Attribute in Alembic with multi ID txt

[david.anastacio]

Hi,

Not sure if this is a bug or just the way it is.
When fetching an attribute with an user integer into a multiId texture, I'm getting some artifacts if I don't unpack the geo. This is not the case if I fetch the same attribute with a user float and avoid the conversion on the fly from integer to float. The attribute I'm fetching is an integer and it is baked into the alembic.

Unpacked geo using user integer:



Packed geo using user integer, some interpolation artifacts can be seen along the triangles of all objects:



Packed geo using a user float:



Best,
David.

[Gosho.Genchev]

Yes, the multi-id texture expects a float input texture - the attribute can still be an int. It will try to blend if the ID value is not a round number. I caught me off-guard a while ago, too but it's not a bug per-se.

Hope that helps!

[david.anastacio]

Gosho.Genchev, also thought this was just a feature and not a bug, just wanted to confirm. Avoid integer to float conversion on the fly.

But btw, all my values are integers so no blending/rounding is needed, so why does it still try to blend when you have packed geo?

Best,
David.

[Gosho.Genchev]

To be fair, I can't give you an in-depth developer-style answer - attributes are handled differently between regular geometry and alembics stored on disk. If you unpack the alembic, it's just like any other geo.
I'll check with the devs if there's the possibility to handle this so it produces the same result as User Float - it's User Int that seems to be doing something unusual here when passed as float input.

[david.anastacio]

All good, it works, for sure they are busy with other stuff that is more important. Was more curiosity in this case.
If they have an opening in their time might be usefull to fix it so other user don't have to go through this.

Thanks