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steveFitz

224 post(s)
#13-Aug-18 12:36

I've noticed with both M8 and 9 that imported dwgs occasionally have strange 'artifacts' being odd distortions of a few objects in a drawing.

Here is an extreme case from a drawing I've been sent to work with. While there are a few artifacts in the drawing, these circles I've isolated out demonstrate the craziest looking - kind of Picassoesque really.

I've tried saving back to different versions etc. but still get variations on the same distortions.

Any ideas anyone?

Attachments:
CAD_Circles_R2013.dwg

Dimitri

5,083 post(s)
#13-Aug-18 15:44

That's an interesting file.

As noted in the DWG, AutoDesk topic, 2013 DWG format is not supported. Only 2000 format is supported. Use Autodesk's free DWG TrueView package to convert to 2000 format.

Top priority is reading authentic DWG files, that is, those which are created by Autodesk products or licensed TrueView applications.

Onward...

To dig deeper, I assumed from the file name it is in 2013 format, not 2000 DWG format. I imported it into DWG TrueView, which complained the file was not created by an Autodesk or Autodesk-licensed product.

But DWG TrueView did import it OK, displayed it seemingly OK and converted it into 2000 format.

Artifacts show up, as you describe, in LibreCAD, as well as in 9, both with the original file and as converted to 2000 format. GDAL fails to import it at all, either in the original version or as a 2000 format conversion.

Some questions:

1. What package created this file?

2. What is it supposed to be?

I'm most interested in your report of strange artifacts occasionally when you import DWG in GIS work:

3. Does that ever happen in 9 when you import from 2000 format using 9.0.168? Do you have an example?

adamw


8,216 post(s)
#13-Aug-18 16:39

We support more modern variants of DWG since 9.0.168, although the support is not exhaustive: we support a lot of what the format allows, but not everything.

Regarding the file, we will look into what it contains.

steveFitz

224 post(s)
#14-Aug-18 10:53

I cut the dwg sample from the original file using free DraftSight 2018 which seems easier, quicker and more useful than TruView (well it can edit too!).

Following Dimitri's example I converted the original file to R2000 using TruView and it didn't complain of it not being AutoDesk. Importing the R2000 file into M9 9.0.168 appeared similar to importing the original file. I can't share the original file but am happy to cut samples (and move their location) to demonstrate artifacts, etc.

I checked the original file and it is version 2010. I expect the authors used ACAD to draw it as it comes from a big Australian construction company that probably has hundreds of ACAD licenses.

Some questions:

1. What package created this file?

2. What is it supposed to be?

I'm most interested in your report of strange artifacts occasionally when you import DWG in GIS work:

3. Does that ever happen in 9 when you import from 2000 format using 9.0.168? Do you have an example?

1. I suspect ACAD 2010 (unlikely to ever find out even if I did inquire).

2. I've got no idea. It looks like a booster part for a Falcon 9 Heavy but I suspect it is a symbol for a service in a proposed street construction.

3. Yes. Well, actually I have only ever imported into 9.0.168 once (this example) but it does occur in M8 and edge versions of 9 I have tried in the past. Quite often with the larger estate subdivision drawings there are a few large curly things that appear on import that I just delete or turn off (I only really need the lots, street features and trees). I've attached another example from the same drawing (a flow arrow) and a screen shot of the original dwg (saved as 2000) and imported into M9 with Bing Streets behind it to show the extent of the artifact.

I'm happy to post examples of future artifacts I come across as I find them if it will help.

Attachments:
Arrow_R2000.dwg
Artefact1.PNG

steveFitz

224 post(s)
#14-Aug-18 11:18

Interestingly the Arrow_R2000.dwg appears to import into M8 fine but not into M9.

Dimitri

5,083 post(s)
#14-Aug-18 13:13

Best to send such examples as bug reports. That guarantees they get handled quickly. Posting them here is taking the chance they don't get noticed, and if they are noticed, might miss a build cycle or two.

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