Hi,

I import a detail attribute using sop import lop.
I notice that there is a empty indices attribute being created side by side.
What meaning about it?

Thanks!

should not be detail specific are you not getting it for point, prim, vertex attribute?

every custom attribute should give you separate :indices array, which is populated by indices if you import attribute as indexed primvar otherwise is empty, but it's important it is there in case you are layering nonindexed primvar over indexed one, as then it needs to zero out the indices array

I used detail attribute. As my understanding, it is a single value, so Sop Import shouldn't create indices attribute. Maybe a bug?

What @tamte says is correct, and it is true regardless of the type/interpolation of the primvar being authored, because we have no way to know what type/interpolation of primvar may be getting overwritten by this SOP-generated layer.