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Thread: Drawing scale factors 1:1 or 1:12

  1. #1
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    Default Drawing scale factors 1:1 or 1:12

    The office i work in has this method of dealing with plans and details that usually results in a drawing being 1/12 of its true dimensions. I believe its because they set it up in decimal units, and type in 1 for 1 foot or 2.25 for 2'-3".
    however i prefer in working with architectural units so i change the drawing units, this causes everything drawn at "10" to actually measure out to 10 inches. so now all of a sudden im scaling down every dimension i type in by 12. This seems to create more problems when it comes to setting the viewport scales.

    i dont see why you would want a drawing set up in ANYTHING other than 1:1 scale, even if that does cause details to be tiny compared to the site plan.

    They refer to it as having a drawing "set up in either Feet or Inches" depending on whether its a full site plan or just details. im thinking about recommending we stop doing this but has anyone else ever heard of working this way? If you have would explain the advantage or just the idea behind it.


    so after talking more about it with others, i understand a little more-

    Our surveys get brought in at a scale- that when measured in Architectural units- is at 1/12 scale, so 100 feet in the survey reads as 100 inches when in architectural units.
    i said why not just scale the survey up by 12 when we bring it in, they said this screws the coordinates and makes it completely off the coordinate system.

    so when i draw details in the same drawing using architectural units, it draws everything 12 times the size.

    is this how everyone deals with surveys and site plans??
    Last edited by JRBOURNE371659; 2009-09-10 at 05:41 PM.

  2. #2
    All AUGI, all the time TerribleTim's Avatar
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    Default Re: Drawing scale factors 1:1 or 1:12

    Sounds like you are talking about two different things. The drawing is still drawn 1:1. It's the definition of what "1" is that is different. Civil generally draws in decimal units, meaning it is 1/12 of the architectural units. That's pretty common, I run across it on pretty much every project here. I guess all them guys "across the pond" using metric are doing the same thing, right? The real questions are, what are you trying to draw? What's the industry standards for that type of drawing?

    ******EDIT*******To answer your edit*******

    what I do is take my Civil site plan that is drawn at 1:1 using decimal units and xref it into my Architectural site plan and then scale the xref by 12. Then it doesn't mess anything up on their end because the xref is still 1:1 in decimal units when I give it to someone else. Plus, if Civil sends me a new drawing, I can simply slide it in in place of the previous version and I'm good to go.
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    Default Re: Drawing scale factors 1:1 or 1:12

    My issue was just that i was editing details that were drawn at the same scale as the survey/site plan, one of the details needed a new viewport. Thats when i realized none of the viewport scales were relevant because my detail was scaled down by 12.

    Its an Engineering firm, site plans, details and sections.
    Everything we do is in feet and inches, so for me its easier to set the units to architectural, or i thought it was.

    I just want surveys to come in on the right coordinates, in true scale, in architectural units.
    I keep feeling like there is some practical reason for it being the way it is that i don't understand yet.

  4. #4
    Certified AUGI Addict jaberwok's Avatar
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    Default Re: Drawing scale factors 1:1 or 1:12

    If everybody else is working in feet (logical or not) and you are working in inches then you are the problem unless and until you can persuade management to change everybody else to your method.
    I'd guess that you have a good argument for change but will the people who matter agree?
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    Certifiable AUGI Addict cadtag's Avatar
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    Default Re: Drawing scale factors 1:1 or 1:12

    Quote Originally Posted by JRBOURNE View Post
    I just want surveys to come in on the right coordinates, in true scale, in architectural units.
    I keep feeling like there is some practical reason for it being the way it is that i don't understand yet.
    Now this is something that's not even possible in CAD. The civil coordinates are going to be in a coordinate system -- if your surveyor is worth his salt it will be a State Plane coordinate system and zone (for US locales, other countries will have something similar, based on the geometric shape of the earth -- see mapping and cartography for more depth)

    That coordinate system will be in either feet or meters, not inches. There is not coordinate system that maps the planet to inches. You can reference the civil information into a detail drawing, and scale up by 12 to measure the distances in inches, but the coordinates will never be right, because you've now multiplied every northing and easting by 12.
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