Topic: XREF Comparison

[Greg B]

For the sake of a discussion...

How does xref's work in AutoCAD?

Is it a self xref that is clipped and scaled?

Is it a completely different file?


For instance....in DataCAD we have XREF's.

1. We have a completely seperate file that we reference into a drawing.  Typically I have a floor plan, site plan, elevations, sections reference files.  On the floor plan file I will have different levels set up on each other, seperated by layers and able to switch around quickly using a feature called Go to Views.  This will turn on and off layers as I have it set for each floor.

I will then reference this file into a new file that I have labeled as A2-1 FLOOR PLAN or some such name.  When I xref it in I can change the on layers individually or with GTV's.  I also will xref in a titleblock so that I have just one titleblock that I need to change information on and that is a completely seperate file.

2. We can do self xrefs in a file.  This is basically a copy of what you see that can be clipped and layers turned on and off without affecting the rest of the drawing.

So how does AutoCAD work with xref's?

[Slimİ]

1. We have a completely seperate file that we reference into a drawing.  Typically I have a floor plan, site plan, elevations, sections reference files.  On the floor plan file I will have different levels set up on each other, seperated by layers and able to switch around quickly using a feature called Go to Views.  This will turn on and off layers as I have it set for each floor.

I will then reference this file into a new file that I have labeled as A2-1 FLOOR PLAN or some such name.  When I xref it in I can change the on layers individually or with GTV's.  I also will xref in a titleblock so that I have just one titleblock that I need to change information on and that is a completely seperate file.

Very similar to ACAD

2. We can do self xrefs in a file.  This is basically a copy of what you see that can be clipped and layers turned on and off without affecting the rest of the drawing.

I don't believe it is done like that in ACAD, maybe someone else with a newer version of ACAD might know, I have 2k5. I really haven't had a need for this kind of thing.

[Greg B]

If it is similar, then why will I get acad files with the titleblock in the same drawing as the floor plan?

[Slimİ]

It might depend on how things get prepared to send to you.

Sometimes, I will copy my sheet drawing (the one that gets everything XREFed into it), then bind & explode the XREFs, delete all off and or frozen layers (usually calculation layers survey data layers,etc.), purge it six-ways to Sunday and send it off to the client, sub, etc. Hence you get a drawing that apparently has everything in it

[CADaver]

If it is similar, then why will I get acad files with the titleblock in the same drawing as the floor plan?

Because many of us are of the opinion that that is the least intelligent application of XREF's currently in use.

For us:
It does very little for file size in that another block is required for titleblock information.
Titleblock static data is fixed at contract, there will be no need in modifying the titleblock at a later date.
Legacy contracts for the same client have legacy titleblocks and XREFing them would interfere with that.

[ronjonp]

If it is similar, then why will I get acad files with the titleblock in the same drawing as the floor plan?

Also,

I don't know if the software you use supports overlays rather than attach. Sure you may see the titleblock in the floor plan but if it is overlayed and you reference that file into yours as a background (which is what we do).....the titleblock is there no longer.

[Tad]

Why wouldn't you xref a border? Exploded borders is one of the least intelligent practices I come across. I have drawings with 5-50 or more layouts. I'm not going to waste my time changing dates, filenames, etc. that are the same on all sheets. The text that is specific to each sheet is the only text that shouldn't be part of the xref.

Of course some people just don't seem to understand xrefs...

[Krushert]

Of course some people just don't seem to understand xrefs...

But they think and say they do in a similar fashion to a self-proclaimed genius 

[CADaver]

Why wouldn't you xref a border? Exploded borders is one of the least intelligent practices I come across.

No need to make an unintelligent jump from xrefs to exploded blocks, one has nothing whatever to do with the other.

Now to your question. Primarily legacy drawings for the same client may or may not use the same border.  Borders are determined and fixed at contract and there is no reason to change them later.  Considering that even you agree that the volatile data must be in a block for each drawing, nothing is gained by placing the static data in an xref.

I have drawings with 5-50 or more layouts. I'm not going to waste my time changing dates, filenames, etc. that are the same on all sheets.

Judicial application of attributes and global attribute editting solves that easily with the added advantage of extractable data from the attributes.  It should be noted that we do not re-issue the entire package for each revision.  We only revise and re-issue the sheet that changed.

Of course some people just don't seem to understand xrefs...

Not that it matters,  but you might want to make sure there's "bullets in your gun" before you throw down thinly veiled attempts at sarcasm around here.  Some folks here just live to embarrass new posters that zig when they ought to zag. No not me, I wouldn't do that.

[RbtDanforth]

What Randy said :kewl:

I am currently working with a drawing that has the work as xref, the border, and both of those xref-ed into another file with only a block containing the border data, and the two xrefs, that is three dwg files for one drawing :ugly: and as long as there is a block with attributes... why not include the border linework as well? As the other xref is compleat except for a paperspace border, how is it necessary for that to be an xref as well.

As Randy pointed out any of those xrefs might be accidentally over-ridden or changed, and not have been saved at the time of publishing. I have seen many total republishing of 50 drawing sets, it is quite easy to use FIND or a lisp routine to change all the sheets in a single or very few moves.

I have several block update routines (depending on the situation) that make blocks no different than xrefs except, they only change when you tell them to, they are always in the drawing, and they have attributes

[Greg B]

Ok guys.  I get somewhat of a feel for how the xref's work in AutoCAD and when people use them.

I was thinking that the titleblock was put in the drawing to be self-xrefed into a modelspace or paperspace thing a ma jiggy, but I guess not.

What drives me crazy is that the titleblock is usually very very VERY small and way off in space compared to the drawing.  No way of knowing a scaling factor what so ever.  Why is it done this way?

[nivuahc]

2. We can do self xrefs in a file.  This is basically a copy of what you see that can be clipped and layers turned on and off without affecting the rest of the drawing.

I don't believe it is done like that in ACAD, maybe someone else with a newer version of ACAD might know, I have 2k5. I really haven't had a need for this kind of thing.

Model Space/Paper Space, if I'm reading Greg properly.

[RbtDanforth]

What drives me crazy is that the titleblock is usually very very VERY small and way off in space compared to the drawing.  No way of knowing a scaling factor what so ever.  Why is it done this way?

Autocad does not need a block sitting somewhere visable to be referenced. There is a 3d space for models (usually only 2d work there) and then there are as many 2d tabs as you want. The tabs are virtual paper, each one a sheet (normally). The border is placed in these "paper" tabs in the size of the actual paper.

The tricky bit is that you create "holes" that look into model space in the direction, scale, and location you assign. It is in these "holes" that scaling happens. Each "hole" can also freeze layers without affecting how they are in any other "holes". Once everything is set the "holes" can be locked so the relative connection is fixed.

There is some controversy about what goes in the model area and what is with the Border in the paper tab area. Personally I push as much as possible into the paper area unless it shows up on multiple sheets or is fixed to a specific spot on the model. Other folk push for nothing but the border there. Awareness of how to manipulate the paper area is often the deciding factor.

[CADaver]

I was thinking that the titleblock was put in the drawing to be self-xrefed into a modelspace or paperspace thing a ma jiggy, but I guess not.

ummm... wha??

XREFs in AutoCAD are just blocks, the only difference is the definition of the block is a file outside the current file.  So it has an insertion point like a block and is "inserted" sorta like a block.  When used as backgrounds, XREFs are usually attached/overlain at 0,0,0 so that all things line up.  For a border, be it a block or an XREF, it's insertion point is the lower left corner, and it's inserted/overlain in PAPERSPACE at 0,0.  At least thats how we do it.

What drives me crazy is that the titleblock is usually very very VERY small and way off in space compared to the drawing.  No way of knowing a scaling factor what so ever.  Why is it done this way?

The border is real size 1:1, that means a 24x36 border is just that, 24" by 36".  It is then placed in PS on a layout tab at a scale of 1.  Viewports are opened and zoomed to the proper scale for presentation and located on that sheet.

[ronjonp]

On a tangent.....I hate when I recieve titleblocks from a client that are exactly 24x36 size. Am I missing something here or does everyone else have printers that don't utilize margins? A 36" titleblock will not fit on a 36" roll unless rotated then each sheet has to be trimmed :pissed:. Same for 22x34 when printing "true halfscales".

Back to your regularly scheduled program...

[whdjr]

On a tangent.....I hate when I recieve titleblocks from a client that are exactly 24x36 size. Am I missing something here or does everyone else have printers that don't utilize margins? A 36" titleblock will not fit on a 36" roll unless rotated then each sheet has to be trimmed :pissed:. Same for 22x34 when printing "true halfscales".

Back to your regularly scheduled program...

  OOOOOOOOO!!!!!!!!!  I hate it when the do that.  We have Civil engineers that send us 30x42 sheets that they printed on 36" wide paper and then trimmed.  The edges are never straight.

[Slimİ]

On a tangent.....I hate when I recieve titleblocks from a client that are exactly 24x36 size. Am I missing something here or does everyone else have printers that don't utilize margins? A 36" titleblock will not fit on a 36" roll unless rotated then each sheet has to be trimmed :pissed:. Same for 22x34 when printing "true halfscales".

Back to your regularly scheduled program...

  OOOOOOOOO!!!!!!!!!  I hate it when the do that.  We have Civil engineers that send us 30x42 sheets that they printed on 36" wide paper and then trimmed.  The edges are never straight.

Same goes for those lousy "Artichokes" and their 30X42 bedsheets.  Thinkin' they be the center of the universe, when we Civils (even our name is polite) have the REAL world to deal with.

[Dinosaur]

Exactly . . . they probably are having to print it on rollstock and pull the ripcord just to get close to that size sheet.

[Slimİ]

Oh, and by the way we have 30" rolls in our plotter just for 30x42...

[CADaver]

On a tangent.....I hate when I recieve titleblocks from a client that are exactly 24x36 size. Am I missing something here or does everyone else have printers that don't utilize margins? A 36" titleblock will not fit on a 36" roll unless rotated then each sheet has to be trimmed :pissed:. Same for 22x34 when printing "true halfscales".

Ours plot on 36" paper on our plotter without trimming.  The corner to corner of the border rectangle is 23"X34" and is offset 1" to the right, with 1/2" plotter margins all around it's jes' rit.

[Slimİ]

Ours plot on 36" paper on our plotter without trimming.  The corner to corner of the border rectangle is 23"X34" and is offset 1" to the right, with 1/2" plotter margins all around it's jes' rit.

Same here...

[ronjonp]

On a tangent.....I hate when I recieve titleblocks from a client that are exactly 24x36 size. Am I missing something here or does everyone else have printers that don't utilize margins? A 36" titleblock will not fit on a 36" roll unless rotated then each sheet has to be trimmed :pissed:. Same for 22x34 when printing "true halfscales".

Ours plot on 36" paper on our plotter without trimming.  The corner to corner of the border rectangle is 23"X34" and is offset 1" to the right, with 1/2" plotter margins all around it's jes' rit.

Same here...

[CADaver]

I don't like it when people agree with me, makes me nervous...