Alembic not importing motion blur #49234

Closed
opened 2016-09-02 22:49:11 +02:00 by Rod Tebisx · 35 comments

System Information
Linux Mint

Blender Version
Broken: 2.77 7dc328e
Worked: (optional)

Short description of error

Imported animated alembic mesh not render motion blur with Cycles, even with correct "motion blur / Deformation flag" on and steps set to 12 (for example)

Exact steps for others to reproduce the error
Just Import alembic mesh to see not working motion blur with animated mesh

**System Information** Linux Mint **Blender Version** Broken: 2.77 7dc328e Worked: (optional) **Short description of error** Imported animated alembic mesh not render motion blur with Cycles, even with correct "motion blur / Deformation flag" on and steps set to 12 (for example) **Exact steps for others to reproduce the error** Just Import alembic mesh to see not working motion blur with animated mesh
Author

Changed status to: 'Open'

Changed status to: 'Open'
Author

Added subscriber: @RodTebisx

Added subscriber: @RodTebisx

Added subscribers: @kevindietrich, @EjnerFergo

Added subscribers: @kevindietrich, @EjnerFergo

Imported camera focal length is not supported yet, but @kevindietrich is working on it. See this post:
https://blenderartists.org/forum/showthread.php?399763-Alembic-I-O&p=3086622&viewfull=1#post3086622

Imported camera focal length is not supported yet, but @kevindietrich is working on it. See this post: https://blenderartists.org/forum/showthread.php?399763-Alembic-I-O&p=3086622&viewfull=1#post3086622
Kévin Dietrich was assigned by Bastien Montagne 2016-09-04 09:49:53 +02:00
Author

Thanks guys for reviewing this! :)

Thanks guys for reviewing this! :)

@RodTebisx for the motion blur case, are you referring to meshes with varying number of vertices (like fluids) or any kind of meshes? For the first case this is a known to-do with a patch in the works (D2388).

@RodTebisx for the motion blur case, are you referring to meshes with varying number of vertices (like fluids) or any kind of meshes? For the first case this is a known to-do with a patch in the works ([D2388](https://archive.blender.org/developer/D2388)).
Author

For the case teste, the vertex number is constant, so is it possible to calculate proper motion blur.
Anyway, as an additional step, please check if possible to import "v" vector attribute on points (v is velocity vector attribute coming from Houdini alembic) and use as motion vector to make Cycles 2.5D motion blur.

For the case teste, the vertex number is constant, so is it possible to calculate proper motion blur. Anyway, as an additional step, please check if possible to import "v" vector attribute on points (v is velocity vector attribute coming from Houdini alembic) and use as motion vector to make Cycles 2.5D motion blur.

Added subscriber: @knekke

Added subscriber: @knekke

+1 on the motionblur! Also an option to scale the velocity would be nice, and maybe an option to choose the channelname that provides the velocity as it might be different depending on the app that creates the alembic. Thanks!

+1 on the motionblur! Also an option to scale the velocity would be nice, and maybe an option to choose the channelname that provides the velocity as it might be different depending on the app that creates the alembic. Thanks!

Added subscriber: @SteffenD

Added subscriber: @SteffenD
Member

Added subscriber: @lichtwerk

Added subscriber: @lichtwerk
Member

Added subscriber: @dr.sybren

Added subscriber: @dr.sybren
Member

Just wanted to check the status on the import-of-animated-camera-focal-length issue:

  • this seems to be a design issue? [no modifier/constraint available to update a specific FCurve....]
  • some digging brings up https:*github.com/diekev/blender/tree/abc_fcurve (example https:*www.youtube.com/watch?v=ypZIpJ2USpU)
  • @kevindietrich : are you still working on this?
  • @dr.sybren : do you see a chance of this comming to master?
Just wanted to check the status on the `import-of-animated-camera-focal-length` issue: - this seems to be a design issue? [no modifier/constraint available to update a specific FCurve....] - some digging brings up https:*github.com/diekev/blender/tree/abc_fcurve (example https:*www.youtube.com/watch?v=ypZIpJ2USpU) - @kevindietrich : are you still working on this? - @dr.sybren : do you see a chance of this comming to master?

@lichtwerk it looks interesting, but too big a feature to put into master for 2.80.

@lichtwerk it looks interesting, but too big a feature to put into master for 2.80.
Member

@dr.sybren: yep, not for 2.80, but this is the way to go, right? [having a cache-fcurve-modifier]
Or is there another possibility [from the design point of view]?

@dr.sybren: yep, not for 2.80, but this is the way to go, right? [having a cache-fcurve-modifier] Or is there another possibility [from the design point of view]?

I think the approach is pretty nice, as it'll give us a way forward to animate other properties as well.

I think the approach is pretty nice, as it'll give us a way forward to animate other properties as well.

I am not working on this anymore, although I could resume work. This approach was suggested to me by Campbell as a general way to import custom keyframes from alembic archives. The patch was uploaded for review a few years ago: D2324.

As for the motion blur patch (D2388), it needs some custom parameters to scale the "velocity" vectors with, as most software export the acceleration (dV / dt) and not the velocity (dP / dt).

I am not working on this anymore, although I could resume work. This approach was suggested to me by Campbell as a general way to import custom keyframes from alembic archives. The patch was uploaded for review a few years ago: [D2324](https://archive.blender.org/developer/D2324). As for the motion blur patch ([D2388](https://archive.blender.org/developer/D2388)), it needs some custom parameters to scale the "velocity" vectors with, as most software export the acceleration (dV / dt) and not the velocity (dP / dt).
Member

@kevindietrich : thx for getting back! will read those...
Also note that #54050 is the same thing...

@kevindietrich : thx for getting back! will read those... Also note that #54050 is the same thing...

Also I am having problems with sequences again: https://developer.blender.org/T51820

Also I am having problems with sequences again: https://developer.blender.org/T51820

Added subscriber: @YegorSmirnov

Added subscriber: @YegorSmirnov

@kevindietrich Glad you came back! Could you please update your patch D2388 for the current code, so we could review and make it to the master finally, cause it's very important for fluid rendering.
If there's something I can assist with, let me know. I'm not a coder anymore, but maybe a can help.

@kevindietrich Glad you came back! Could you please update your patch [D2388](https://archive.blender.org/developer/D2388) for the current code, so we could review and make it to the master finally, cause it's very important for fluid rendering. If there's something I can assist with, let me know. I'm not a coder anymore, but maybe a can help.

@kevindietrich Are you still working on this?

@kevindietrich Are you still working on this?
Member

I would also be interested in D2324 to get some love, @dr.sybren: have you checked that?

I would also be interested in [D2324](https://archive.blender.org/developer/D2324) to get some love, @dr.sybren: have you checked that?

@dr.sybren, sorry for the late response but I am not actively working on anything Blender related at the moment.

@dr.sybren, sorry for the late response but I am not actively working on anything Blender related at the moment.

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

@kevindietrich I suspected as much. Thanks for confirming ;-)
Sybren A. Stüvel changed title from Alembic Import issues to Alembic not importing camera focal length or motion blur 2019-08-22 16:59:27 +02:00

Changing the classification from 'Bug' to 'To Do', as this is a known limitation.

Changing the classification from 'Bug' to 'To Do', as this is a known limitation.
Sybren A. Stüvel changed title from Alembic not importing camera focal length or motion blur to Alembic not importing motion blur 2019-08-22 17:58:12 +02:00

I have removed the camera focal length from the task description, as that is already covered by #54050.
Now this task has only a single topic: importing data required for computing motion blur (probably vertex velocities is enough).

I have removed the camera focal length from the task description, as that is already covered by #54050. Now this task has only a single topic: importing data required for computing motion blur (probably vertex velocities is enough).

Added subscriber: @MichaelHermann

Added subscriber: @MichaelHermann

For those who haven't noticed, I updated and fixed the patch D2388, please try it if you can!

For those who haven't noticed, I updated and fixed the patch [D2388](https://archive.blender.org/developer/D2388), please try it if you can!

I have some blurriness, but it doesn't seem to look right. (see Images)
This is a particle system that I exported and then reimported to reverse the movement. And the plane is a dupliobject on the vertices of the ABC.
I would not expect to see a clear outline of the plane in the image with motion blur. Also, the position of the blur is set to Center. But this seems more like Start. And the shutter duration also has no effect.

alembic_blur.png

alembic_noblur.png

I also attached a simplified blendfile (+ cache) which has the same issues.
Let me know if I did sth. wrong.

I updated to the latest daily build half an hour ago before testing.alembic_mbur.blend

mblur_test.abc

I have some blurriness, but it doesn't seem to look right. (see Images) This is a particle system that I exported and then reimported to reverse the movement. And the plane is a dupliobject on the vertices of the ABC. I would not expect to see a clear outline of the plane in the image with motion blur. Also, the position of the blur is set to Center. But this seems more like Start. And the shutter duration also has no effect. ![alembic_blur.png](https://archive.blender.org/developer/F7794816/alembic_blur.png) ![alembic_noblur.png](https://archive.blender.org/developer/F7794818/alembic_noblur.png) I also attached a simplified blendfile (+ cache) which has the same issues. Let me know if I did sth. wrong. I updated to the latest daily build half an hour ago before testing.[alembic_mbur.blend](https://archive.blender.org/developer/F7794843/alembic_mbur.blend) [mblur_test.abc](https://archive.blender.org/developer/F7794844/mblur_test.abc)

You have to apply the patch and compile Blender to test the feature, it is not in the daily builds. Also your file does not have velocity information (the array size is 0). So without the patch and without custom velocities, Cycles is just using an interpolation between the previous, current, and next frames.

You have to apply the patch and compile Blender to test the feature, it is not in the daily builds. Also your file does not have velocity information (the array size is 0). So without the patch and without custom velocities, Cycles is just using an interpolation between the previous, current, and next frames.

In #49234#791232, @kevindietrich wrote:
You have to apply the patch and compile Blender to test the feature, it is not in the daily builds. Also your file does not have velocity information (the array size is 0). So without the patch and without custom velocities, Cycles is just using an interpolation between the previous, current, and next frames.

Ah ok. Sorry then. I applied the patch but can't get Blender to build right now, or it crashes on startup. If I manage to build it, I'll test again. Thank you!

> In #49234#791232, @kevindietrich wrote: > You have to apply the patch and compile Blender to test the feature, it is not in the daily builds. Also your file does not have velocity information (the array size is 0). So without the patch and without custom velocities, Cycles is just using an interpolation between the previous, current, and next frames. Ah ok. Sorry then. I applied the patch but can't get Blender to build right now, or it crashes on startup. If I manage to build it, I'll test again. Thank you!

I managed to run a few tests and it works!

I managed to run a few tests and it works!

Changed status from 'Confirmed' to: 'Resolved'

Changed status from 'Confirmed' to: 'Resolved'

Committed motion blur support patch b5dcf74636, so this can be closed.

Committed motion blur support patch b5dcf74636, so this can be closed.
Thomas Dinges added this to the 2.91 milestone 2023-02-08 16:21:50 +01:00
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Reference: blender/blender#49234
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