Converting a 24x36 Autocad Drawing to 11x17

• #2

I'm trying to understand scales on engineering drawings.

I have a plan view drawing of a proposed electrical room on an 11''x17'' size sheet of paper. If the scale is marked 1/2"=1', is this the scale for the full-size drawing? What size paper is used for full-size drawings? How is the scale adjusted for 11"x17" paper?

If they have marked as scale 1/2 inch equals one foot, then every half inch marked on the paper is supposed to equal 1 foot, or the paper itself covers an area of 22 foot by 34 feet...

• #3

I'm trying to understand scales on engineering drawings.

I have a plan view drawing of a proposed electrical room on an 11''x17'' size sheet of paper. If the scale is marked 1/2"=1', is this the scale for the full-size drawing? What size paper is used for full-size drawings? How is the scale adjusted for 11"x17" paper?

hard to say
the way I do it is find a labelled dimension on the civil or architectual dwg and scale it
some tmes they put a bar graphic scale on the dwg that is say 1" = 8'
if you measure it at 1/2' you are 1" = 16'

ggunn

PE (Electrical), NABCEP certified

• #6

I'm trying to understand scales on engineering drawings.

I have a plan view drawing of a proposed electrical room on an 11''x17'' size sheet of paper. If the scale is marked 1/2"=1', is this the scale for the full-size drawing? What size paper is used for full-size drawings? How is the scale adjusted for 11"x17" paper?

If "full size" means 22" X 34", then 1/4" = 1' at 11" X 17". If it doesn't say what full size means, then you'll have to find something on the drawing that you at least sort of know its dimensions and measure it.

ggunn

PE (Electrical), NABCEP certified

• #10

Typically in civil engineering applications, 1:10 (1″=10′) is used exclusively for detail drawings.

1" = 10' is 1:120 scale, isn't it?

• #11

1" = 10' is 1:120 scale, isn't it?

yes
but they deal in feet
there are 2 scale types
engineers ":' 1:10 (1"=10'), 1:40, etc
architects ":' 1/4 (1/4"= 1'), 1/8, etc

• #12

I'm trying to understand scales on engineering drawings.

I have a plan view drawing of a proposed electrical room on an 11''x17'' size sheet of paper. If the scale is marked 1/2"=1', is this the scale for the full-size drawing? What size paper is used for full-size drawings? How is the scale adjusted for 11"x17" paper?

Unfortunately, the size of the paper has nothing to do with the scale. Are you sure 11x17 is not the original intended size?

It's best not to guess any dimensions from a piece of paper that appears to be a reduced, full-size drawing. You can never tell how much it has been reduced. I recommend you get a copy of the architectural or structural drawing with some dimensions on it. ggunn has the best idea, but only as a last resort.

An engineering firm I know paid an "errors and omissions" charge when a designer tried to interpret the scale of a civil drawing by guessing the width of the parking stalls. The scale was off enough that the lighting calcs were wrong and more lights had to be added.

• #14

Here's what happens when the scales are mis-read.

:lol:
classic

ggunn

PE (Electrical), NABCEP certified

• #16

Yes, that is correct. That portion of my reply is an actual copy and past from an ANSI quotation.

Scaling is very confusing to many. The hardest part is measuring something on a drawing and converting that into real life dimensions. If the Drawing has anything that is dimensioned, carefully measure the dimension leaders then create a Multiplier to get the actual size.

Auto CAD allows the user to import a "Raster Image" (a picture or PDF). If there is something in that picture that is a standard size like a Dollar Bill, a Quarter, or even Coke can, you have a standard for that drawing and measurements can be created. AutoCAD can't Snap to a picture so the user needs to draw a line from one side of the picture object to the other, then an AutoCAD Dimension can be placed.
JimO

But if you can get a pdf with accessible layers and a known scale, you can use the PDF Import feature to bring it into AutoCAD at scale. Also, any drawing that you do over the imported pdf will snap to its features if you want it to.

Imported bitmaps, e.g., rastered images, kinda suck; their features "fuzz up" when you zoom into them.

vierapostencell.blogspot.com

Source: https://forums.mikeholt.com/threads/scale-conversion-engineering-drawings.143736/

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