Important!

All dimensions should have the same and consistence appearance all over a printed drawing:

Almost all CAD software are built with commands that make it easy to apply a consistent dimension appearance. For this purpose, AutoCAD and other design software use Annotative dimension lines. We only need to configure one Dimension Style. Then all dimensions will have the same appearance at all printing scales.

Use the below are values to set-up annatative dimension styles in AUTOCAD. From the menu chose:
-> Dimension Style Manager -> Standard Style -> Modify. Create a new dimension style and name it ''Dimension 2.5 mm''.

1. Parameters for Tab: Lines

AutoCAD Dimension Style - Lines tab
Set-up Dimension Style - Values for Lines tab

Dimension Lines

Extension Lines 

For correct printing of extension lines (i.e. dashes of 1.4 mm wide with a space of 0.5 mm between dashes the following configuration is need: Format→ Linetype (Use paper space units for scaling...no tick, Global scale factor…0.0002)

2. Parameters for Tab: Symbols and Arrows 

AutoCAD Dimension Style - Symbols and Arrows tab
Set up Dimension Style - Values for Symbols and Arrows tab

Arrowheads

 

3. Parameters for Text 

AutoCAD Dimension Style - Values Text tab
Set-up Dimension Style: Values for Text tab

Text Appearance

Text Placement

   

4. Parameters for Fit

AutoCAD Dimension Style - Values for Fit tab
Set up Dimension Style: Values for Text tab

5. Parameters for Primary Units

AutoCAD Dimension Style - Primary Units tab
Set-up Dimension Style: Primary Units Tab

6. Parameters for Alternative Units

AutoCAD Dimension Style: Alternative Units tab
Set-up Dimension Style: Values for Alternative Units tab

Alternative Units: None set
Tolerances: None

7. Parameters for Tolerances

AutoCAD Dimension Style - Values for Tolerances tab
Set-up Dimension Style - Values for Tolerances tab