3ddd is not responsible for this extension. All risks associated with the use of this extension are borne by the users.

Video about the script:
https://youtube.com/shorts/PxU-ZmiLBF0?feature=share 
https://vk.ru/clip-226908262_456239117 

Script for scaling objects to exact sizes. Shows the area of all selected polygons and the dimensions of the selection (including the distance between two selected points, polygons, etc.)

Other scripts: https://3dsky.org/collection/shared/5514167 

Installation:
Drag the script into the open 3ds Max window.
Next: Customize - Customize User Interface - Toolbars, category sofiakholina.
Drag ScaleBySize to any panel.

If the script does not work correctly or you encounter an error — please report it.

How to use:

Current Size - size of the selection; area of selected polygons in scene units and in the line below in m2.
Get Size From Selection - transfer the current size to the fields X, Y, Z.
X, Y, Z - size along the axes; one field - proportional scale.
XYZ - equal size along all axes.
Keep bottom - the bottom point remains in place.
Scale individually - each object gets the size separately when multiple objects are selected.
Scale - apply.
Pick 2 Points - specify two points in the viewport.
Length / Match Scale - make the distance between the points equal to Length.
Reset XForm after scale - apply Reset XForm after scaling.
Clear - clear all fields.

Fields accept percentages (150% - one and a half times larger).
Each press - one step Ctrl+Z.

Designed for 3ds Max 2014 and newer. The icon on the panel - from 3ds Max 2017, in earlier versions the button is labeled with text.