Maniphest T63534

Child hair particles set to "Interpolated" causes jittering when groom on alembic cache
Closed, Duplicate
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Assigned To
Sybren A. Stüvel (sybren)
Authored By
Libor Batek (lbatek)
Apr 12 2019, 3:05 PM
Tags
  • BF Blender
  • Alembic
Subscribers
Brecht Van Lommel (brecht)
carlos puebla (negativecitizen)
Evan Ryan (evantryan)
Libor Batek (lbatek)
Philipp Oeser (lichtwerk)
Serj Maiorov (printerkiller)
Sybren A. Stüvel (sybren)

Description

Blender 2.8x
Win10

Hi,
THE PROBLEM is that if you turn on "CHILD PARTICLES" and SET them TO "INTERPOLATED" MODE it causes JITTERING of them
acros surface of the geo from which roots.

When selecting "Simple" mode everything works fine - No jitter at all, perfectly sticked to the geo.

You can test it simply by switching from mode to mode to see this problem. Its already setuped for rendering using eevee but same problem using
Cycles renderer.

Note that I ve briefly tried to change export settings for Alembic during export of anim but nothing helped...still causes this problem.

Also note that when outputting alembic cache for animated object using transforms not armatures, it works ok. But when exporting alembic from armature animated
object this causes this problem.

please see this Zip archive with readme info and example scene....

Hair_Test.zip191 KBDownload

Thank you,

Libor

Related Objects

Event Timeline

Libor Batek (lbatek) created this task.Apr 12 2019, 3:05 PM
Libor Batek (lbatek) added a comment.Apr 12 2019, 3:14 PM

here is some rendered animation with close up of the hair particles jittering on my animated model (alembic cache)

pls when viewing change quality below video to highest resolution (1080p) or just download and playback at your desktop

Thx again.
L.

Philipp Oeser (lichtwerk) updated the task description.Apr 12 2019, 3:28 PM
Philipp Oeser (lichtwerk) added a project: Alembic.
Philipp Oeser (lichtwerk) assigned this task to Sybren A. Stüvel (sybren).Apr 12 2019, 3:36 PM
Philipp Oeser (lichtwerk) lowered the priority of this task from 90 to 50.
Philipp Oeser (lichtwerk) added subscribers: Sybren A. Stüvel (sybren), Philipp Oeser (lichtwerk).

Confirmed on first sight
(Looks like 2.79 has a similiar issue even)

@Sybren A. Stüvel (sybren): mind having a look?

Sybren A. Stüvel (sybren) added a comment.Apr 15 2019, 10:25 AM

@Libor Batek (lbatek) please put the description of the issue in this task, instead of hiding it in a ZIP file. Hiding it like this makes it invisible to the search engine, and makes it harder for developers to access as well.

Libor Batek (lbatek) updated the task description.Apr 15 2019, 10:49 AM

@Sybren A. Stüvel (sybren) ok, sorry not doing it before....should be done right now

Serj Maiorov (printerkiller) added a subscriber: Serj Maiorov (printerkiller).Apr 18 2019, 12:56 PM

Have the same problem, here is a side by side basic test

Libor Batek (lbatek) added a comment.EditedApr 26 2019, 9:29 AM

I ve tested to render animation with mblur and hair on alembic cache and there is some problems too....not sure if it corelates to the above mentioned problems or its kind of new problem.

EXAMPLE_MOV (Apple ProRes)

still frame from animation with mblur...seems like hair particles doesnt refer to preceding frame position of the hair particles (not sure If I shouldnt use bake cache for particles??)

they spread from world origin

Evan Ryan (evantryan) added a subscriber: Evan Ryan (evantryan).Jun 23 2019, 7:58 PM
Philipp Oeser (lichtwerk) mentioned this in T66642: The rendering result of hair is diffirent in the diffirent version!!!.Jul 10 2019, 7:22 PM
Philipp Oeser (lichtwerk) added a comment.Jul 11 2019, 11:01 AM

T56408 might be related...

Philipp Oeser (lichtwerk) mentioned this in T67038: Alembic cache induces flickering and change of position on hair driven by that surfaces connected to it. .Jul 16 2019, 8:40 AM
Philipp Oeser (lichtwerk) merged a task: T67038: Alembic cache induces flickering and change of position on hair driven by that surfaces connected to it. .Jul 16 2019, 11:48 AM
Philipp Oeser (lichtwerk) added a subscriber: carlos puebla (negativecitizen).
Philipp Oeser (lichtwerk) added a subscriber: Brecht Van Lommel (brecht).Jul 16 2019, 11:52 AM

@Sybren A. Stüvel (sybren): any chance to have a look at this? [still wont consider this High prio -- but I know at least two other studios suffering from this as well, and having to go .mdd/.pc2 instead...]
(how did this work for Spring btw.?)

CC @Brecht Van Lommel (brecht)

Sybren A. Stüvel (sybren) lowered the priority of this task from 50 to 30.Aug 9 2019, 11:08 AM

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

% abctree testMesh_anim.abc -a
ABC
 :--.childBnds
 `--Armature
     | :--.xform
     | :    :--.inherits
     | :    :--.ops
     | :    `--.vals
     :--visible
     `--TestMesh
         | :--.xform
         | :    :--.inherits
         | :    :--.ops
         | :    `--.vals
         :--visible
         `--TestMeshShape
             | `--.geom
             |    :--.selfBnds
             |    :--P
             |    :--.faceIndices
             |    :--.faceCounts
             |    | :--.userProperties
             |    | :    `--meshtype
terminate called after throwing an instance of 'Alembic::Util::v10::Exception'
  what():  ICompoundProperty::getPropertyHeader()
ERROR: EXCEPTION:
Out of range index in CprData::getPropertyHeader: 18446744073709551615
zsh: abort (core dumped)  abctree testMesh_anim.abc -a
In T63534#723681, @Philipp Oeser (lichtwerk) wrote:

I know at least two other studios suffering from this as well, and having to go .mdd/.pc2 instead...

It would be helpful if they could provide:

  • An as-simple-as-possible ABC file that shows this issue,
  • An MDD or PC2 file of the same source that does not show this issue,
  • The blend file used to generate those files, and
  • A blend file that imports & shows the problems.

(how did this work for Spring btw.?)

AFAIK we didn't put hair on top of Alembic cashes.

Philipp Oeser (lichtwerk) mentioned this in T56408: Hair interpolated children recalculation on every frame when attached onto an alembic imported mesh.Aug 9 2019, 12:43 PM
Philipp Oeser (lichtwerk) added a comment.Aug 9 2019, 12:46 PM

@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.

I assume these reports are really about the same issue (and could be merged?)

Philipp Oeser (lichtwerk) raised the priority of this task from 30 to 80.Aug 9 2019, 12:46 PM
Sybren A. Stüvel (sybren) mentioned this in T63654: Alembic - Aplly scale doesn't work with the Mesh Sequence and hair.Aug 13 2019, 3:44 PM
Sybren A. Stüvel (sybren) closed this task as a duplicate of T56408: Hair interpolated children recalculation on every frame when attached onto an alembic imported mesh.
Sybren A. Stüvel (sybren) mentioned this in rBee8aad79c159: Fix T56408: Hair children recalc on every frame on Alembic mesh.Aug 16 2019, 2:54 PM