Model Space vs Viewport scale

Am trying to use millimeters for the first time. In model space, I set UNITS to millimeters. I draw a 5 unit line. No problem. I go to a layout tab and the viewport shows a 5" line, using a 1:1 scale. How do I make the viewport show a true 5mm line? What am I missing? If I choose inches as my units, the viewport scale is true 1:1 scale

What units did you set to mm? You need to set length in UNITS to decimal.

How are you measuring the line?

Firstly draw a title block in a layout at 1:1 scale in mm A4 A3 A1 etc zoom extents then have a mview window within it then check your scale again. If you dont have the mview window the correct size then it will be very hard to work out whats going on with scale.

Can you post the file?

Objects are drawn in AutoCad drawing units.

5 drawing units = 5 inches = 5 mm.

To get it to draw a true 5mm line

Using a ruler make a line on your monitor with a sharpie and create a line the same distance is about the only way.

Notice when you set 'units' you are setting insertion scale.

You have to scale between different measurements

If you draw a line 2.54 units long with insertion scale set cm then changing it inches just makes it report the line is 2.54 inches.

What that setting is for when you enter Block command and create a block notice the Block Unit combo box at bottom left.

So it is set to what your current settings is say inches.

When you insert notice bottom right where is says Factor.

If you change the insertion scale 'units' to cm then it change from 1 to 2.54.

Couple other notes

Select a viewport and on the properties pallete notice the standard scale and annotative scale and make sure you know the difference.

If you use the DI(distance command) in paper space and you are not inside the viewport it still gives model space length.

So if you create a line in model space 10 units long, then go to paperspace and set the viewport to 1:2 then use distance command it reads 10.

You can draw a line in paperspace the same length and it will report 5 and again this is in paperspace and not double clicking inside the viewport

 

To get it to draw a true 5mm line

Using a ruler make a line on your monitor with a sharpie and create a line the same distance is about the only way.

 

What??? ...

Was just trying to emphasize the point that AutoCAD uses Drawing units and does not represent 'units' as centimeters, inches, etc......

What??? ...

Then use white-out to erase it when you're done.

Then go buy a new monitor and do what SLW wrote.