Help, need Easy Formula :)

How to write a formula for SketchUp correctly, I want an attribute:
= sum (Area.Group1 + Area.Group2 + Area.Group3)

. Template
… Project
… Component
… … Area.Group1
… … Area.Group2
… … Area.Group3

Format: 2D
We work tools: Pencil
Task: Get the sum of the sizes of all lines inside the component, and we also draw in different groups :slight_smile:

You use the facearea formula, plus wise to have a scaler to force the redraw if scaling. If you intend to alter the raw geometry then you need to do a redraw anyway.
Can you post a file of the objects and description of the intention, workflow
inches or metric?