topic Re: Converting a drawing done in mm to inches in AutoCAD for Mac Forum

Converting a drawing done in mm to inches

Anonymous — Wed, 28 Aug 2013 00:17:06 GMT

Forgive my ignorance...I'm a Cinematographer/Editor who has a background in hands-on custom fabrication (not in a digital sense*) and recently built a product that now needs to be drawn up in CAD for producing a CNC example.

First off, I have not had professional training in AutoCAD and have watched hours of tutorials that in some cases..led to more confusion because of the Windows to Mac translation (or loss of it*). Regardless of the lack of Mac oriented AutoCAD tutorials..I have found my way to becoming fairly proficient in drawing up designs (again, not professing to be an expert or anywhere near but I know how to draw and think in 3 dimensions).

As a result, I have a drawing that is fairly close to final and for the sake of being precise...was drawn in Millimeters/Centimeters... (excuse my ignorance) the reason I'm unsure is because the Mac version isn't as user-friendly as the Windows version..I drew it up in Centimeters (all my measurements/lines were input as .9 for a 9mm measurement). However, I want to make sure I was in fact dealing with .9 centimeters rather than .9 millimeters.

That said, I'm trying to figure that out because the CNC machinist asked for it in imperial/inches and after exploring and reading countless articles in the user forums and elsewhere online... I'm still unsure of the correct way to remedy my problem. As an if-all-else-fails precaution, I've printed various views of the product and drawn out dimension lines and references to a key with all the measurements shown in millimeters as well as in inches. Any help is greatly appreciated!

Again, I don't pretend to be an expert in AutoCAD and am very open to any advise given.

Thank you for your time,

Phil

Re: Converting a drawing done in mm to inches

Anonymous — Wed, 28 Aug 2013 00:51:05 GMT

Here's another attachment screenshot of some of the drawing to illustrate the amount of adjusting to be done if needed.

Re: Converting a drawing done in mm to inches

maxim_k — Wed, 28 Aug 2013 03:54:46 GMT

Welcome to the Autodesk Forums!

Hi Phil,

If you are finally sure that 1 AutoCAD unit in your drawing equals 1 cm (10 mm) than in order to convert the whole drawing to imperial units (1 AutoCAD unit = 1 inch) you need to scale everything in the drawing with scale factor 1/25.4=0,03937007874016

In order to accomplish this with more precision you have to call SCALE command, pick base point for scaling (anywhere in the drawing), then call geometric calculator 'CAL (yes CAL with apostrophe in front of it), than enter 1/25.4 and hit Return:

Command: SCALE <- hit Return
Select objects: <- Select objects

Specify opposite corner: 2 found
Select objects:   <- hit Return
Specify base point:    <- Pick base point
Specify scale factor or [Copy/Reference]: 'CAL   <-Type 'CAL command and hit Return
>>>> Expression: 1/25.4   <-Enter this expression and hit Return
Resuming SCALE command.
Specify scale factor or [Copy/Reference]: 0.039370078740157

Now 1 AutoCAD unit = 1 inch.

Maxim

Re: Converting a drawing done in mm to inches

Anonymous — Sun, 28 May 2017 15:50:44 GMT

And from whence would said command be entered?

Re: Converting a drawing done in mm to inches

maxim_k — Sun, 28 May 2017 17:13:00 GMT

Hi Donald,

You can type command on keyboard, or use:
- Tool Set palette: Drafting tab > Modify panel > Scale
- Menu: Modify > Scale

http://help.autodesk.com/view/ACDMAC/2017/ENU/index.html?guid=GUID-E74220CD-3FB3-419D-AB9E-4B29B87DEA5C

Maxim

Re: Converting a drawing done in mm to inches

Emmsleys — Sat, 03 Jun 2017 04:21:08 GMT

Following up on your thread, it appears that several folks have tried to help on this issue.

Did any of the posts in the thread help with your issue?

Please post back in the thread if you are still having an issue with AutoCAD or Select Accept as Solution for the post’s that helped.

Thanks for your time.

Re: Converting a drawing done in mm to inches

krystianwiatr — Mon, 14 Oct 2019 14:11:52 GMT

Thank you, maxim_k!

'CAL is what I was looking for, all those years, but was too lazy to look it up. I was spoiled by using primarily Inventor, which have formula capability built in to any command, which you would think they would have in acad by now.

As for the units conversion, I think 1"=2.54cm (25.4mm) , so I would shift decimal by one for cm to in conversion.

Thank you,

Krystian