If you wish to embroider, say, 3 meters of fabric to create a shawl, do you still need to make sure the fabric is on grain?
Or do you only check for fabric grain if you will cut for sewing projects?
I know the weave of the cloth makes a very big difference.
I am a weaver and have seen professional looms in action. Grain, as I understand, is the Warp + Weft in threads per square mm, or inch.
The grain is a living part of a fabric. I would take that into accord, but I've not done a lot of "fine embrodery". It is just logical.