Author Topic: Why do you civil and surveyors still scale geometry  (Read 26503 times)

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Greg B

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Re: Why do you civil and surveyors still scale geometry
« Reply #30 on: September 12, 2006, 11:46:41 AM »
You guys are thinking way to complicated...

I'm talking about stuff that should be easy, but some people just can't visualize a way to make something work.

For instance, getting a double door into a bedroom that doesn't seem like it should be able to.

The architect I work with can be given a lot of restrictions and requests and make them work out.

I have my share of grips about architects, but a lot of them can visualize and put to paper concepts that should work where people like me can't even begin to figure out.

sinc

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Re: Why do you civil and surveyors still scale geometry
« Reply #31 on: September 28, 2006, 02:42:45 PM »
I don’t care in what format it is but (because maybe I was always told this) but draw 1 unit to 1 unit regardless of what the format of measurements is.
Exactly.  The problem arises when the surveyors work with 1 unit = 1' and the archies work with 1 unit = 1"
OK, We have a problem and have identified it.  Is there a viable solution other than each discipline converting the others drawings as we are currently doing?  I am stuck with my data format and software requirements as are the archtichoke types.

The new behavior of Autocad (in 2006 or 2007, whichever it was) is supposed to partially take care of this issue.

If the architect's drawing has INSUNITS=inches and the Civil drawing has INSUNITS=feet, then you can INSERT or XREF the architect's drawing into the Civil drawing (or vice-versa), and the proper scaling will automatically happen.  You still may have a problem with horizontal alignment, though, since Architects usually use assumed coordinate systems and Civil people usually use Project or State Plane coordinates, but the scaling is supposed to be automatic.  In fact, a drawing with INSUNITS=inches will be properly scaled when inserted into a drawing with INSUNITS=meters, etc.

The problem is that people need to learn the correct way of using these features.  As it is now, it seems a lot of people don't seem too interested.  Instead, they're just throwing their hands up in disgust over the change in behavior of the XREF and INSERT commands, and doing things like setting INSUNITS=0 in the ACADDOC.LSP file in an attempt to revert to the old behavior.  As long as people continue doing stuff like that, it will continue to be a problem.

Obviously, there is still a problem with text and symbols, since the desired size of those items is determined by the settings of the viewport that is used for plotting, and not by the drawing units.

Krushert

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Re: Why do you civil and surveyors still scale geometry
« Reply #32 on: September 29, 2006, 09:45:49 AM »
The new behavior of Autocad (in 2006 or 2007, whichever it was) is supposed to partially take care of this issue.

If the architect's drawing has INSUNITS=inches and the Civil drawing has INSUNITS=feet, then you can INSERT or XREF the architect's drawing into the Civil drawing (or vice-versa), and the proper scaling will automatically happen.  You still may have a problem with horizontal alignment, though, since Architects usually use assumed coordinate systems and Civil people usually use Project or State Plane coordinates, but the scaling is supposed to be automatic.  In fact, a drawing with INSUNITS=inches will be properly scaled when inserted into a drawing with INSUNITS=meters, etc.

The problem is that people need to learn the correct way of using these features.  As it is now, it seems a lot of people don't seem too interested.  Instead, they're just throwing their hands up in disgust over the change in behavior of the XREF and INSERT commands, and doing things like setting INSUNITS=0 in the ACADDOC.LSP file in an attempt to revert to the old behavior.  As long as people continue doing stuff like that, it will continue to be a problem.

Obviously, there is still a problem with text and symbols, since the desired size of those items is determined by the settings of the viewport that is used for plotting, and not by the drawing units.

Very informative, thanks; though that feature is not happening for me even though I have AC2007.  Don’t know what the surveyor uses.  Does this feature only work between 2006 & 2007 and not with earlier releases???

Can some one explain the logic behind these three variables?  Autodesk has a done a poor job again (IMHO) of explaining the "hows and whens" so that the user can get the desired results that he wants.

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sinc

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Re: Why do you civil and surveyors still scale geometry
« Reply #33 on: September 29, 2006, 11:04:49 PM »

Can some one explain the logic behind these three variables?  Autodesk has a done a poor job again (IMHO) of explaining the "hows and whens" so that the user can get the desired results that he wants.


The basic premise is rather simple.  Basically, INSUNITS is the same thing as modelspace Drawing Units.  Just set the INSUNITS to the appropriate value for how you work.  If you work with 1 modelspace drawing unit = 1 inch, then set it to inches (INSUNITS=1).  If you work in 1 du = 1 foot, set it to feet (INSUNITS=2), etc.  You may prefer to select the value you want by going to Format->Units... and selecting the units from the list; this has the same effect as setting INSUNITS, and you don't have to remember which number is which unit.

Starting in 2006, when you INSERT or XREF a drawing, Autocad uses this setting in each drawing to determine how to scale the block.  If INSUNITS = Inches in the block, but INSUNITS = Feet in the active drawing, the block will be scaled by .08 as it's inserted (1 inch = 0.08 feet).  The same thing happens with XREFs.

-

The easiest way to see how it works may be to create a new drawing, and draw a circle at (0,0) that has a radius of 1 drawing unit.  Set the INSUNITS to Inches, and save the drawing as "inch.dwg".  Now change the INSUNITS to Feet, and save the drawing as "foot.dwg".  Then change INSUNITS to Meters, and save the drawing as "meter.dwg".  This creates three blocks - all circles, one with radius = 1 inch, one with radius = 1 foot, and one with radius = 1 meter.  In each case, the radius is also 1 drawing unit.

Now create a new blank drawing.  Set the INSUNITS for the new drawing to Inches.  INSERT each of the "inch", "foot", and "meter" blocks in turn as blocks, making sure that you don't explode the blocks.  (You probably want to use the "Specify on screen" option for Insertion Point.)  Notice that each circle is a different size, even though all three blocks were created using a circle with a radius of 1 drawing unit.  Measure the radius of each circle, and you will see that the "Inch" block has a 1-inch radius, the "foot" block as a 12-inch radius, and the "meter" block has a ~39.37-inch radius.  Now click on each block in turn, and look at the Properties for each block.  Note the "Unit Factor" property, which contains the scaling value that Autocad calculated by using the units.  Also notice that in each case, the X Y and Z scale factors are all set to 1.  To get the total scale value applied to the block, multiply the X and Y and Z scale factors by the "Unit Factor".

Now change the INSUNITS for the current drawing to Feet.  Note that the size and appearance of the three blocks in the drawing does not change, i.e., each block still covers the same number of drawing units.  But now each drawing unit represents a different unit of length.  If you measure the circles, the "inch" circle that used to measure 1 inch now measures 1 foot; the "foot" circle that used to measure 12 inches now measures 12 feet, etc.  But if you look at the Properties, they will look different.  They will now have different "Unit Factors", and the X Y and Z scale factors will have compensating values.

With the INSUNITS still set to Feet, insert the three blocks again.  (You can just start the INSERT command and select the blocks from the list; you don't need to browse to them again.)  Notice how they get inserted this time.  If you measure the new circles you just inserted, the "inch" circle that measured 1 inch the first time you inserted it will measure ~.08 feet this time around; the "foot" circle that used to measure 12 inches now measures 1 foot, etc.  Now change the INSUNITS of the current drawing to Meters, and do the same thing again.  Experiment with this for a while, until you feel comfortable with what's happening.

There is also a "Unitless" setting.  If either the source or destination drawings is set to "Unitless", then Autocad will use whatever is specified in the two fields in OPTIONS, User Preference tab->Insertion Scale.  Setting these values in OPTIONS is the same thing as setting the INSUNITSDEFSOURCE and INSUNITSDEFTARGET system variables.  The "Source" would be the drawing you are INSERTing or XREFing; the "Destination" would be your currently-active drawing.

Now for the CAVEATS (surprise!)   :lol:

The problems started when Autodesk changed the behavior of INSERT and XREF so that they automatically get scaled by this value.  The standard block libraries included with Land Desktop were all defined with INSUNITS = Inches.  But most Civil people work with INSUNITS = feet.  (I've even heard some people complain of Land Desktop trying to be "helpful" and changing INSUNITS to Feet for them, but I'm not sure under what circumstances.)  Since Autocad used to ignore this value during inserts, no one really noticed that all the blocks were defined with INSUNITS = inches.  But starting in 2006, all of a sudden all Civil people had the annoying problem of all their blocks coming in scaled by 1/12 because of the INSUNITS.  There are two possible fixes: 1) change INSUNITS for all blocks in block libraries to Feet, or 2) change INSUNITS for all blocks in block libraries to Unitless and set INSUNITSDEFSOURCE to Feet.  We've been using Option 2 here, but I've been thinking Option 1 might be better...

Another problem: the "Feet" option for units is really "International Feet".  Autodesk seems not to have realized that, at least in some states in the US, people still use US Survey Feet, and not International Feet.  One US Survey Foot = 1200/3937 meters = 0.304800609601219... meters, while one International foot is defined as 0.3048 meters exactly.  The difference may not be noticeable most of the time - you wouldn't notice the difference at all with a 100' chain - but it makes a significant difference when things like State Plane Coordinates are involved.  Autodesk does not include an option for "US Survey Feet", reducing the usefullness of the whole system, at least for us here in Colorado.  The difference generally doesn't matter when inserting an architect's floor plan for a building into a civil site plan, since it amounts to a bit over 0.01 feet per mile, but it can matter for other things.

Also, the "new" way of creating block libraries involves putting a whole bunch of blocks in a single drawing.  In other words, one drawing serves as a "container", holding a whole set of blocks inside it.  Then you use the Design Center to turn the container drawing into a Tool Palette, full of Block Tools (or just use the Design Center to pull the block out of the "container" drawing and insert it into your current drawing).  In this way, you can create block libraries out of Dynamic Blocks, which must exist inside of another drawing.  The "container" drawing holds all the dynamic blocks, which are inserted into your current drawing using the Block Tools in the Tool Palette.

But there is another caveat when creating block libraries in this fashion, if you define blocks as "Unitless".  As you create a block, you can define its units, and the block remembers the units.  However, if the block's units are set to "Unitless", Autocad will then look at the drawing units of the "container" drawing.  So, you have to make sure the INSUNITS of the "container" drawing is also set to "Unitless".
« Last Edit: October 02, 2006, 08:16:13 AM by sinc »

Dinosaur

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Re: Why do you civil and surveyors still scale geometry
« Reply #34 on: September 30, 2006, 12:22:46 AM »
Thank you sinc, that is the best explanation I have come across for how to deal with post 2005 insunits.  I have heard that some xrefs in existing drawings also blew up due to the insunits changes when they were opened in 2006.  I have not seen it happen, but my 2006 experience was all new work in Civil 3D.  Have you seen any of this behavior?  If I am actually pull off this move to 2007 from 2005, I am going to have a pile of blocks to change as you described.  I think right now the unitless setting is just putting off the inevitable and it may be best to just change them all and do some housekeeping on several while everything is already disrupted.

Bob Garner

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Re: Why do you civil and surveyors still scale geometry
« Reply #35 on: September 30, 2006, 10:30:37 AM »
My complements on a great explanation, Sinc!

PHX cadie

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Re: Why do you civil and surveyors still scale geometry
« Reply #36 on: September 30, 2006, 11:20:17 AM »
Starting in 2006, when you INSERT or XREF a drawing, Autocad uses this setting in each drawing to determine how to scale the block.  If INSUNITS = Inches in the block, but INSUNITS = Feet in the active drawing, the block will be scaled by .08 as it's inserted (1 inch = 0.08 feet).  The same thing happens with XREFs.

Thank You AutoDesk! (I've often wondered why this is not automatic)
and also to you sinc!
now I want an upgrade
Acad 2013 and XM
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sinc

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Re: Why do you civil and surveyors still scale geometry
« Reply #37 on: September 30, 2006, 12:00:38 PM »
Thank you sinc, that is the best explanation I have come across for how to deal with post 2005 insunits.  I have heard that some xrefs in existing drawings also blew up due to the insunits changes when they were opened in 2006.  I have not seen it happen, but my 2006 experience was all new work in Civil 3D.  Have you seen any of this behavior?

I could see how that would happen.  It would be something like the following:

In Pre-2006 Autocad, a Civil person receives a foundation plan from an Architect.  The Architect drawing is done in Inches, while the Civil drawing is in Feet.  So the user manually scales the XREF by 1/12 as it is inserted by adjusting the X Y and Z scale factors.

Now the user opens the drawing in 2006 or 2007.  As the drawing is opened, Autocad loads the XREF, applying the "Unit Factor" scaling that Pre-2006 did not apply.  Then it also applies the X Y and Z scale factors set by the user.  Net result is that the XREF gets scaled by 1/12 twice.  The fix is to reset the X Y and Z scale factors to 1, so that only the "Unit Factor" scaling is used.

I agree with all of you - Autodesk should have done a better job explaining this change.  That was another part of what upset people - the change was not clearly described, so people were surprised by it.  Suddenly, XREFs and blocks are getting scaled in strange ways that never happened before, and the users had no idea why.  Then, when they figure out why, they discover that they may have to change hundreds of drawings to get everything working correctly again, and Autodesk did not include a utility to make this easier.  Thus the complaints.  (POSSIBLE CHALLENGE: write the utility that Autodesk should have included in 2006 when they made this change, i.e. a script that changes the INSUNITS of all drawings in a directory or directory tree to the value specified by the user...)

This behavior also causes another related problem that some people may have noticed.  As an example, DOT people usually use Microstation, since the US DOT adopted Microstation over Autocad as the "official" CAD program for the DOT.  And at one point, there was a big push to get everyone to switch to Meters over Feet (partly because of the US Survey Foot vs. International Foot problem, partly because metric is just plain easier to use than Imperial units), but the whole push failed miserably.  But a lot of plan sets for DOT projects were created in metric units in Microstation.  Many of these projects were shelved because of budget reasons, and are being built now.  These Microstation drawings may be converted to DWG format and have the units erroneously set to the wrong value by the DWG to DGN converter, i.e. units are set to "kilometers" instead of "meters", or "meters" instead of "millimeters".  New drawings created by the user in Autocad will almost certainly have the INSUNITS = meters.  When the user tries to INSERT or XREF the DOT drawings into the Autocad "Meter" drawing, they will blow up by 1000 times because of the INSUNITS.  This is basically the same problem as the Inches/Feet problem, except it's with Kilometers/Meters or Meters/Millimeters.  Again, the solution is to open the DWG that came from the DOT and change the INSUNITS to the correct value before doing any XREFs or INSERTs.

The INSUNITS thing actually works OK now as long as the users all understand it, and set it appropriately (except for the problems created for anyone who uses US Survey Feet instead of International Feet).
« Last Edit: September 30, 2006, 12:32:51 PM by sinc »

sinc

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Re: Why do you civil and surveyors still scale geometry
« Reply #38 on: September 30, 2006, 12:09:50 PM »

POSSIBLE CHALLENGE: write the utility that Autodesk should have included in 2006 when they made this change, i.e. a script that changes the INSUNITS of all drawings in a directory or directory tree to the value specified by the user...


As an additional feature, make it so that the script also makes sure that that stupid ADCADD_ZZ block is purged at the same time, getting rid of all those stupid "Duplicate definition of block ADCADD_ZZ ignored" error messages we Land Desktop users have been forced to suffer with for years now...
« Last Edit: September 30, 2006, 12:15:08 PM by sinc »

Krushert

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Re: Why do you civil and surveyors still scale geometry
« Reply #39 on: October 02, 2006, 08:29:27 AM »
Thanks for the Explanation Sinc.
Very worthy of tucking that one in a safe spot for future reference.
A round is on me if you are in my neck of the woods.  :-)

I know have to do some research on what my block libraries settings are.

Again thanks.
I + XI = X is true ...  ... if you change your perspective.

I no longer CAD or Model, I just hang out here picking up the empties beer cans

sinc

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Re: Why do you civil and surveyors still scale geometry
« Reply #40 on: October 02, 2006, 10:09:42 PM »
No problem. 

BREZI

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Re: Why do you civil and surveyors still scale geometry
« Reply #41 on: March 13, 2007, 09:01:34 AM »

Good question.

1 = 1mm so why make 1=1m

or 1 = 1" so why make 1 = 1foot!

I think in the old days back in the 80's when floppy disks where used, it mattered becuase drawing files were smaller if you reduced scale factor.

But now it should not matter.

Does my head in, engineers come and ask me why is this not to scale, and we have to scale by 1000 to get it to 1:1.

arghhhh :pissed: :realmad:

Josh Nieman

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Re: Why do you civil and surveyors still scale geometry
« Reply #42 on: March 13, 2007, 09:26:24 AM »

Good question.

1 = 1mm so why make 1=1m

or 1 = 1" so why make 1 = 1foot!


I think you missed the point parade.

Bryco

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Re: Why do you civil and surveyors still scale geometry
« Reply #43 on: March 13, 2007, 09:53:19 AM »
Good stuff sinc,
xrefing a dwg in is definately the least frustrating way to work with other units.
I think the blockunit property should be read write so it could be changed in the property box.
I use inches and have had to make a mm template for the odd job. I hope I'm missing something but it seems I need another set of dims (modelspace notes and dims) and plotconfigs  for both centimeter and meter dwgs. There's no magic button.
« Last Edit: March 13, 2007, 09:54:40 AM by Bryco »

mjfarrell

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Re: Why do you civil and surveyors still scale geometry
« Reply #44 on: May 09, 2007, 01:35:40 PM »


I think in the old days back in the 80's when floppy disks where used, it mattered because drawing files were smaller if you reduced scale factor.


Scaling the geometry would not reduce the number of geometry points, or the file size.

Truth is the real problem is how autodesk scales the unit cube, whenever the Arch units is set,
INSTEAD of setting the dimension units to scale properly and allow for ARCH input to be interpreted correctly by the command line; and then we could all play with the same cad data, except the odd case when somebody moves the site from it's real world coordinate location.
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Michael Farrell
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