topic Re: Blocks vs XRef in AutoCAD Forum

Blocks vs XRef

pmercader — Tue, 13 Dec 2016 23:45:50 GMT

I have seen a post with same Title before but that was back in 2008.

I know what blocks are and the difference between blocks and xrefs but my question is - when is it practical to use xrefs vs blocks and/or vice versa?

Personally, I like blocks better than Xrefs simply because xrefs create clutter in the layer properties manager but maybe there are people here with more experience handling xrefs and blocks - would like to get some input.

Thanks!

Re: Blocks vs XRef

john.vellek — Tue, 13 Dec 2016 23:57:16 GMT

Hi @pmercader,

What profession are you working in? That might dictate how you will get responses.

I suggest that if you need to control visibility and colors/transparencies within different viewports then Xref's are probably the right choice. They also let more than one person work on a project at a time and you won't have to fight updating blocks that have attributes.

Please give me some specifics on how you are working and I can try to provide you with some resources.

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

Re: Blocks vs XRef

Kent1Cooper — Tue, 13 Dec 2016 23:58:18 GMT

Xrefs are like Blocks that are defined outside the current drawing. This can have advantages, when you use the same definition in more than one drawing.

The main one is that you can make a change in the source drawing and it will be reflected in all target drawings into which that is Xref'd, as soon as you open each [you don't need to do anything in the target drawings to update the definition]. For instance, a Title Block that's Xref'd into sheets can have the company address or logo or whatever you can imagine updated in the source drawing, and all sheets in all drawings that reference it will be updated with no further effort at all.

Memory savings is another, even more so that with Blocks, because the memory consumption of all the pieces isn't even stored in the target drawings at all [as it would be if you copied the same Block definition around between multiple drawings], but once, outside all of them.

You can set the Layer Manager to not show you all those Xref-dependent Layers:

Re: Blocks vs XRef

pmercader — Wed, 14 Dec 2016 00:13:58 GMT

Hello John,

I am in the Mechanical Design industry but what we mostly work on are 2D flat surfaces like Flexible Circuits.

The structure that we have right now is something like this.

We have a file that contains all the parts and each part has its own layer, we call this file the "MX".

We Xref this file into a new drawing and turn the parts (layers) off that we don't need.

For example:

Lets say I am making the drawing for part 1 - I would then xref the MX and turn all the layers off for part 2, 3, 4 ,5 since I only need part 1 the dimension it accordingly.

Repeat this process for each individual parts.

Re: Blocks vs XRef

RobDraw — Wed, 14 Dec 2016 12:21:28 GMT

For your modeling purposes, blocks are much more appropriate but for title blocks, you could be utilizing XREFs.

Re: Blocks vs XRef

TheCADnoob — Wed, 14 Dec 2016 16:07:50 GMT

I prefer blocks but thats solely because of my current position. I'm the last to see the drawing before they are thrown into the bottomless vault and in order to survive the inevitable complications of DMS switching i like to see the drawing as a single distinct file.

Re: Blocks vs XRef

scot-65 — Wed, 14 Dec 2016 23:52:32 GMT

We Xref third-party files over inserting them as blocks.
One convincing encounter is a Civil DWG file that contained over 1600 layers.
No typo error here.

If we need to extract only pieces, yes, I will wblock, clean up that wblock and
insert this into the destination file (as a block).

Observed downside: Printing chores tend to slow down a little with the xref present.

???

Re: Blocks vs XRef

Alfred.NESWADBA — Thu, 15 Dec 2016 06:56:14 GMT

Hi,

a big point for blocks: they can have attributes and so show different text-like values with every insertion. XRef's can't do that.

- alfred -

Re: Blocks vs XRef

Erense — Thu, 15 Dec 2016 09:39:08 GMT

Usually Blocks will appear more then once per drawing. Especially when they contain attributes like @Alfred.NESWADBA said. So the attributes can have different values for the same blocks.

A Xref is commonly only used once per drawing. (External party drawings, like Steelconsturction, Landscaping/Site or Building)

Re: Blocks vs XRef

Kent1Cooper — Thu, 15 Dec 2016 14:04:14 GMT

@cadacerense wrote:

....

A Xref is commonly only used once per drawing. ....

There are certainly cases in which an Xref is appropriately used multiple times in one drawing. I frequently Xref a Title-block/border drawing into every Layout [sheet] of a multiple-Layout drawing, such as a drawing of something like wall sections that might spread over four or five or more sheets in Layouts. I have also Xref'd a Floor Plan drawing multiple times into a detail-plan-blowup sheet, Xclipping each down to the area I want to blow up [though a similar result can be achieved with one Xref and multiple Viewports]. One might also have reason to have, for example, each distinct apartment layout in an apartment building as a separate drawing file, and Xref the same one into a floor plan drawing more than once, when there are more than one of the same unit on the floor. I'm sure people can think of other situations.

Re: Blocks vs XRef

john.vellek — Thu, 15 Dec 2016 18:18:01 GMT

Hi @pmercader,

The way you describe your process, it sounds like a block library might be more useful.You wouldn't have to carry all the extra stuff into your drawing that way and you could use a more conventional layering method.

Xref's work well for shared information that is used in more than one instance such as on multiple sheets.

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

Re: Blocks vs XRef

Anonymous — Thu, 15 Dec 2016 18:44:54 GMT

Blocks for annotation type work (title-blocks, section marks, detail bubbles, etc.) and components that are model specific and used multiple times. Rule of thumb; "if you need the same component more than twice, make it a block"

Xref's for discipline specific assemblies; foundation, structure, piping, electrical, instrumentation, etc. In complex projects each of these disciplines may contain many separate assemblies.

Re: Blocks vs XRef

john.vellek — Fri, 16 Dec 2016 21:41:08 GMT

Hi @pmercader,

I am checking back to see if my post or others helped you with your problem.
Please add a post with how you decide to proceed and your results so other Community members may benefit.

Please select the Accept as Solution button if a post or posts fully solved your issue or answered your question.

Re: Blocks vs XRef

pmercader — Fri, 16 Dec 2016 22:42:20 GMT

Thanks for all the responses. I guess it all boils down to the intent of what someone is trying to achieve.