topic Re: Very large XREF causing problems in AutoCAD Forum

Very large XREF causing problems

Anonymous — Thu, 19 Oct 2017 14:17:19 GMT

Hi!

A large xref in my drawing is making autocad very slow and hard to work with. The xref is a part of a map that I'm drawing lines on. The only reason the xref is there is so it can be plotted in the background of my drawing. I won't ever need to use the geometry in any way, it's only there as a visual representation. In other words, there's no reason for it to be so large.

Is there a clever way to greatly reduce the size?

For example, export the xref as a .png and importing it into my drawing? I know you can export and import png's, but it's difficult to get the scale and placement right. I'm hoping there's a better solution.

Re: Very large XREF causing problems

john.vellek — Thu, 19 Oct 2017 14:45:41 GMT

HI @Anonymous,

Please explain what is in the current Xref? does it have a lot of hatches for instance that can be removed? If you like, I can give you a way to send me the file (how big is the file?) and I can make better suggestions.

You might try printing it to a PDF which you can then attach to your file and even snap to PDF geometry using PDFOSNAP.

Please select the Accept as Solution button if my post solves your issue or answers your question.

Re: Very large XREF causing problems

RobDraw — Thu, 19 Oct 2017 16:26:24 GMT

Make a copy of the .dwg and strip out all the unnecessary stuff. Also, purge, audit, etc. to clean up the file.

Re: Very large XREF causing problems

massimo.corradi — Fri, 20 Oct 2017 13:11:22 GMT

Further more, apart purging and audit, here a couple of more suggestions.

Freeze layers that are not necessary to work.

If the xref is clipped remove clipping, that makes large files slow, especially if there are dense hatches.

If you have a single hatch for many separated areas, separate those hatches. The more contours the slower.

Check if objects properties are bylayer, having thousands of objects were properties are set makes a large drawing slow too.

To scale an image were a calculation is not possible to be applied check the command option 'relative' in the scale command. If you also need to rotate, then there is a scale option in the align command.

Re: Very large XREF causing problems

ennujozlagam — Fri, 20 Oct 2017 16:32:12 GMT

Hello, you can try to DXFOUT to R12 and DXFIN again your xref drawings to reduce the file size, purge. Audit, overkill and see if helps. thanks

Re: Very large XREF causing problems

john.vellek — Fri, 20 Oct 2017 18:05:13 GMT

Hi @Anonymous,

I am checking back to see if my post or others helped you with your problem. Please mark a post or posts as accepted solutions if they resolved the issue or give me a bit more detail on this issue so we can continue to work towards getting this solved.

Please hit the Accept as Solution button if a post or posts solves your issue or answers your question.

Re: Very large XREF causing problems

Anonymous — Mon, 23 Oct 2017 07:03:58 GMT

Hi guys. Thanks for your replies.

I wasn't specific enough in my first post, my mistake. What I wanted to ask was this: Is there a way to drastically reduce the file size (from 30+ MB to say 2 MB or less)? Loosing object interactability (if that's a word) is totally fine, as long as it looks the same on screen and on print.

My original approach was to save as .png and try to place and scale the image to fit my drawing. This works ok (image file is less than 1 MB), but I'm hoping there's an easier solution.

The file is a part of a map (with height curves, roads etc). It consists of about one million objects, mostly polylines + a few thousand blocks and is about 32 MB in size. (For the record, I have no idea why it's made like this, I'm new at this company.)
I don't work with the file loaded. I unload it, and only use reload when I'm about to print. But this alone is enough to freeze my pc and make the process of printing a pain.

Overkill reduced the file by about 15 % (32 MB to 27 MB), while purge and audit did not reduce it. DXFOUT -> R12 made a 272 MB file :S
I can of cause freeze / delete everything i don't need, but I was hoping for an easier solution. (I need to see most of the geometry anyway) There are no hatches in the drawing.

Thanks for your help!

Re: Very large XREF causing problems

Anonymous — Tue, 24 Oct 2017 10:18:15 GMT

hi,

use exporttautocad command may be it work try it or wblock

Re: Very large XREF causing problems

john.vellek — Thu, 26 Oct 2017 15:59:40 GMT

Hi @Anonymous,

Can you share the file? I can provide an upload location if you wish. I suspect that printing it to PDF and then using the PDF as an Underlay might be a way to eliminate the size problem.

Please let me know if you would like me to take a look at the DXF for you.

Please select the Accept as Solution button if my post solves your issue or answers your question.

Re: Very large XREF causing problems

Anonymous — Mon, 30 Oct 2017 07:09:13 GMT

Hi @john.vellek

Would be great if you could take a look at it!

Send me instructions, and I'll upload the file. It's about 32 MB.

Re: Very large XREF causing problems

john.vellek — Tue, 31 Oct 2017 14:48:55 GMT

HI @Anonymous,

I took a look at your file and here is what I found:

Audit - 17 errors (12 erased objects)

Purge - 226 zero-length geometric objecgts

-Purge>Regapps - 23 Regapps

I erased some of the data around the edges of your map and then ran an exporttoautocad. After that process I was able to remove 4 more errors using Audit.

I then moved the entire contents close to 0,0.

The file was reduced in size a few MB.

Lastly, I plotted the contents to a DWF which results in a file that is about 3MB. You can attach the DWF to your other files and it should have a much smaller footprint.

I have uploaded my versions of your file to the same location where you shared your file.

Please select the Accept as Solution button if my post solves your issue or answers your question.

Re: Very large XREF causing problems

nathanhayes98 — Tue, 31 Oct 2017 15:23:52 GMT

We had this issue before when using very large x-ref and there was a couple of ways we got around it

- Is your x-ref attached or overlayed? We found when the x-refs were attached they were causing a slow down in the drawing.

- Can your x-ref be clipped? Our x-ref was of a large highway so we cropped the xref down so it only showed the area we wanted, this also improved speed of drawings.

Re: Very large XREF causing problems

Anonymous — Wed, 01 Nov 2017 06:53:03 GMT

Thanks @john.vellek! The .dwf works perfectly. Your method is exactly what I was looking for.

Thanks everyone for your help and ideas!

Re: Very large XREF causing problems

Anonymous — Thu, 24 Oct 2019 19:33:12 GMT

Good Afternoon John,

I've a large Xref file size 27 MB, could you help reduce the size?

Thanks

Re: Very large XREF causing problems

nathanhayes98 — Thu, 24 Oct 2019 19:39:11 GMT

Hi, try the steps below

Trying switching your xref to an overlay rather than attachment if you havent already.

Run the audit command to find and fix any errors in your model.

Run the purge command to get rid of any unused things.

Run purge>regreapps.

Re: Very large XREF causing problems

Anonymous — Wed, 18 Dec 2019 21:04:57 GMT

Thanks for the response. The file is about 70 Mb, could you please help to reduce the size if I send the file?

Re: Very large XREF causing problems

RobDraw — Thu, 19 Dec 2019 12:40:55 GMT

@Anonymous wrote:
Thanks for the response. The file is about 70 Mb, could you please help to reduce the size if I send the file?

There are tons of threads about how to clean up/lighten drawings in this forum and many other places on the internet. Learning about this will teach things that can be used for other tasks.