Drawing in MM

I normally draw everything in inches but i have a 2d software that only reads everything in MM. I cant convert everything to a decimal because if the out going software doesn't see exactly the mm number then it will not pull up correct tooling on a cnc. (Example 32mm equals 1.2489xxxxxxxxxx.) Is there any way i can create a drawling in MM just for this program. Thanks

Start your drawing using a metric template usually when you install Autocad there is a second desktop icon that is metric.

There are many DWT's for metric "Architectural metric" "Acadiso" etc

I've never seen AutoCAD automatically place a second desktop icon for metric drawings on a desktop. How is that accomplished during the install process?

i do not have the second icon available as well. Even when i try switching the units, it will measure in mm but still draw everything in inches.

OK...clear something up for me. What program was used to create the drawing and what program are you currently using to edit it?

Ok, ill give you a more detail run down. We are a cabinet shop. I draw all of our custom parts in Auto Cad 2007. I am drawing a flat panel, and inside of the panel i have a ton of holes(perforations) that make up a design on the panel. Approx 8000 per 4' x 4' panel. I am drawing this from start to finish so i have an open page on how i can do this. We have a CNC that cuts all of our parts. The CNC has a drill head with multiple bits that are spaced 32mm apart. When i import a program from CAD, it has to see a perfect 32mm spacing in order to select a multi bit head. If it sees any variation, decimal, rounding of any sort, then it will change to a single drop bit and will drop 8000 times on a panel. What i am wanting to do is to create a program using a perfect 32mm spacing in holes in cad so i can import. Sorry if this is no enough info, i know what i am trying to accomplish but just not sure how to explain or get there. Thanks

Ideally a CAD user starts with the correct template file of which there are two types: imperial (the default) or metric. Examples of each are: acad.dwt (imperial) or acadiso.dwt (metric). I think you started the drawing using the wrong template. What metric sheet size would you be specifying?

OK. I see the two different templates. I have never used the metric template to start. Is there any way to convert a series of holes from the metric template to the inches. The rest of the panel, layout, design etc is on our architecturals in inches so i would have to convert everything over to a completely metric program. Our cnc will cut everything as drawn on the page, doesn't matter metric or imperial. As long as the correct spacing is there, then i can use the different tools. I am definitely closer now that i have a start point with the metric template. Thanks

I never understood the rationale behind mixing units which, by the way, is not the same as specifying distances using alternate units. I'd recommend utilizing the alternate units feature which can be done via the dimension style dialog box (i.e. - Alernate Units tab).

Do you also realize you can specify the precision of your units to as many as eight places?

I write hundreds of programs and have never had an instance where i have had to "mix" the two together before this one. This is one of those instances that i am try to draw in a language per say that our CNC can understand. Technically even the decimal out to eight places is still an rounded number, even by the slightest. A cnc is based on parameters, it either is a certain "command" or inst. Any variance even the slightest will fall as "not" category and change the cnc code. I know its confusing, and im glad i don't have to mess with often

I can't do anything about the precision or lack thereof that will meet your tolerances (i.e. - no rounding). It's built into AutoCAD by the programmers and I don't know of any fix for it.

As far as working in both units at the same time the best I can do is point you to a couple of lisp routines that will do either a metric-to-imperial or imperial-to-metric conversion at the command line. In other words, while your drawing may be set up to use metric units if you wanted to draw an object by way of specifying imperial units (ex. - 4'-4" or 52") the lisp routine would convert the imperial input to metric. Here's the link...

http://www.ellenfinkelstein.com/acadblog/switch-between-imperial-and-metric-measurements/

Or you can draw the object (a panel) to be machined in metric then insert this drawing into a drawing done in imperial units of the cabinet the panel will be installed in.

EXCELLENT!! I think i can get that to work because technically that is still using true numbers but more in an equation form. Thank you for the help...I didn't know if i would be able to explain into something someone would understand.

Believe me when I say I did not understand much of what you said. Any response that ultimately works is purely accidental on my part and in no way makes me smarter than you.

Good luck in your endeavor.

Remark re multiple desktop icons, it may just be Civ3D but we end up with 2 icons Metric & Imperial. If you do a custom install you can turn of lots of stuff and the metric & imperial icons is just one of those, here in AUS we may have a different build than perhaps US where the metric is turned off.

I did this lisp that works for hor & vert entry L R U D could add a ft/mm factor as part of it, now where did I put it. Similar to Remarks suggestion, type L44 means go left 44" but can add the conversion factor may need one of the rounding functions also so always get a whole mm answer.

Graderbird2004 make a copy of your desktop icon.

My Civ3d imperial icon properties "C:\Program Files\Autodesk\AutoCAD Civil 3D 2013\acad.exe" /ld "C:\Program Files\Autodesk\AutoCAD Civil 3D 2013\AecBase.dbx" /p ">"

Change on yours the end to /p "Acadiso" and save, edit title to METRIC.

It was here at cadtutor, LUDR draw a line in the 4 normal directions. Graderbird2004 it can be amended to convert imperial to metric I need to know will it be feet and inches or just inches much easier. Or will there be fractions 1/8" ? Post a dwg.

; draw a pline by direction Up Down left or Right use upper or lowercase
; by Alan H Dec 2015
; this version is a metric/decimal version
; version 2 depending on requests will be a imperial version
; 1'8 1/4" input d1.8.25 start with 1.8 = 1'8" then add second fraction ver 3

; how to use u123.45
; L34.57 
; d102.6 
; r53 
; C or <Cr> to leave open any amount of legs.

(defun ah:left ( / pt2)
(setq pt2 (polar pt pi (atof (substr ans 2 (- (strlen ans) 1)))))
(setq pt pt2)
(command pt2)
)

(defun ah:up ( / pt2)
(setq pt2 (polar pt (/ pi 2.0) (atof (substr ans 2 (- (strlen ans) 1)))))
(setq pt pt2)
(command pt2)
)

(defun ah:right ( / pt2)
(setq pt2 (polar pt 0.0 (atof (substr ans 2 (- (strlen ans) 1)))))
(setq pt pt2)
(command pt2)
)

(defun ah:down ( / pt2)
(setq pt2 (polar pt (* 1.5 pi) (atof (substr ans 2 (- (strlen ans) 1)))))
(setq pt pt2)
(command pt2)
)

(defun C:LUDR ( / pt ans)

(command "_pline")
(command (setq pt (getpoint "Pick start point - Enter or C to finish")))
(while (= (getvar "cmdactive") 1 ) 
(setq ans (getstring "Enter L123 U456 R67 D78 "))
(cond ((= ans "")(command ""))
     ((= "L"(strcase (substr ans 1 1)))(ah:left))
     ((= "U"(strcase (substr ans 1 1)))(ah:up))
     ((= "D"(strcase (substr ans 1 1)))(ah:down))
     ((= "R"(strcase (substr ans 1 1)))(ah:right))
     ((= "C"(strcase (substr ans 1 1)))(command "close"))
) ;cond
) ; while
(princ)
)

The UNITS command does not change your drawing units. It only changes the length measurement units. You will still draw a line 12 (inches) units long, but Autocad will measure it as 304.80 millimeters.

There is another completely different command for changing the basic drawing units. In other words, the command -DWGUNITS will change your whole dwg file to a metric dwg file, even if you have already completed it in feet and inches.

It may be possible to just draw the cabinet panels in inches, using the imperial template, and then make use of the command -DWGUNITS to convert the whole thing to millimeters in one shot. Then do a Save As "my metric drawing".dwg so your original imperial drawing will be kept. The leading "-" is required, and it is a four or five step command, including re-scaling the entire drawing to the new metric units.

Open a text window (F2) and then just type -dwgunits, pick your new units (mm) and precision level, and answer Yes to a couple of questions about insert units and whether you want to re-scale the entire contents of your drawing. By the way, even after you do this you can still use your existing imperial paperspace layouts, but you will probably have to adjust the viewport scales.

I am not sure -dwgunits adjusts the viewports but i'll bet they end up they are not quite perfectly scaled. -dwgunits does not however, change your printer and paper parameters.

32mm= 1.25984 inches, by the way. but them you knew that.

Not knowing what your project parameters are I might guess that using an ARRAY of holes with 'n' number of rows and 'n' number of columns, each spaced at 1.2598" apart could get some of it done.

I thought about this a bit. Unfortunately, Autocad can't get more accurate than 8 decimal places even in model space (Format Tab>Drawing Units). This helps explain why the threshold for dimensioning is also out to 8 decimal places with the imperial scheme.

Which, granted, is pretty darn accurate.

I guess in this case your options are convert to imperial with a certain degree of acceptable tolerance or somehow update the CNC software to accept the original metric units for this one job (if those tolerances are more accurate than the conversion). I would not want your job sir! LOL.

-ChriS

Ok, ill give you a more detail run down. We are a cabinet shop. I draw all of our custom parts in Auto Cad 2007. I am drawing a flat panel, and inside of the panel i have a ton of holes(perforations) that make up a design on the panel. Approx 8000 per 4' x 4' panel. I am drawing this from start to finish so i have an open page on how i can do this. We have a CNC that cuts all of our parts. The CNC has a drill head with multiple bits that are spaced 32mm apart. When i import a program from CAD, it has to see a perfect 32mm spacing in order to select a multi bit head. If it sees any variation, decimal, rounding of any sort, then it will change to a single drop bit and will drop 8000 times on a panel. What i am wanting to do is to create a program using a perfect 32mm spacing in holes in cad so i can import. Sorry if this is no enough info, i know what i am trying to accomplish but just not sure how to explain or get there. Thanks

What I am confused about is the spacing. You never said what size hole just that they are 32mm apart is that from edge to edge or center to center because it sounds like the hole are different sizes.

I am just curious to if this trick will work

1- Make sure you are using a metric template

2- Use command "DSettings" and go to Snap and Grid tab

3- Set both X and Y spacing to an integer number (in your case 32)

4- set snap and grid to ON

5- Draw a circle using the grid

6- Copy multiple the circle in X and Y direction

I may be wrong but since you are using the grid, AutoCAD is forced to work with your Grid spacing which is an integer number

Adsk