manage grid spacing and ruler markings

[whistler1]

I'm a newbie struggling with a drawing for a layout plan of my office. Running QCAD 3.21.2 on WIndows 10.
The office is 210 * 410 cm so I'm using a 20:1 scale to fit on A4.
I want to use a grid granularity of 5 cm for snaps - but when I do that the rulers change from 20cm intervals to 25 and the grid dots are only shown every 25 cm.

[andrew]

The office is 210 * 410 cm so I'm using a 20:1 scale to fit on A4.

In CAD, one should always construct real size (1:1). A drawing scale is only applied / needed for printing, as outlined at:
https://qcad.org/tutorial-printing

I want to use a grid granularity of 5 cm for snaps - but when I do that the rulers change from 20cm intervals to 25 and the grid dots are only shown every 25 cm.

By default the grid auto-scales when zooming out to prevent the grid from becoming too dense and displaying as one solid grey area of grid dots.

You can switch off auto scale in the grid preferences if you prefer:
Edit > Application Preferences > Graphics View > Grid > Automatically scale grid

[whistler1]

Thanks for quick response Andrew.
My bad, yes I am working at 1:1 - ie my drawing is "410*210" cm; and scaling 1:20 to make it fit on A4.

Removing the tick on auto scale grid and setting grid spacing to 5cm has given me the grid I need;
and the ruler markings have changed to 1 sub unit every 25cm which because the grid fits that is now OK.
I've attached a screen grab.

Also I've figured out how to use the command box to place rectangles; the issue was finding how to place the relative reference point, and use that with @x,y to draw the shapes.

Thanks again.