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DWG with multiparts being split by reader in FME


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Hi everyone,

 

I have a dwg with autocad blocks which has several layers of polygons, polylines and annotation. I have a workspace to extract and convert these to shapefiles.

 

The problem I have is that multipart polygons and polylines are being split by the FME reader. When opened with ArcMap or Autodesk TrueView, the multiparts appear correctly. I have tried to play around with the parameters of the dwg reader (entity option/advanced options...but everything I have tried so far has not worked and some of the settings read far fewer components than needed).

 

Anyone have any experience with this?

 

Thanks in advance! :)

Best answer by daveatsafe

Hi @kewhew​,

When the DWG reader explodes blocks, it outputs a separate feature for each component of the block, but maintains the relationship of the components using the format attribute autocad_block_number. You can expose this attribute on the source feature types, then use an Aggregator to group the components by autocad_block_number to create multiparts for each block instance.

FME 2023 introduced the option to read the blocks as geometry instances, which will automatically create a multipart from each block, and best reflects the actual structure of the block within AutoCAD. If you are using FME 2023, I would recommend enabling this option.

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daveatsafe
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  • Safer
  • Best Answer
  • October 27, 2023

Hi @kewhew​,

When the DWG reader explodes blocks, it outputs a separate feature for each component of the block, but maintains the relationship of the components using the format attribute autocad_block_number. You can expose this attribute on the source feature types, then use an Aggregator to group the components by autocad_block_number to create multiparts for each block instance.

FME 2023 introduced the option to read the blocks as geometry instances, which will automatically create a multipart from each block, and best reflects the actual structure of the block within AutoCAD. If you are using FME 2023, I would recommend enabling this option.


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  • October 30, 2023
daveatsafe wrote:

Hi @kewhew​,

When the DWG reader explodes blocks, it outputs a separate feature for each component of the block, but maintains the relationship of the components using the format attribute autocad_block_number. You can expose this attribute on the source feature types, then use an Aggregator to group the components by autocad_block_number to create multiparts for each block instance.

FME 2023 introduced the option to read the blocks as geometry instances, which will automatically create a multipart from each block, and best reflects the actual structure of the block within AutoCAD. If you are using FME 2023, I would recommend enabling this option.

Hi @daveatsafe​ thanks a lot for your response. I tested both options (just installed 2023 to try) and they work great! :)


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