Is it possible to edit a cached animated alembic, like move points to fix issues

Hi,

I would like to know if it’s possible in Blender to overwrite at some frame the backed animated meshes to fix issue like geometries intersections using the sculpt tool, a hook modifier or a shape key. I need to clean / fix some mistake on cached alembic and maybe USD from animation department.

Thank you

Matt

You don’t typically “fix” cached stuff, because the point of a cache is to store the results of calculations and use that stored data for future reference. In Blender animations case, it’ll store the animation data, and Blender will read from that cache instead of calculating it fresh each time. This has the benefit of significantly increasing performance.

To correct problems, you’re normally better off deleting the cache (make sure you’re at frame 1 so any animations or simulations are at the starting position), correcting the problem, and then recreating (or rebaking) the cache.

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Oki, so not possible in Blender to fix a cached alembic like in Maya with a cluster or like with Chronosculpt. It essential to be able to fix upper a point cache in production if you’re not the animation studio and you received only caches and after the animation departement or the vfx one is closed need to fix some little issue like cloth problem that go trought a part of the characters or something like that.

I will ask to have access to Maya for some days to fix the issue I have. Thank you for your answer. I hope geometry node or a Chronosculpt like tool will be able in Blender for cached data.

Thanks,

Matt

For some mesh there is the possibilty to make vertex groups and use a hook modifier bound to an empty for example to pull some of the vertices “elsewhere” … never tried this on a animated mesh…

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Hi,

Oki, I will try it, thank you

Matt

When you import an alembic file or USD, objects are created with a constraint or a modifier or both.
That depends on what is animated in file and import options.

A Mesh Sequence Cache modifier will overwrite base mesh. So, an attempt to sculpt it or use shapekeys will fail.
But such animation can be re-exported as a MDD file and re-imported, when importing an MDD file, you obtain a mesh animated by shapekeys. At that moment, you can sculpt corrective shapekeys.

A Transform Cache constraint will overwrite transform properties animation of object. So, an attempt to create an offset by tweaking object location will fail.
But you can parent object to an empty and move empty.

You can animate enabling/disabling of these modifier and constraint.
You can add almost any modifier and constraint after them, in modifier’s stack and constraint’s stack.
You can use geometry nodes.
You can tweak timing of modifier and constraint.

Hi all,

Thank for your answers. I tried to make a vertex group and a hook (close to Maya cluster) and it’s working great and I keep the animation. I will try to use geometry nodes to see if I can gain more control but this solved my problem. I will try MDD file process too.

Thanks again for all your answers.

Matt