# Thread: Metric vs Imperial question

1. ## Metric vs Imperial question

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I'm new to autocad and came from Metric system country. now I have hard time switching to Imperial system. and I hop you can help me answering some questions please.
1- is there any comparative scale factor between metric and imperial? for instance 1:20, 1:50, 1:250 and so on, compare to what in imperial?.

2 - in the unit dialogue box, if i use metric i only can choose Decimal not any other options like Architectural , engineering..etc. right?

3- if I want to draw in cm or m not millimeter I mean input my distance in cm or m while drawing how to do it?

4- if I want to open a metric drawing in a imperial model space how to switch from M to inch. Thanks

2. Do yourself a favor and avoid mixing the two systems if you possible can.

If you ignore that advice you might want to become familiar with scaling factors like metric to imperial and imperial to metric. And buy yourself a big bottle of Advil or Excedrin too.

3. Metric plot scales are as follows (with roughly equivalent Imperial plot scales in parentheses):

1:1 (Full Size)
1:2 (Half Size)
1:5 (3"= 1'-0")
1:10 (1 1/2"=1'-0")
1:20 (3/4"=1'-0")
1:25 (1/2"=1'-0")
1:50 (1/4"=1'-0")
1:100 (1/8"=1'-0")
1:200 (1/16"=1'-0")
1:250 (1"=20'-0")
1:500 (1"=40'-0")
1:1000 (1"=80'-0")

Standard metric drawing sheet sizes in millimeters are as follows:

A4: 297x210 (11.7"x8.3")
A3: 420x297 (16.5"x11.7")
A2: 594x420 (23.4"x16.5")
A1: 841x594 (33.1"x23.4")
A0: 1189x841 (46.8"x33.1")

4. Thank you so much ReMark for the help. the scale factor you give is what i was looking for..Advil bottle works too LOL

5. Originally Posted by jak ali
I'm new to autocad and came from Metric system country. now I have hard time switching to Imperial system. and I hop you can help me answering some questions please.
1- is there any comparative scale factor between metric and imperial? for instance 1:20, 1:50, 1:250 and so on, compare to what in imperial?.

2 - in the unit dialogue box, if i use metric i only can choose Decimal not any other options like Architectural , engineering..etc. right?

3- if I want to draw in cm or m not millimeter I mean input my distance in cm or m while drawing how to do it?

4- if I want to open a metric drawing in a imperial model space how to switch from M to inch. Thanks

1) This one was answered already, but remember that the title block will be drawn in mm, so the scale factor only makes sense if the model space objects are drawn as mm, if drawn as cm or m then do the math for the difference.

2) Decimal is your only choice.

3) AutoCAD just sees a unit of 1, so if you decide to draw in cm in a drawing then you stick with that and enter all values as cm.

4) It is best to stay with the original system but if you must convert the drawing one way is -dwgunits (I got that one from reMark recently.)

6. Get familiar with using -DWGUNITS (include the -).

7. Originally Posted by SLW210
Get familiar with using -DWGUNITS (include the -).
^^^ This

Basically AutoCAD doesn't know what an inch or a millimeter is. So if you draw something that is 1 unit (inch) in length on your imperial drawing and you then import it to my drawing where and inch is 25.4 units (millimeteres) long, then your inch will be 25.4 times smaller than mine (PWNED). So you will have to scale yours up by a factor of x25.4 or mine down by a factor of or 1/25.4 to make them match.

Among other things this is conclusive proof that although millimeteres are 25.4 times smaller than inches, they are actually 25.4 times better.

8. If they are so good why do metric users have so many problems using them?

9. Originally Posted by ReMark
If they are so good why do metric users have so many problems using them?
It is because AutoCAD was written for the Imperial system, and has its troubles adapting to the Metric system.

There do seem to be a fair number of posts about feet, inches, decimal feet, engineers units, architects units, surveyors angles, etc., etc. but you probably gloss over them.

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I don't think I gloss over them intentionally at least. What strikes me is metric users unable to decide what one unit is going to represent in model space then getting totally perplexed once they get to a paper space layout and viewport looking for an output at a scale that makes sense.

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