I build a custom app for product customizations. I generated a theme app extension which is used for rendering required UI containing input customers use to set width and height. Here’s how it looks for reference Monosnap . I also use product variants which add extra price for final calculations (e.g. variant 1 - default, variant 2 +150$, variant 3 +300$)
I found that there are apps providing this functionality like this one Measurement Price Calculator - Measurement Price Calculator App - Custom Pricing Calculator | Shopify App Store . I need same functionality that calculates price and adds item to cart with correct price