How to convert CAD drawing from metrics to inches

[Anonymous]

Greeting

Need help with converting the drawing from metrics to inches, and once drawing is completed - back from inches to metrics.

Thanks, Anthony 

[Patchy]

Use:

-DWGUNITS and choose YES to scale.

[Anonymous]

Appreciated your help but after converted as mentioned, I copied / pasted in the drawing (inches setting) - the drawing didn't scale to the inches setting, further assistant, please.

Thanks, Anthony

[john.vellek]

Hi @Anonymous,

-dwguinits or units will change the units in your drawing but they won't fix the scale discrepancy. To get everything to inches from metric, you will need to turn everything on, thaw everything and then unlock everything. Now you can scale the centimeter or millimeter based drawing by using SCALE. Then you will need to adjust your dimension and text styles accordingly. 

Alternatively, you could simply XREF the file into a new master and scale it to the proper size. 

Or, you can add your dimensions and dispaly alternate units - does this work for your project?

Please let me know if this makes sense or if you need additional help or resources.

Please select the Accept as Solution button if my post solves your issue or answers your question.

[Anonymous]

Thank you John.

Can you help provide step by step on the "scale process" and or "turn everything on"?

[john.vellek]

HI @Anonymous,

I can do this step-by-step if you like but I found a video that might work better? Please let me know and I will jump back in if you like. You can also attach a sample drawing if you would like me to take a look.

[scot-65]

No need to scale anything.

Background:

We had a client that required PDF's that show Metric units and we use Imperial.

Needed some way to be able to keep editing in Imperial, yet transmit showing in Metric.

What you will be changing a few dimension style variables, then applying to existing dimension objects.

Command -DIMSTYLE "Apply" and select everything (notice the hyphen "-" prefix in the command name).

You can set these variables as temporary overrides (by entering at the command prompt) or

apply these settings and saving the current dimension style.

Have a look (I have posted this panel quite a few times over the years...)

As you can see, there are four dimension variables to adjust. That's it.

And Welcome to these Forums.

[Alfred.NESWADBA]

Hi,

@john.vellek

>> -dwguinits or units will change the units in your drawing but they won't fix the scale discrepancy.

Really?

I'm more with @Patchy

- alfred -

[john.vellek]

Hi @Alfred.NESWADBA,

Perhaps I am not understanding the question, but since AutoCAD works on a unit basis and doesn't really know what a cm or inch is I don't (IMHO) think that just changing units works the way the OP wants.

I made a Screencast to illustrate my understanding of this issue. I show that when I have imperial units configured in my dwg, I draw a 12 unit (1 foot) long line. Then I change the units to CM. now the line measures something different than 12 units.

Here is an article that also hopefully helps to explain my point of view.

Also, merely switching dimensions factors works only if you are dimensioning existing objects. Drawing new objects in a different units configuration can be a real pain.

[Anonymous]

@john.vellek

attached is equipment in metrics and like convert into inches and copy / paste into inches CAD file.  Appreciated your help.

[john.vellek]

Hi @Anonymous,

Does this work for you? I scaled all the contents by 0.0393701

Please select the Accept as Solution button if my post solves your issue or answers your question.

[Anonymous]

sorry - didn't work....when insert or copy over to the building drawing, scale is not correct.  See attached.

[john.vellek]

HI @Anonymous,

I disagree! When I inserted the file I sent you it comes in correctly. Take a look in the upper right corner. I think this the correct size.

Let me know if this is wrong and we can try something else.

[Anonymous]

you're correct, sorry.   Can you provide the step by step to you convert this?

Thanks a million!

[john.vellek · Accepted solution]

Hi @Anonymous,

Sure thing!

You had already changed the units to inches using -dwgunits/units so all that was left was to scale.

II checked to make sure that everything was turned on, thawed, and unlocked. Then I used SCALE, selected everything and applied the scale factor of 0.0393701

Please select the Accept as Solution button if my post solves your issue or answers your question.

[Anonymous · Accepted solution]

thank you and how did you arrived with scale factor at 0.0393701?  2nd - if to scale drawing back to Metric (?), what is scale factor. 

[john.vellek · Accepted solution]

Hi @Anonymous,

That is the easiest part of all of this - an online calculator 🙂

Please select the Accept as Solution button if my post solves your issue or answers your question.

[Alfred.NESWADBA]

Hi,

>> I show that when I have imperial units configured in my dwg, I draw a 12 unit (1 foot) long line.

>> Then I change the units to CM. now the line measures something different than 12 units.

Exactly, because 12 inch is not equal to 12cm, that's why you get a different value. At least the -DWGUNITS command can do that scale without needing to start scale, or using insertions from one drawing with units-setting 1 to another drawing with units-setting 2. All done in one step.

BTW: you don't need to know the scale factors between different units.

And even better: you don't loose accuracy because you can't type in the conversion factors to all decimal places 😉

- alfred -

[john.vellek]

Hi @Alfred.NESWADBA,

I guess I have had it do screwy things so many times in the past (no doubt user error) that I quit using it for the longest time. I will have to re investigate the scale option in dwgunits to update my attitude.

Thanks as always for the contribution.

[RobDraw]

Patchy nailed it in the first response.