How to provide drawing scale

Is there a way to select a drawing scale? I have tried the menu Options, Current Drawing Preferences but that only resizes the dimension text. I drafted a glider, supposed be full size, for people, but the dimensions are not what I want.  I'm trying to use a drawing scale of 1:50, units of mm on A4 paper - 8 1/2 by 11 inches . The glider is 5000 mm long or 5 m.

hm... not sure I understand.

Drawing is performed in model space scaling - which is 1:1.

Printing may be performed with pint scale - yet it's different thing, it defines how to scale the drawing area to fit it to print area.

For dimensions, it's possible to scale apply scales too - one will affect the sizes of dimension's elements, another one will affect the value in dimension (i.e 10 mm in drawing might be shown, say, as 20 mm in dimension text).  But they are different indeed.

So basically there is not such generic notion as drawing scale (like, I suppose, supported in ArchiCAD).

Just draw in 1:1 and later scale it on print preview. That's it, I suppose...

LibreCAD can adjust the size of the dimension numbers. But how about a scale of 1:50 like my glider drawing?  That is, 1 unit, I chose mm, to be 50 mm.  Archicad is commercial. I'm trying to discuss mechanical engineering drafting with CAD, in this case LibreCAD.  Do I need another cad drawing software?

well, if I understand you correctly, there are several apparoches:

1) you draw coordinates in 1:50, and change the scale on dimension (so in dimensioninign, 1 will be 50).

2) if you originally draw in 1:1 and need to scale your drawing to 50 (or vise versa) - you need to select your drawing and scale to 50 using Modify -> Scale command.

3) If you need to print - you select scale for printing to fit your drawing to paper....

Sorry, yet I feel that I don't understand what goal you try to achive and where and why do you need such scaling.

Why can't you draw in actual dimensions? I.e use coordinates of points as they actually are in 1:1?

I'm using the scale of 1:1 for mm.  My drafting of my glider is supposed to be life size.
From your hints, I try,
A) Tools
B) Modify
C) Properties
D) select the object (dimension)
E) enter the new label for the dimension
F) press enter

I'm using LibreCAD 2.2
This will change the number for a dimension.

oh, so it seems you'd like just to change value on dimension, right? If it is so, you need to use dim scale.

for 2.2 - it should set in options->drawing preferences->dimensions.

If 2.2.2-alpha - (https://github.com/LibreCAD/LibreCAD/releases/tag/2.2.2_alpha-latest) this is controlled by parameter "Linear Scale" for dimension style, that is used by particular dimension (or in default dimensions style, of course).  

That factor is just to re-calculate measure dimension label, so if in drawing 1:1 you have 10 and scale is 5 - in the dimension, 50 will be shown.

All discussed ways will lead to the same result.


But changing dimension numbers manually is the worst idea I think. If there are any imperfections in the drawing the numbers will still be correct, but the drawing is useless for further use.

So drawing 1:50 to fit printing dimensions is ok but error prone. You can make mistakes in calculating 1:50 length and coordinates. Setting the Length Factor in Current Drawing Preferences to 50 will create the correct numbers in dimensions.

Thus the recommended way is to set correct Unit in Current Drawing Preferences and create the drawing 1:1, no errors in number scaling. Then use an appropriate factor for printing, depending on paper size.

See:
https://docs.librecad.org/en/2.2.0_a/ref/fundamentals.html
https://docs.librecad.org/en/2.2.0_a/guides/annotate.html

Thank you for all your help!
The Length factor in the Dimension tab was what I did not realize what it was - I was looking for scale something or other.

I have found another difference for LibreCAD for units for dimensions.  From Options menu, choose Drawing Preferences, then the Dimensions tab, not the Units tab.  For example, I want mm measurement and no trailing zeros, so I choose Decimal for Linear units and 0, zero, for Linear Precision.

The Units tab selects mm, a foot, etc.

This produces, what I think, is a more readable drawing.  I couldn't have done all of that without help from people at this Forum!