How do I slide a wall exactly in SH3D Windows?

[iTwo]

How can I best slide a wall to make a room smaller or bigger?

If I click on Windows, then hold shift, the wall will slide in one axis. But any little jitter on the mouse prior to holding shift and the wall will be off.

[Keet]

There are several ways. What I mostly use:
1. Select a wall and move it with the cursor keys. The size of movement depends on the zoom level. Fully zoomed in it's 1mm per key press, the smallest possible in Sweet Home 3D. I don't know what the value is if you have your system set to imperial.
2. change the X/Y location coordinates of the start and end points of the wall in the Modify Wall dialog.
3. Use the move function of the advanced edit plugin. Select the wall and in the move dialog set the value to move. It will immediately show in the plan and if you cancel it it will revert to the original position.

Method 2 can set a precise position. Method 3 can move with precision counting from the start position.

[iTwo]

The advanced edit plugin appears to be from 2016. Would it still work?

https://sourceforge.net/p/sweethome3d/plug-ins/4/

[iTwo]

If I drag a window or door, I get little hints as to the relative position. Is it possible for plugin to extend those little blue hints to wall movements?

[Keet]

The advanced edit plugin appears to be from 2016. Would it still work?

Yep, still good and a must-have. It really should be part of Sweet Home 3D itself.

The easiest way is to first install the Plugin Manager plugin. That plugin makes it easy to select and install other plugins and alerts when there are updates.

[Keet]

If I drag a window or door, I get little hints as to the relative position. Is it possible for plugin to extend those little blue hints to wall movements?

Nope, you have to calculate this yourself. Unfortunately this is an example where using the imperial system doesn't make it any easier. With the decimal system it's pretty straightforward with any dimension, using the imperial system is only easy with 'easy' dimensions.
The number fields are little 'calculators': you can enter a formula. For example (5.5/2)+1 is resolved and the result is set as the number. I don't know how well that works with the imperial system.

[Puybaret]

Formulas work too in imperial system. You can enter 1/8+2 1/8 to get 2¼".