Author Topic: Why do you civil and surveyors still scale geometry  (Read 27423 times)

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Krushert

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Why do you civil and surveyors still scale geometry
« on: September 11, 2006, 09:31:42 AM »
Just a simple question as to why?

Why do you civil and surveyors still scale the geometry 1/12 in model space.  With the paper space and speed of computers you can draw everything one to one.  It is a pain in the A\$\$ that I have scale objects up or down with going back and forth from civil drawings to architectural drawings.  Twisting the UCS is more of pain but the reason I understand so live with it.  The scaling part I can’t see the reason?

I just spent the better part of Friday morning grabbing (did not get a chance to post [gripe] until now) all the property lines and markers from the civil cad file and untwisting the ucs, changing the cursors snapang back to zero and scaling the geometry up to full.  Then xref my buildings into the file.  I have new building going along side of an existing building with the new building being located from the set backs not the existing building.  The little connector piece (supposedly the grand entry :ugly:) we need to get fairly close to what it is going to be.

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

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Dinosaur

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Re: Why do you civil and surveyors still scale geometry
« Reply #1 on: September 11, 2006, 10:00:56 AM »
The units for civil engineering are feet instead of inches.  All of the design software performs the calculations and generates the linework in feet and decimals thereof as are all of our formula for design calculations.  In fact, except for certain structures, inches do not exist in engineering projects and NEVER in a survey.
I understand your frustrations.  I go through the same scaling issues only in reverse every time I deal with an architectural drawing.  Rotation is also a problem, particularly when we have to assign bearings of property lines based from true North and we find the entire coordinate system has been rotated to some random angle to make one wall line up with the sheet rather that twisting the view to get the same effect.

Krushert

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Re: Why do you civil and surveyors still scale geometry
« Reply #2 on: September 11, 2006, 10:26:51 AM »
The units for civil engineering are feet instead of inches.  All of the design software performs the calculations and generates the linework in feet and decimals thereof as are all of our formula for design calculations.  In fact, except for certain structures, inches do not exist in engineering projects and NEVER in a survey.
Thanks for making it clear why the decimal feet though i was assuming this was case just wasn’t sure.  And I am okay with that and can work with decimal even though it hurts when I am forced to think.

But you still haven’t explained the reason for scaling.  Lets say I go out side and lay a Surveyors tape measure along side an Architectural tape measure and compare the where a foot markings are.  They are exactly same point. A foot is a Foot.  But in Cad they are not.  I have to scale down so that a 1" architectural equals a 12" in surveyor units.

I understand your frustrations.  I go through the same scaling issues only in reverse every time I deal with an architectural drawing.  Rotation is also a problem, particularly when we have to assign bearings of property lines based from true North and we find the entire coordinate system has been rotated to some random angle to make one wall line up with the sheet rather that twisting the view to get the same effect.
LOL. Hey we are not the ones twisting anything.  We use it just as it comes out of the box.  I only rotate the UCS when the building is being aligned with the setbacks.  I have to go look up the DView command name every time I have to work with a surveyor's drawing.  I am okay with this because I understand the True north "angle".

« Last Edit: September 11, 2006, 10:28:46 AM by Krushert »
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David Hall

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Re: Why do you civil and surveyors still scale geometry
« Reply #3 on: September 11, 2006, 10:27:43 AM »
I also have to deal with both sides of this coin.  Its a fact of life, so working with it is much easier than against.  Even though the 1/12 scale is hard to work with, I do enjoy the decimal feet over inches b/c that is much easier to use.  Its just like metric, everything based on 10.  EASY
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David Hall

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Re: Why do you civil and surveyors still scale geometry
« Reply #4 on: September 11, 2006, 10:31:08 AM »
But you still haven’t explained the reason for scaling.
I think your frusteration is not with the survey drawing, but the ASSUMPTION by autocad that your drawing in INCHES.  So when you measure something, it converts it to feet and inches, and you then have to figure out how many feet it really is.  If Autocad didn't assign ft/in to a drawing by default, you probably would never notice the change.

Its not really scaled down, Autocad just makes you think it is.  A unit is a unit, but what we assign to it is where the confusion lies.  If I said 1 unit=1 cubit, you would ask "How big is a cubit?"  Then in your mind, you would convert to inches so that it is easier to think of in your mind.  This is the same.  If a unit in Acad=1 Foot/12 inches, then you would think of everything in ft.  So if you were to set your units to decimal, if it said 23.5, you would see 23'6" or 23' and 0.5' (I separated that on purpuse to make it clear)

The big problem is Autocad.  There is an assuption that cad makes, your either inches or MM, thats the basic unit.  We have to remember that a unit is a unit, not an inch in all drawings
« Last Edit: September 11, 2006, 10:37:48 AM by CmdrDuh »
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Dinosaur

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Re: Why do you civil and surveyors still scale geometry
« Reply #5 on: September 11, 2006, 10:45:47 AM »
But you still haven’t explained the reason for scaling.  Lets say I go out side and lay a Surveyors tape measure along side an Architectural tape measure and compare the where a foot markings are.  They are exactly same point. A foot is a Foot.  But in Cad they are not.  I have to scale down so that a 1" architectural equals a 12" in surveyor units.
That is the UNITS setting.  Our drawings are set up as CmdrDuh said, in something similar to metric only we use feet instead of meters.  We have to use a scale of 1"=20 drawing units or 1" = 50 drawing units, etc. to acurately represent our design.  I repeat INCHES DON'T EXIST except for structures and then we have to make the conversion ourselves.

LOL. Hey we are not the ones twisting anything.  We use it just as it comes out of the box.  I only rotate the UCS when the building is being aligned with the setbacks.  I have to go look up the DView command name every time I have to work with a surveyor's drawing.  I am okay with this because I understand the True north "angle".

If your project has been twisted so that the bearings on the lot lines when put into surveyor units list out anything other than those indicated on the survey, it was twisted by someone other that the survey guy unless he muffed the conversion when he tried to help you out by getting it back into whatever wacked out system it was in when he got it.

EDIT

Yeah, what CmdrDuh said too
« Last Edit: September 11, 2006, 10:47:28 AM by DinØsaur »

Krushert

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Re: Why do you civil and surveyors still scale geometry
« Reply #6 on: September 11, 2006, 11:12:50 AM »
That is the UNITS setting.  Our drawings are set up as CmdrDuh said, in something similar to metric only we use feet instead of meters.  We have to use a scale of 1"=20 drawing units or 1" = 50 drawing units, etc. to accurately represent our design.  I repeat INCHES DON'T EXIST except for structures and then we have to make the conversion ourselves.

Okay I see it is a units thing and I some what understand though I am not totally agree with the methodology on the scaling part.  I have worked as manufacturing engineer and have work with decimal inches and before that as ship-fitter I worked with all the maritime formats of measurements.  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.

If your project has been twisted so that the bearings on the lot lines when put into surveyor units list out anything other than those indicated on the survey, it was twisted by someone other that the survey guy unless he muffed the conversion when he tried to help you out by getting it back into whatever wacked out system it was in when he got it.

EDIT

Yeah, what CmdrDuh said too
LOL.  From the half a dozen survey/civil consultants that we use; everyone seems to have a different way of doing things.  Like a I said the new building is located along side an existing building.  The existing building is oriented horizontally but the new wing is angled (roughly 135 degrees) to existing.

Thanks guys.

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

Dinosaur

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Re: Why do you civil and surveyors still scale geometry
« Reply #7 on: September 11, 2006, 11:36:22 AM »
Okay I see it is a units thing and I some what understand though I am not totally agree with the methodology on the scaling part.  I have worked as manufacturing engineer and have work with decimal inches and before that as ship-fitter I worked with all the maritime formats of measurements.  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.
This is the heart of the problem
The big problem is Autocad.  There is an assumption that cad makes, your either inches or MM, that's the basic unit.  We have to remember that a unit is a unit, not an inch in all drawings

Autodesk itself even forgot this when they changed the assumed units from unitless to inches in r2006.  Even their own "out of the box" blocks were brought in 12x larger than intended and xrefs than were previously positioned correctly came in at the wrong insertion point and scaled up 12x. :realmad:

We do not scale anything.  Our data comes to us in the form of 123.45 units meaning 123.45 feet.  If the survey is in meters it would mean 123.45 meters.  The same holds true for cubits, rods, chains or parsecs, and of course inches where the scale factor is . . . 12

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Re: Why do you civil and surveyors still scale geometry
« Reply #8 on: September 11, 2006, 01:39:03 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"

Dinosaur

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Re: Why do you civil and surveyors still scale geometry
« Reply #9 on: September 11, 2006, 02:07:38 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.

David Hall

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Re: Why do you civil and surveyors still scale geometry
« Reply #10 on: September 11, 2006, 03:04:13 PM »
the easy solution is to scale your xref of the others work, 0,0 hasn't moved , so the scale change is easy.  Thats what I do.
Everyone has a photographic memory, Some just don't have film.
They say money can't buy happiness, but it can buy Bacon and that's a close second.
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Dinosaur

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Re: Why do you civil and surveyors still scale geometry
« Reply #11 on: September 11, 2006, 03:17:41 PM »
Xrefs work great most of the time, but it seemed like Krushert was working off the drawing directly.  Unfortunately sometimes 0,0 DOES get moved by someone who doesn't understand the implications, but that is a "different kind of problem".  One very good thing about the xref is that once the scale and rotation are set, even if the plan changes completely, if they haven't messed with the origin or rotation you can just point the xref to the new drawing file.  Everything should fall into place and any layer settings carry over from the old xref.

LE

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Re: Why do you civil and surveyors still scale geometry
« Reply #12 on: September 11, 2006, 04:07:46 PM »
« Last Edit: September 11, 2006, 04:10:47 PM by LE »

Krushert

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Re: Why do you civil and surveyors still scale geometry
« Reply #13 on: September 11, 2006, 04:13:51 PM »
archies

That nickname is no problem it Dino's that I take issue with.  Just becasue of a few bad apples, jeez.

archtichoke types.

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

Krushert

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Re: Why do you civil and surveyors still scale geometry
« Reply #14 on: September 11, 2006, 05:19:15 PM »
Xrefs work great most of the time, but it seemed like Krushert was working off the drawing directly.  Unfortunately sometimes 0,0 DOES get moved by someone who doesn't understand the implications, but that is a "different kind of problem".  One very good thing about the xref is that once the scale and rotation are set, even if the plan changes completely, if they haven't messed with the origin or rotation you can just point the xref to the new drawing file.  Everything should fall into place and any layer settings carry over from the old xref.

I was directly working off the surveyors drawing but I then copied his Property Lines into my drawing so I can align my new building with PLs.  I am xrefing the existing building and the new into the drawing as separate xrefs.  This is so I can move the new building independently of the existing building.  The problem with this project has been finding a good location of 0,0 with the new building that will not get moved later.  The brains and owner are still tweaking to find that “right” balance of “it looks like I spent a lot money but did not”.  Exterior walls are still getting tweaked and the tie-point is coming from one main corner that got tweaked.  Aside from that the xrefs have been great at tweaking things because the building is one entity.
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