I am pleased to share with all of you a brand new Ldraw-based digital designer for iPad that I have spent many hours over the past few years on!
Masonry is a 3D brick creation app with access to Ldraw's 5000 part library and it supports freeform editing and step creation.
I've got a video of it in action, and you can see more details at my website: https://masonryapp.com
Thanks!