Welcome Will… I will speak as someone who has been in the theatre and costume business for 42 years (until a fire destroyed our shop a couple months ago.)
While we aquired an Optitex system second hand, it did not include the “made to measure” module - which was another ridiculous cost. Much of my job making patterns was producing patterns to custom sizes… which led me to find Valentina, the precursor to Seamly2D. With my programming abilities the V application would fill my needs quite nicely. For awhile after the fork, I worked on developing the app myself, and then a bit later decided to apply that to Seamly.
Besides being open source, and not costing an arm and a leg… the real power of Seamly2D lies in the “made to order” aspect - where 1 draft will automatically resize based on the measurement file applied. While the measurements are geared towards the human body and garments, there is nothing that precludes using the app for other industries. For example… you could easily create a cushion pattern that produces the pieces say based on the width, length, and height - which could be provided by a measurement file or through custom variables (which are contained in the pattern file itself). Although my original background in Civil Engineering also includes nearly 50 years of drafting, I can’t say whether Seamly2D would fit your needs any better than some other apps?
I would need to know more of your workflow… like do you need to have a pattern adjust sizes? Or are you looking to be able to trace or reproduce existing pattern pieces?