Ecomtl is for the material records of a checked out revision. There is probably no ecomtl view in method tracker, since method tracker is for viewing any revision. You have to see which views are actually in that application, most likely partmtl.
Thank you so much Alisa, I checked PartMtl but it doesn’t exist as a standalone view, there’s a EngMethodTree.PartMtl but the AltMaterial_c doesn’t exist there either
EcoMtl, JobMtl, and PartMtl are all separate tables. If you add a field to one, and you want it to flow through, you have to add the field on all of them and then set up UD column mapping so that it copies from EcoMtl to PartMtl when you check the revision in, and from PartMtl To JobMtl when you engineer the job.