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AutoCAD Frequently Asked Questions

Based on the queries I frequently encounter, I have created an AutoCAD® Frequently Asked Questions page.

  1. What is the best way to integrate external consultants?drawings?

  2. Why won’t my xrefs bind and how can I bind problem xrefs?

  3. Which bind method should I use ?Bind or Insert?

  4. Which PDF driver should I use with AutoCAD?

  5. The wipeouts in my PDFs don’t print properly

  6. I cannot create a PDF from a drawing that contains Gradient Hatch


1. What is the best way to integrate external consultants?drawings?

Using data that has been sent to you from external sources can cause problems to the smooth running of your drawings. Consultants may use different CAD systems or different versions of the same software. They most likely have different CAD standards and may use their own custom elements such as fonts or line types, all of which can cause stability issues with your files.

Just because a file has a DWG extension it doesn’t necessarily mean it is safe and problem free to use. Different CAD applications have the ability to write out from their native format to DWG but these files can be riddled with problems. For example, a client received a drawing from a consultant that only contained several polylines, however, the drawing was nearly 800kb in size which is about ten times larger than if it had been created by AutoCAD.

If possible, at the front end of the project, attempt to meet with all consultants that may need to exchange data. Swap CAD manuals, discuss each other’s CAD standards and agree on a simple set of rules that you all abide by which is for the benefit of everyone’s workflow. If you regularly have to clean up a file from one particular consultant that will involve a lot of repetitive work, it may be worth investing some time in writing script routines that will automate tasks. It is also a good idea to use the Layer Translator tool for repetitive layer clean up.


To help reduce problems follow these guidelines:-

  • If you have to use the line data from a consultant's drawing never insert straight into your file. Always use copy and paste to extract the required data from the drawing into a clean template file from your company, then use the purge and audit commands to further clean the file. Once that has been done, then copy and paste the data into your drawing. Use the intermediate file as a ‘quarantine?area.
  • If the consultant's data is for reference purposes only, for example, it is just forming a back drop to your drawing and will not be edited such as a structural engineer’s column layout in an architectural plan, avoid inserting the drawn data from the external source straight into your AutoCAD file and instead xref it. This will isolate any corrupted data and it should be easier to pin-point any problems. I would suggest opening the consultant’s drawing and using copy and paste to take only the information you require and paste into a clean template file. Use the purge and audit commands to further clean the file and then xref as required.

  • If the external file is looking for custom elements such as fonts or line types when opening, speak to the person who sent you the file and ask them to send you the missing items. If that’s not possible try copying and renaming the same type AutoCAD files to match the custom ones and place them in the AutoCAD search path which should suppress dialogue boxes when opening.

  • Proxy Graphics contained in external drawings can also cause problems. These are drawing elements created by AutoCAD vertical products such as ADT or Architecture, MEP, etc. and cannot necessarily be handled by AutoCAD unless the relevant Object Enabler is loaded. Object Enablers act as a type of reader allowing additional functionality from plain AutoCAD on the Proxy Graphics.
    Use the command –ExportToAutoCAD (don’t forget the hyphen). It writes out another version of the same file with all Proxy Graphics exploded to plain AutoCAD entities. Installing Object Enablers and any other Hotfixes should help stabilise the drawings. These can be downloaded from the Autodesk website at www.Autodesk.com under the Utilities and Drivers and Updates and Service Packs sections for the relative version of AutoCAD.


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2. Why won’t my xrefs bind and how can I bind problem xrefs?

Binding drawings in AutoCAD can be very problematic, but if users are made aware of what causes the xrefs not to bind most problems can be eliminated before they have started.

I’ve split this into two sections. First I’ll give a list of the most common reasons why drawings won’t bind and the best course of action to avoid them happening, secondly I’ll provide a step by step guide of what to do if your xref/xrefs won’t bind.

Common Reasons Why Xrefs Won’t Bind

  • The most basic reason for xrefs not binding is down to poor maintenance of the drawings. Drawing files that contain errors, unused and damaged data can contribute to binding problems.
    Action:
    To detect and fix errors use the Audit command, to remove unused data from drawings use Purge (in addition be sure to run the command line version of Purge i.e. -Purge and use the Regapps option to clean out unreferenced registered application IDs) to repair damaged data within drawings use Recover. It’s worth noting that for more recent versions of AutoCAD a quick way to perform a Recover on a drawing and all its xrefs is to use File »Drawing Utilities »Recover drawings and xrefs... from the pull down menu.
    Prevention:
    Regular use of the Audit and Purge commands is good practice to optimise drawing performance. Try combining the two commands in a macro and adding to a toolbar for quicker user execution.

  • If a parent xref contains a nested child xref that is the attachment type as oppose to the overlay type, the parent xref will not bind if the nested xref is unloaded in the drawing where the parent xref resides. For example: If you have two xrefs called drawing1.dwg and drawing2.dwg and you xref drawing2.dwg to drawing1.dwg as an attachment (note ?not an overlay) and then xref drawing1.dwg to TitleSheet.dwg as an attachment or overlay (it makes no difference here), this will also drag drawing2.dwg to TitleSheet.dwg. If you then unload drawing2.dwg within TitleSheet.dwg, neither of the xrefs will bind into TitleSheet.dwg.
    Action: Avoid unloading xrefs that are the attachment type ?either use the overlay type of xref or avoid unloading xrefs. Detach any nested unloaded xrefs or change them into the overlay type.
    Prevention: Ensure all users are aware of the differences between attachment and overlay. Design an effective xref structure for all projects prior to starting and ensure all users are aware of it
    .

  • Drawings that have been exported from different CAD systems as DWG files and xrefed straight into your drawings can be particularly troublesome to bind.
    Action:
    Remake the drawing using copy and paste to take the information required only from the exported file, paste it into a clean drawing and substitute the xrefs.
    Prevention: Introduce this procedure across the office as a standard for integrating drawing data from external sources.

  • Similarly drawings that have been backwards saved from later versions of AutoCAD can be a problem to bind, for example a drawing that has been saved back from the AutoCAD 2010 format to the 2004 format. Please note that if the later application of AutoCAD is set to always save in the earlier format problems should not arise.
    Action: Remake the drawing using copy and paste to take the information required from the exported file, paste it into a clean drawing and substitute the xrefs.
    Prevention: Introduce this procedure across the office as a standard for integrating drawing data from later versions of AutoCAD. If you have different versions of AutoCAD within the same office it is advisable to set all machines in the office to save consistently in the same format. This can be done from the Options command, selecting the Open and Save tab and setting the desired format under Save as.
  • Proxy Graphics contained in drawings can also cause problems when binding. These are drawing elements created by AutoCAD vertical products such as ADT or Architecture, MEP, etc. and cannot necessarily be handled by AutoCAD unless the relevant Object Enabler is loaded. Object Enablers act as a type of reader allowing additional functionality from plain AutoCAD on the Proxy Graphics.
    Action: Use the command –ExportToAutoCAD (don’t forget the hyphen). It writes out another version of the same file with all Proxy Graphics exploded to plain AutoCAD entities.
    Prevention: Installing Object Enablers and any other Hotfixes should stabilise AutoCAD and hopefully make the binding process less problematic. These can be downloaded from the Autodesk website at www.Autodesk.com under the Utilities and Drivers and Updates and Service Packs sections for the relative version of AutoCAD.

How to Bind Problem Xrefs

It is advisable to take back-up copies of all drawing files prior to running through these steps. I have put these steps in order of how quick and easy they are to perform so it is worthwhile working through in order.

Reloading the xrefs - A long shot but it is always worth a try as it does occasionally work and is quick to perform:

  • Open the drawing that won’t bind the xref /xrefs
  • Open the Xref Manager / External References Palette
  • Highlight all xrefs, click the Reload button and hit OK
  • Reopen Xref Manager / External References Palette immediately and attempt to bind
  • Should it fail move onto the next step

Check there are no unloaded attachments - Check for unloaded and nested xrefs that are the Attach type.

  • Open the drawing that won’t bind the xref /xrefs
  • Open the Xref Manager / External References Palette
  • Check for any xrefs that are unloaded and are the Attach type
  • Should there be any next use F3 and F4 on the keyboard to toggle between xref structure views to see if they are nested (nested xrefs are routed to the drawing via another xref)
  • If there are any either reload them or open the drawing the xref is nested in and change the xref type to an Overlay
  • Ensure you save and reload xrefs as necessary
  • Attempt to bind again, move onto the next step if it fails.

Perform a cleanup - Clean the host drawing and all xrefs of errors and unused and damaged data.

  • In each of the files mentioned above run the Audit and Purge (in addition be sure to run the command line version of Purge i.e. -Purge and use the Regapps option to clean out unreferenced registered application IDs) commands to remove errors and unused data.
  • Use Recover on each file to repair any damaged data. In more recent versions of AutoCAD a quick way to perform a Recover on a drawing and all its xrefs is to click on File »Drawing Utilities »Recover drawings and xrefs... from the pull down menu.
  • Ensure you save and reload xrefs as necessary.
  • Attempt to bind again, move onto the next step if it fails.

Find the problem xref / xrefs - If you have multiple xrefs in your drawing the first thing to do is find the problematic file or files.

  • Firstly open the drawing that failed to bind the xrefs, check everything is set correctly and Save.
  • From now on do not Save.
  • Open the Xref Manager / External References Palette.
  • Select each xref individually and attempt to bind. Make absolutely sure each xref has bound in successfully by ensuring it has disappeared from the list in the Xref Manager / External References Palette
  • Note if you are using the old style Xref Manager you must hit OK after binding each xref and then re-open the Xref Manager dialogue to check if the bind has been successful.
  • Repeat this process for every xref in the list making a note of each xref that does not bind.
  • Close the title sheet drawing and do not Save.

Remake the problem xref / xrefs ?Once you have identified the problems files you need to remake the drawings. This is the most time consuming method but by far the best way to clean a drawing. After performing the following steps compare file sizes of the old and new files. Very often the cleaned file is far smaller than the original and is therefore an excellent way of keeping files to their minimum size.

  • Make sure you have backed up all xref files to a safe location as you need to remake each one and overwrite it with a new one
  • Also check if the file has any particular settings or variables that may require transferring to the new file, for example, custom UCS, LTSCALE and PSLTSCALE variables
  • In the first xref drawing first perform a Reload on all the xrefs and Thaw, turn On and Unlock all layers
  • Zoom the drawing to Extents
  • From the AutoCAD pull down menu select Edit »Copy with Basepoint enter 0,0 at the command prompt and close the drawing
  • Start a new, clean drawing using your office standard template. For the purposes of this task the template should ideally be completely blank and not contain any standard styles, layers or blocks - if it does delete and Purge as necessary to remove them
  • From the AutoCAD pull down menu select Edit »Paste and enter 0,0 at the command prompt
  • Reapply any settings or variables as noted
  • Save the drawing and overwrite the file the data was taken from
  • Run the Purge and Audit commands and close the drawing
  • Repeat these steps for each xref that would not bind
  • Reopen the title sheet or reload the xrefs if still open and bind again.

Insert the xref / xref as blocks ?If all else fails and time is of the essence, detach the problem xrefs and use the Insert command to place them in the drawing as blocks. Beware when doing this as common layer and block names between xrefs will now merge to the same names so check for any differences in the display of the drawing.
This is a short term fix only and I do not recommend this as a solution.

Should the files still refuse to bind, which is extremely rare, my next approach is to find what element within the drawing is causing the problem. To do this I use Qselect to remove each object type (i.e. blocks, text, hatches, splines, etc) from the offending xref one at a time and reattempt to bind. Once I have identified the offending object I can decide what remedial action to take.

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3. Which bind method should I use ?Bind or Insert?

Firstly, I will outline the main differences between the two methods:

  • the Bind option maintains the same prefixes added to block, layer and style names, etc. as is given to these objects when they are xrefed (except a $0$ is added to the name in place of the |). This maintains the individual identity for each object as if it were xrefed. Be aware as this option adds prefixes to block, layer and style names, etc. Take care not to mix with the office working data as duplication of these entities will occur.
  • the Insert option, however, does not alter the names of objects at all and so all inserted duplicate data will merge with that of the host drawing. Be aware that if there is any duplication of properties for block, layer and style names, the host drawing takes precedence so some incoming data may change.


In my opinion there is no right or wrong way, it just comes down to what the bound file will be used for.

If the bound file is to be used where the integrity of the drawing has to be maintained as for a drawing issue for example, then I would recommend the Bind option.

If the file is for internal use only, where the duplication of block, layer and style names would cause a problem, I would recommend the Insert option.

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4. Which PDF driver should I use with AutoCAD?

There are common problems associated with creating PDFs from AutoCAD such as:

  • gradient hatch contained in the drawing causing the PDF creation to fail
  • wipeouts in the drawing appear as black solids in the PDF itself and/or any hardcopies taken from the PDF
  • random thickening of lines in the PDF.

Many of these problems can be overcome by knowing which is the best suited PDF driver to the version of AutoCAD you are using. In order to ascertain this I have formed two tests using typical architectural type drawings and will create PDFs of them using several different PDF drivers on AutoCAD versions 2008, 2009 and 2010. The PDF drivers I am using are:

  • the Adobe 7.0 PDF driver which a lot of companies use
  • the Autodesk in-built driver included with AutoCAD (PDF to DWG)
  • the PDFill PDF Writer driver which is free to use for both personal and commercial uses and does not have any annoying banners or watermarks

The machine I have used for the tests has an Intel Core 2 Duo Processor @ 2.00ghz with 2GB of RAM and is running Windows XP, the PDFs were all created at an A1 sheet size and a HP printer was used for all hardcopy prints. All relevant information will be displayed in the tables.

Test 1 ?Typical General Arrangement Plan

The first test uses a typical architectural general arrangement plan drawn at a scale of 1:200 which shows the layout of a store and adjacent site information. The drawing contains some text (no true type fonts), basic hatches (no gradient hatch) and some detail reference bubbles that have wipeouts placed within them. This is one of the most common types of drawings that an architectural practice would require to PDF. Please note all drivers were set to 300dpi to maintain a consistent comparison.


AutoCAD Version

PDF driver used

DPI setting

Size of PDF

Time taken to create PDF

Clarity of PDF

Wipeouts created in PDF

PDF hardcopy printed correctly

AutoCAD 2008

Adobe

300dpi

263 KB

12 secs

Fine for general use*

Yes

No, wipeouts did not print correctly **

Autodesk

300dpi

282 KB

7 secs

Fine for general use*

Yes

Yes

PDFill

300dpi

207 KB

8 secs

Fine for general use*

Yes

Yes


AutoCAD 2009

Adobe

300dpi

263 KB

5 secs

Fine for general use*

Yes

No, wipeouts did not print correctly **

Autodesk

300dpi

283 KB

4 secs

Fine for general use*

Yes

Yes

PDFill

300dpi

207 KB

6 secs

Fine for general use*

Yes

Yes


AutoCAD 2010

Adobe

300dpi

263 KB

4 secs

Fine for general use*

Yes

No, wipeouts did not print correctly **

Autodesk

300dpi

257 KB

5 secs

Fine for general use*

Yes

Yes

PDFill

300dpi

207 KB

6 secs

Fine for general use*

Yes

Yes

* The clarity of the PDF print was absolutely fine for general use such as viewing at various zooms and printing.

** The wipeouts printed as black solids, however they did print correctly using the Print as Image workaround as outlined in Section 5.

Test 2 ?Typical Presentation Elevation Type Drawing Containing Gradient Hatch and Wipeouts

For this test I have used an architectural elevation type drawing that would be commonly used for presentation purposes. It contains AutoCAD elements that are typically troublesome to create successfully in PDFs, gradient hatch and wipeouts.

I know from experience that if a drawing contains gradient hatch and the dpi setting of the driver is too high, the PDF creation will normally fail. With that in mind I have used a low base setting of around 150dpi for each driver to ensure the PDF is created. In addition I have included a further set of results for the highest dpi setting that the driver could cope with and these results are shown in italics. For details of how to adjust the dpi settings of each driver please see below.


AutoCAD Version

PDF driver used

DPI gradient hatch created

Size of PDF

Time taken to create PDF

Wipeouts created in PDF

PDF hardcopy printed correctly

AutoCAD 2008

Adobe

144dpi (and 300dpi)

1,720 KB (2,634 KB)

35 secs (4 mins 15 secs)

Yes

No, wipeouts did not print correctly ***

Autodesk

150dpi (and 400dpi)

716 KB (3,800 KB)

20 secs (1 min 20 secs)

Yes

Yes

PDFill

150dpi (and 300dpi)

392 KB (2,081 KB)

35 secs (2 mins 30 secs)

Yes

Yes


AutoCAD 2009

Adobe

144dpi (and 300dpi)

1,710 KB (2,543 KB)

45 secs (4 mins 35 secs)

Yes

No, wipeouts did not print correctly ***

Autodesk

150dpi (and 400dpi)

714 KB (3,824 KB)

26 secs (1 min 50 secs)

Yes

Yes

PDFill

150dpi (and 300dpi)

388 KB (2,064 KB)

50 secs (3 mins 4 secs)

Yes

Yes


AutoCAD 2010

Adobe

144dpi (and 300dpi)

1,710 KB (1,710 KB)

18 secs (3 mins 12 secs)

Yes

No, wipeouts did not print correctly ***

Autodesk

150dpi (and 200dpi)

111 KB (156 KB)

11 secs (18 secs)

Yes

Yes, but with merge line problems ****

PDFill

150dpi (and 300dpi)

388 KB (2,064 KB)

26 secs (3 mins 4 secs)

Yes

Yes

Please note that the clarity of all the PDFs was absolutely fine for general use such as viewing at various zooms and printing.

*** The wipeouts printed with black lines across them, however they did print correctly using the Print as Image workaround as outlined in Section 5.

**** The quality of the print was fine and the wipeouts printed correctly however the appearance of the print was hampered by random lines not merging even though the driver was set to Lines Merge. Bizarrely setting the Merge Control on the driver to Lines Overwrite seemed to merge lines better! The print did print correctly using the Print as Image workaround as outlined in Section 5.

To Amend DPI Settings on Each Driver:

Adobe Driver - Open PC3 file ?Device and Document Settings tab ?Custom Properties button ?Layout tab ?Advanced button ?expand Graphic ?click on Print Quality and set required dpi

Autodesk Driver - Open PC3 file ?Device and Document Settings tab ?Custom Properties button ?and set all resolutions as required

PDFill Driver - Open PC3 file ?Device and Document Settings tab ?Custom Properties button ?Layout tab ?Advanced button ?expand Graphic ?click on Print Quality and set to required dpi.

Conclusion

The Adobe driver is possibly the most commonly used and can produce good quality PDFs, however, it doesn’t seem to be the best suited to AutoCAD. Whilst large file sizes and slow generation can be lived with, the inability to handle wipeouts is a real problem. I know there is a workaround for this but from experience it doesn’t appear to work ?I’ve found even if you tell consultants about this they can soon forget and quickly go back to printing your drawings missing vital information. I realise I have not used the latest version (9.0) for this test, but I have used it elsewhere and experienced the identical wipeout and gradient hatch problems, so would therefore avoid using it for AutoCAD.

The in-built Autodesk PDF to DWG driver that is included with AutoCAD can perform brilliantly with AutoCAD (and so it should) but is constantly let down by niggly problems. If configured correctly it can create small files very quickly and prints gradient hatch and wipeouts without problem. However, with the early version of this driver I experienced problems with random lines thickening which was not acceptable for presentation drawings so I stopped using it (however increasing the dpi setting on the driver may solve this). The 2009 version has so far for me been trouble free, but then the latest 2010 version has behaved erratically when attempting to get lines to merge or overwrite. Although there are some good additional features in this latest driver, I have found it can be problematic.

The PDFill PDF Writer by Plotsoft (download from www.pdfill.com) has proved reliable in all areas, in particular creating the wipeouts and gradient hatch and consistently seems to perform well with AutoCAD. The only drawback is the length of time taken to create higher dpi PDFs that contain gradient hatch, but it’s a small price to pay for consistency and reliability.

In my opinion and looking at the above results, for all round performance and reliability the best PDF driver to use with AutoCAD seems to be PDFill PDF Writer. However, if you can live with the quirks and speed is of the essence, the AutoCAD driver could be a viable option. As and when more information becomes available I will update this section.

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5.The wipeouts in my PDFs don't print properly

The PDF drawing looks fine on screen but when printed the wipeouts appear as a solid black fill. This can normally be attributed to a PDF driver being used that is not completely compatible with AutoCAD. To overcome this there are two things that can be done. Firstly, I will outline a workaround to print the existing drawings correctly and secondly, you need to refer to Section 4 and configure a driver that will handle wipeouts.

Firstly, presuming you are viewing your PDFs with Adobe Reader, you can use this workaround to print the drawings:

  • Open the PDF in Adobe Reader and select Print.
  • From the Adobe pull down menu go to File> Print and select Advanced as shown below.

  • Put a tick in the Print as Image box from the Advanced Print Setup dialogue as below.

  • Click OK and continue with the normal printing process. Once set, this setting should hold and become the default.

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6. I cannot create a PDF from a drawing that contains Gradient Hatch

Creating PDFs that contain gradient hatch is notoriously difficult but it can be done as long as the driver is configured correctly.From my experience failure to produce a PDF that contains gradient hatch can commonly be attributed to the dpi setting for that driver being set too high.Please refer to Section 4 for information on how different PDF drivers perform with AutoCAD when producing gradient hatch and how to change the dpi settings for commonly used drivers.

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