With Free Zoom OFF, when you zoom using Page Up/Down or using your left mouse button to set a zoom area window, Datacad will zoom your view to the nearest Display Scale set in the drawing (Utility Menu, F0 Settings, F4 Edit Definitions, F1 Scales).
With Free Zoom ON, it reveals the F5 Percent option. For this example, let's set F5 Percent to 100.
So if you have F4 Free Zoom ON and F5 Percent 100, when you set a zoom area window, it will fit your zoom area to fit withing the very outmost boundary of your drawing board area. You can see the calculated value for the custom free zoom display scale show up in the Display Scale drop down of the Status Panel after a Free Zoom. It will be displayed using the decimal form of the display scale, (example: the decimal form of 1/4" = 1'-0" would show as .02083333).
So with F5 Percent set to 100%, it can put entities you may want to select right at the boundary of your drawing board, making them hard to select or see. So setting F5 Percent to a value less than 100% will add a bit of margin around your Free Zoom area essentially extending your zoom area and fitting that to your drawing board display area. A Percent value between 90-99% seems to be what people tend to use. I keep mine at set at 98% I am guessing you might have a low value in F5 Percent causing a large margin area around your zoom selection.
A little more on zooming. If you mouse scroll to zoom, I have no idea what it uses to calculate the zoom values but they just keep going and going which I like!
Legend has it, that the idea of relating the actual display of the plans on screen at scale was done so people could use an actual physical scale to scale things on their monitors or for those OG lead slingers, have it visually close to what they were used to seeing on paper at common scales. In my 26 years of using Datacad I have only seen one other person scale off their monitor, but hey they could!
Thankfully it was a CRT monitor. Keep those pointy scales away from my LED panels!
Hope this helps. Let us all know if you work things out.
