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Alembic export & import support in Blender.

Join the discussion about Blender's Alembic support at T51195

More background information is collected on the wiki.

Recent Activity

Yesterday

Sybren A. Stüvel (sybren) added a comment to T51351: Export procedual mesh animation with alembic.

@Karlis Stigis (karlisstigis) Thanks for the example. I suspect you're looking at the effects of T65816: Exporting procedural mesh animation with Alembic results in a static mesh which is waiting for T60094: Render crash when using Python API to modify object data in frame_change_pre handler to be fixed first.

Wed, Aug 21, 11:18 AM · Alembic, BF Blender
Karlis Stigis (karlisstigis) added a comment to T51351: Export procedual mesh animation with alembic.

@Sybren A. Stüvel (sybren) Here is a simple example file where multiple meshes get combined in one. Of course in cases where geometry is generated completely from scratch, exporting to Alembic makes more sense, but combining many objects in one is still useful, because then you can reimport those as 1 alembic file and not mess around with hundreds of objects + retime animation.

Wed, Aug 21, 3:30 AM · Alembic, BF Blender

Tue, Aug 20

Martin Felke (scorpion81) added a comment to D5535: Cache File frame scale option.

Ok, seems the desired effect of variable speed control can be already achieved by animating the override frame and / or the frame offset. Furthermore it would have introduced hassles with the previous frame state being potentially inconsistent. Closing.

Tue, Aug 20, 6:57 PM · Alembic, BF Blender
Brecht Van Lommel (brecht) added a comment to D5535: Cache File frame scale option.

Modifier evaluation should be stateless (except for physics sims with caching). Behavior can't change depending on what the previous frame was, that breaks scrubbing and render farms. I don't think integrating animation curves is going to be practical either.

Tue, Aug 20, 6:41 PM · Alembic, BF Blender
Sybren A. Stüvel (sybren) added a comment to T49234: Alembic Import issues.

@Kévin Dietrich (kevindietrich) I suspected as much. Thanks for confirming ;-)

Tue, Aug 20, 5:58 PM · Alembic, Cycles, Import/Export, BF Blender
Sybren A. Stüvel (sybren) added a comment to D5535: Cache File frame scale option.

I don't think that a simple "don't move back" rule is going to be very useful. The problem is that when the frame_scale lowers, the Alembic timekey is computed in a way that assumes that frame_scale has always been that low. To get this working properly, I think you'll have to integrate the curve.

Tue, Aug 20, 5:46 PM · Alembic, BF Blender
Martin Felke (scorpion81) added a comment to D5535: Cache File frame scale option.
  • changed the RNA wording
  • exposed a readonly timecode to the UI
  • attempted to get rid of backward moving of objects when reducing the frame scale interactively or via keyframe, but objects seem to be temporarily stuck, any ideas for this ? Probably not properly solveable... hmm
Tue, Aug 20, 4:29 PM · Alembic, BF Blender
Sybren A. Stüvel (sybren) added inline comments to D5535: Cache File frame scale option.
Tue, Aug 20, 1:00 PM · Alembic, BF Blender
Kévin Dietrich (kevindietrich) added a comment to T49234: Alembic Import issues.

@Sybren A. Stüvel (sybren), sorry for the late response but I am not actively working on anything Blender related at the moment.

Tue, Aug 20, 12:16 PM · Alembic, Cycles, Import/Export, BF Blender
Sybren A. Stüvel (sybren) added a comment to D5535: Cache File frame scale option.

LGTM. Can you also add a unit test that uses both the frame scale and offset?

Tue, Aug 20, 11:32 AM · Alembic, BF Blender
Martin Felke (scorpion81) added a reviewer for D5535: Cache File frame scale option: Sybren A. Stüvel (sybren).
Tue, Aug 20, 11:16 AM · Alembic, BF Blender
Martin Felke (scorpion81) created D5535: Cache File frame scale option.
Tue, Aug 20, 11:09 AM · Alembic, BF Blender

Mon, Aug 19

Sybren A. Stüvel (sybren) added a comment to T50725: Alembic export doesn't take 'Custom Properties', as alembic non-standard data..

@Philip Luk (PixelTrader) that's good news! If you want you can upload it as a diff to Differential; that way I can take a look at the approach you're taking and give some feedback before you spend too much time polishing things ;-)

Mon, Aug 19, 2:31 PM · Alembic, Import/Export, BF Blender
Sybren A. Stüvel (sybren) added a comment to T51351: Export procedual mesh animation with alembic.

@Karlis Stigis (karlisstigis) Please make it possible for us to verify this, by providing us with an example blend file and clear steps on how to reproduce. Also, 'b2.8' is not really a clear indication of which exact version of Blender you tested with; please test with the latest daily build from https://builder.blender.org/download/.

Mon, Aug 19, 2:29 PM · Alembic, BF Blender
Philip Luk (PixelTrader) added a comment to T50725: Alembic export doesn't take 'Custom Properties', as alembic non-standard data..

Hello All,

Mon, Aug 19, 1:06 AM · Alembic, Import/Export, BF Blender

Sat, Aug 17

Karlis Stigis (karlisstigis) added a comment to T51351: Export procedual mesh animation with alembic.

It seems this is still a problem in b2.8

Sat, Aug 17, 1:50 AM · Alembic, BF Blender

Fri, Aug 16

Sybren A. Stüvel (sybren) added a comment to T50725: Alembic export doesn't take 'Custom Properties', as alembic non-standard data..

@Christophe Leyder (shotalot) It's not a trivial thing to solve. It'll take more time, can't make any promises as to when there is enough time to implement it. It's still on the TODO list, though.

Fri, Aug 16, 6:58 PM · Alembic, Import/Export, BF Blender
Sybren A. Stüvel (sybren) added a comment to T63654: Alembic - Aplly scale doesn't work with the Mesh Sequence and hair.

Since last asking for information it has been 7 or more days, due to the policy of our bug tracker we will have to archive the report until the requested information is given.

Fri, Aug 16, 2:56 PM · Alembic, BF Blender
Sybren A. Stüvel (sybren) closed T56408: Hair interpolated children recalculation on every frame when attached onto an alembic imported mesh as Resolved by committing rBee8aad79c159: Fix T56408: Hair children recalc on every frame on Alembic mesh.
Fri, Aug 16, 2:54 PM · Alembic, BF Blender
Sybren A. Stüvel (sybren) added a comment to T55288: Alembic export do scale when rotating more than 360`.

I've done some digging, and it seems to be an issue with the reading applications. Both Gaffer and USDView show the wobbling scale issue. Exporting @colin (col-one)'s file with 24 FPS and then importing into Gaffer or USDView works fine. It's when there is a different frame rate that these programs fail.

Fri, Aug 16, 2:02 PM · Alembic, BF Blender
Philipp Oeser (lichtwerk) added a project to T54734: Alembic Import does not respect remap relative: Alembic.
Fri, Aug 16, 11:11 AM · Alembic, BF Blender

Tue, Aug 13

Brecht Van Lommel (brecht) added a comment to T56408: Hair interpolated children recalculation on every frame when attached onto an alembic imported mesh.

With mdd cache there is an original mesh with fixed coordinates that are being deformed, with Alembic there are only the deformed coordinates.

Tue, Aug 13, 6:40 PM · Alembic, BF Blender
Yegor (Yegor) added a comment to T56408: Hair interpolated children recalculation on every frame when attached onto an alembic imported mesh.

It's not just a change in tessellation, changing vertex position and face areas can lead to a different child particle distribution even if the tessellation is the same.

Tue, Aug 13, 5:56 PM · Alembic, BF Blender
Sybren A. Stüvel (sybren) added a comment to T54050: Camera focal length animation not importing.

I don't think we can use the same approach as @Bastien Montagne (mont29) did in b890f0d7e8a6 for Alembic. The FBX addon loads the entire animation into a Blender F-Curve at import time. This contrasts the streaming approach we use when reading Alembic, where modifiers and constraints are used to read the Alembic file at a certain timecode and apply that to Blender. @Kévin Dietrich (kevindietrich) 's approach in D2324 looks good, but is almost 3 years old already.

Tue, Aug 13, 5:54 PM · Add-ons, Alembic, Import/Export, BF Blender
Brecht Van Lommel (brecht) added a comment to T56408: Hair interpolated children recalculation on every frame when attached onto an alembic imported mesh.

It's not just a change in tessellation, changing vertex position and face areas can lead to a different child particle distribution even if the tessellation is the same.

Tue, Aug 13, 4:06 PM · Alembic, BF Blender
Sybren A. Stüvel (sybren) lowered the priority of T56408: Hair interpolated children recalculation on every frame when attached onto an alembic imported mesh from Waiting for Developer to Reproduce to Confirmed, Medium.
Tue, Aug 13, 4:06 PM · Alembic, BF Blender
Sybren A. Stüvel (sybren) added a comment to T56408: Hair interpolated children recalculation on every frame when attached onto an alembic imported mesh.

I discussed this with Brecht, and it's probably due to the way hair is distributed over the mesh. This is done using the tesselated faces (which are tris or quads), which in turn are based on the original mesh coordinates. Blender loads deforming meshes from Alembic into its own memory, so the current frame is always seen as "the original". This means a potential change in tesselation, which means a potential change in hair positions.

Tue, Aug 13, 3:59 PM · Alembic, BF Blender
Sybren A. Stüvel (sybren) merged T63534: Child hair particles set to "Interpolated" causes jittering when groom on alembic cache into T56408: Hair interpolated children recalculation on every frame when attached onto an alembic imported mesh.
Tue, Aug 13, 3:46 PM · Alembic, BF Blender
Sybren A. Stüvel (sybren) merged task T63534: Child hair particles set to "Interpolated" causes jittering when groom on alembic cache into T56408: Hair interpolated children recalculation on every frame when attached onto an alembic imported mesh.
Tue, Aug 13, 3:45 PM · Alembic, BF Blender
Sybren A. Stüvel (sybren) added a project to T56408: Hair interpolated children recalculation on every frame when attached onto an alembic imported mesh: Alembic.
Tue, Aug 13, 3:45 PM · Alembic, BF Blender
Sybren A. Stüvel (sybren) added a comment to T63654: Alembic - Aplly scale doesn't work with the Mesh Sequence and hair.

This is probably the same issue as T63534.

Tue, Aug 13, 3:44 PM · Alembic, BF Blender

Fri, Aug 9

Philipp Oeser (lichtwerk) raised the priority of T63534: Child hair particles set to "Interpolated" causes jittering when groom on alembic cache from Needs Information from User to Waiting for Developer to Reproduce.
Fri, Aug 9, 12:46 PM · Alembic, BF Blender
Philipp Oeser (lichtwerk) added a comment to T63534: Child hair particles set to "Interpolated" causes jittering when groom on alembic cache.

@Sybren A. Stüvel (sybren): I have updated T56408 with a file that has both abc and pc2 caches (pc2 renders fine, abc not) including the output sequences.

Fri, Aug 9, 12:46 PM · Alembic, BF Blender
Sybren A. Stüvel (sybren) added a comment to T63534: Child hair particles set to "Interpolated" causes jittering when groom on alembic cache.

@Libor Batek (lbatek) please provide us with a valid example file. The ABC file from the attached zip seems to be corrupt:

Fri, Aug 9, 11:08 AM · Alembic, BF Blender
Philipp Oeser (lichtwerk) added a comment to T49234: Alembic Import issues.

I would also be interested in D2324 to get some love, @Sybren A. Stüvel (sybren): have you checked that?

Fri, Aug 9, 11:03 AM · Alembic, Cycles, Import/Export, BF Blender
Sybren A. Stüvel (sybren) added a comment to T49234: Alembic Import issues.

@Kévin Dietrich (kevindietrich) Are you still working on this?

Fri, Aug 9, 10:53 AM · Alembic, Cycles, Import/Export, BF Blender

Fri, Aug 2

Sybren A. Stüvel (sybren) added a comment to T60977: Alembic vertex color export does not work in maya.

Thanks for testing. This seems to be a Maya issue, and not a Blender issue, so I'll close this task.

Fri, Aug 2, 9:38 AM · Alembic, BF Blender

Thu, Aug 1

Steffen Dünner (SteffenD) added a comment to T60977: Alembic vertex color export does not work in maya.

vertexColor_blender_colorSet1.abc is also working fine in Houdini 17.5:

Thu, Aug 1, 5:14 PM · Alembic, BF Blender
Irfan Celik (irfan) added a comment to T60977: Alembic vertex color export does not work in maya.

I remember that I tried that as well. Anyway, it still does not show up in Maya 2017 and 2018. Funny enough, I tried it in 3ds max 2019 and there they are.

Thu, Aug 1, 5:08 PM · Alembic, BF Blender
Sybren A. Stüvel (sybren) added a comment to T63654: Alembic - Aplly scale doesn't work with the Mesh Sequence and hair.

Blender's hair system is very picky when it comes to the mesh it's attached to. Especially when grooming, it is vital that the face & vertex indices remain the same. Are you sure that the mesh in Alembic didn't change between grooming the hair in Blender and getting these errors?

Thu, Aug 1, 4:42 PM · Alembic, BF Blender
Sybren A. Stüvel (sybren) lowered the priority of T60977: Alembic vertex color export does not work in maya from Normal to Needs Information from User.
Thu, Aug 1, 4:10 PM · Alembic, BF Blender
Sybren A. Stüvel (sybren) added a comment to T60977: Alembic vertex color export does not work in maya.

The structure in Alembic seems to be the same in both files. Both use a subproperty of .arbGeomParams, and both use indexed colours (thanks to D3704). Maybe Maya is very particular about the name of the vertex colour map? That's the only real difference I see; the Blender-produced file has Col whereas the Maya-produced file has colorSet1.

Thu, Aug 1, 4:10 PM · Alembic, BF Blender

Tue, Jul 30

Sybren A. Stüvel (sybren) added a comment to T56792: Alembic doesn't export custom normals correctly.

Thanks for confirming :)

Tue, Jul 30, 6:31 PM · Import/Export, Alembic, BF Blender
Steffen Dünner (SteffenD) added a comment to T56792: Alembic doesn't export custom normals correctly.

@Sybren A. Stüvel (sybren) : I just gave the very latest master ( 7f29fc7415a4 ) a quick try and now the normals are perfect for both Alembic im- and export. Much appreciated! Thanks!

Tue, Jul 30, 5:21 PM · Import/Export, Alembic, BF Blender
Sybren A. Stüvel (sybren) closed D5191: Alembic: import & export face-varying normals.
Tue, Jul 30, 5:07 PM · Alembic, BF Blender
Sybren A. Stüvel (sybren) closed T65717: Alembic (camera - also mesh) import scale issue as Resolved by committing rB0dece50667f1: Fix T65717: Alembic (camera - also mesh) import scale issue.
Tue, Jul 30, 4:56 PM · Alembic, BF Blender

Tue, Jul 23

Bastien Montagne (mont29) added a comment to T66640: alembic files bug.

More than a week without reply or activity. Due to the policy of the tracker archiving for until required info/data are provided.

Tue, Jul 23, 3:17 PM · Alembic, BF Blender

Jul 18 2019

martin Naydenski (martinium) added a comment to T56792: Alembic doesn't export custom normals correctly.

Thanks, Sybren! Do you have an idea when we can expect 2.81 to be open so we can test it?

Jul 18 2019, 8:09 PM · Import/Export, Alembic, BF Blender
Sybren A. Stüvel (sybren) added a comment to T65717: Alembic (camera - also mesh) import scale issue.

@Philipp Oeser (lichtwerk) I can't see that BLI_assert failure here, maybe it's been fixed already.

Jul 18 2019, 3:45 PM · Alembic, BF Blender
Sybren A. Stüvel (sybren) added a comment to T65717: Alembic (camera - also mesh) import scale issue.

Fixed in D5290, will likely be part of 2.81.

Jul 18 2019, 3:42 PM · Alembic, BF Blender