part of the 2D generation off so that you >only >get the lines?

>I mean does it take your IGES import and then immediately dice it up into a bunch of triangles right when >you do the import?

The IGES file import is a full 3D model in VW and with boxy forms, triangles. VW 3D to 2D conversion offers fill (hidden line rendering) or no fill, aka wireframe. Wireframe = manual clean up while the other is fast and there is a manipulatable isometric with the bare minimum of lines as the product.

As you predicted, a sphere from MOI via IGES generates a complex 2D result using the hidden line rendering method vs. the wire frame (pics attached). So, yes, how the IGES curved surfaces are worked in VW is key.

I was hoping I had missed a MOI/IGES on-off switch, dial, slider, radio button or whatchamacallit that would help or that some bright spark would have a bypass. Alas, it is not to be.

Thanks,

Leonard

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 From:  nycL45
5216.9 In reply to 5216.7 
I had a quick look at ViaCad just now and will need to check it out a bit more.

Leonard
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 From:  Michael Gibson
5216.10 In reply to 5216.8 
Hi Leonard, thanks for attaching that rod model. I took a look at it closely and I do not see anything out of whack or unusual about it in any way, so I don't think there is anything you could do on the MoI side to change what you are seeing.

Since you also see that excessive density with just a regular sphere as well, as far as I can tell it's a problem that VectorWorks has with curved surfaces in general. You would need to contact them about improving that or modifying that behavior. Maybe there are some settings available that would allow you to adjust the density downwards somewhat - if those exist they are going to be settings on the VectorWorks side though that controls the behavior of their drawing generation mechanism. Since it's a mechanism in VectorWorks that needs adjusting there won't be any settings on the MoI side that you would use to affect that.

- Michael
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 From:  nycL45
5216.11 In reply to 5216.10 
Hi Michael, thanks for your help and I will check in with VW. If there is any news, I'll post here for VectorWorks users.

One final note, the problem might be the IGES>VW AND SAT>VW conversion. The images below are a VW-generated sphere (same 6" rad. as previous) and it results in about 85% fewer objects and 70% fewer lines in the final object.

Thanks for a great product.

Leonard
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 From:  Michael Gibson
5216.12 In reply to 5216.11 
Hi Leonard, check what kind of entity is created for the VW-generated sphere, does it really construct a truly curved NURBS sphere or does it make a set of polygons arranged in the general shape of a sphere? I would think it's likely the latter and that is probably the key difference.

Does VectorWorks also import polygon mesh data? If so maybe you should try exporting out from MoI as a polygon mesh object type (like .obj or .3ds formats for example) rather than as NURBS data, maybe that will tame things down.

- Michael
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 From:  crydee
5216.13 In reply to 5216.2 
Hi michael,

again you are my hero. we get some unfinished cad-files from our customers to build virtual prototypes. It's a borring job to prepare and tesselate those files. I asked you a long time ago to colorize each meshgroup. You gave me a solution and with this help we can really quick import tose models into our software. The only bad thing are this double meshes. After i deactivated the "join surfaces" in your import option everything is fine.You saved us a lot of time and trouble.THANKS THANKS THANKs:)

Have an nice day.
Crydee

EDITED: 2 Jul 2012 by CRYDEE

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 From:  nycL45
5216.14 In reply to 5216.12 
Hi Michael, we have, I believe, a happy ending.

Following up on your last post I tried VW Preferences>3D>3D Conversion Res set to medium (was "very high") and it worked! I had no idea, and no mention in the manual, that it applied to IGES and SAT imports.

The ceiling isometric was a good test for MOI working with VW, ergo clear sailing from here.

Thanks for hanging in there with me on this.

Leonard
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 From:  Michael Gibson
5216.15 In reply to 5216.14 
Hi Leonard, that's great news that you found a setting in VectorWorks to reduce the excessive density! Thanks for reporting that back here as well, that can help other people who might be using MoI and VectorWorks in combination in the future as well.

- Michael
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