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Hi everyone,

I am very new to FME having recently downloaded a free trial, so please bear with me.

I work on a civil engineering project and the majority of our design data (AutoCAD 2013 DWG) is on the OSGB36 grid (Ordnance Survey Great Britain).

To transform it to our local site grid I applied a series of modifiers (scaler, rotater, offsetter) then set a writer to output as DWG.

We tested it with the largest of our model files and found that the output file was around 800Mb in size whereas the input file was only 200Mb. Does anyone have any idea why this could be happening?

I am an Engineering Surveyor so I am rather unfamiliar with AutoCAD beyond simple commands & geometry etc, so the settings in the reader / writer don't mean much to me either!

Thanks in advance for any help or advice.

John R

Hi @johnrobson - yes there are a lot of settings in the DWG writer, and it can be hard to know what they do. I looked up a similar case and found these suggestions:

1) By default, FME will expand the blocks in your AutoCAD file into their
component parts. To disable this, open the reader Parameters in the
Navigator pane of Workbench and set Expand Blocks into Entities to No.
To write out the actual blocks to another DWG file, you will need a
template file for the writer that already has those blocks defined. The
easiest method is to use the source file. Open the writer Parameters in
the Navigator pane of Workbench and set the Template file location to
the the source DWG file. Only the header of the template file is used -
not any of the actual data.

2) There is another setting for Store Bulge Info, that defaults to No. On this
setting, bulged linestrings are stroked, which can also increase the
file size. Please try setting this to Yes and see if the file size
drops.

3) Also change the settings Read Visible Attributes as Text
and Explode MText Entities to No

I can't guarantee these will be the solution, but they are what I would start with first of all.

Hi @johnrobson - yes there are a lot of settings in the DWG writer, and it can be hard to know what they do. I looked up a similar case and found these suggestions:

1) By default, FME will expand the blocks in your AutoCAD file into their
component parts. To disable this, open the reader Parameters in the
Navigator pane of Workbench and set Expand Blocks into Entities to No.
To write out the actual blocks to another DWG file, you will need a
template file for the writer that already has those blocks defined. The
easiest method is to use the source file. Open the writer Parameters in
the Navigator pane of Workbench and set the Template file location to
the the source DWG file. Only the header of the template file is used -
not any of the actual data.

2) There is another setting for Store Bulge Info, that defaults to No. On this
setting, bulged linestrings are stroked, which can also increase the
file size. Please try setting this to Yes and see if the file size
drops.

3) Also change the settings Read Visible Attributes as Text
and Explode MText Entities to No

I can't guarantee these will be the solution, but they are what I would start with first of all.

Curious what the result will be!

 

 

Thanks @Mark2AtSafe - we tried your suggestions and the resulting output is now only around 30Mb larger than the input file, which we can live with.

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