Broken FCurve rendering #110169

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opened 2023-07-16 14:06:35 +02:00 by sanek122005 · 8 comments

sanek122005 commented

2023-07-16 14:06:35 +02:00

System Information
System: Ubuntu 20.04
VideoCard: Geforce MX230

Blender Version
Broken: 3.5, 3.6, 4.0

Short description of error
In one of my animation files, I can observe a broken display of animation curves:

when the Normalize option is enabled, one of the curves moves across the screen
the curves have extremely low resolution

This error is present in the curves of only one bone - hand_IK_control.R. For the rest of the bones, the curves display works as expected

The error does not disappear when you restart the blender, PC, reset settings

Exact steps for others to reproduce the error

Open file
Select hand_IK_control.R
See graph Editor
Select any other bone
See graph editor

**System Information** System: Ubuntu 20.04 VideoCard: Geforce MX230 **Blender Version** Broken: 3.5, 3.6, 4.0 **Short description of error** In one of my animation files, I can observe a broken display of animation curves: 1) when the Normalize option is enabled, one of the curves moves across the screen 2) the curves have extremely low resolution ![Screenshot_20230716_145338.png](/attachments/3c9bb0fd-f5ba-4a08-84b6-48cdc7c06c92) This error is present in the curves of only one bone - hand_IK_control.R. For the rest of the bones, the curves display works as expected ![Screenshot_20230716_145447.png](/attachments/e23d54c7-588a-4267-a741-c517fd565124) The error does not disappear when you restart the blender, PC, reset settings **Exact steps for others to reproduce the error** 1. Open file 2. Select hand_IK_control.R 3. See graph Editor 4. Select any other bone 5. See graph editor

Screenshot_20230716_145338.png

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Screenshot_20230716_145447.png

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walk_cycle_bug.blend

6.5 MiB

sanek122005 added the

labels 2023-07-16 14:06:36 +02:00

YimingWu commented

2023-07-17 04:54:45 +02:00

Member

Hi! It looks consistent to me. if you move other bone's key frame that close (1 frame interval in the case of hand_IK_control.R), they will show up segmented like that. It's already sub-frame scale, and blender is drawing 6 segments per frame on the f-curve, it's probably good enough as a representation.

Hi! It looks consistent to me. if you move other bone's key frame that close (1 frame interval in the case of `hand_IK_control.R`), they will show up segmented like that. It's already sub-frame scale, and blender is drawing 6 segments per frame on the f-curve, it's probably good enough as a representation. ![图片](/attachments/5b397600-8659-4722-b416-2f9a46ca523c)

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Nathan Vegdahl commented

2023-08-03 09:54:15 +02:00

Member

I believe the curve resolution issue (point 2 in the issue description above) will be addressed by #110301. In addition to improving performance, that PR also switches to computing curve resolution based on its on-screen size, so it should scale up better when zooming in. (There will still be limits, of course, but this particular case should be addressed well.)

I don't understand what issue point 1 is describing, however.

I believe the curve resolution issue (point 2 in the issue description above) will be addressed by #110301. In addition to improving performance, that PR also switches to computing curve resolution based on its on-screen size, so it should scale up better when zooming in. (There will still be limits, of course, but this particular case should be addressed well.) I don't understand what issue point 1 is describing, however.

sanek122005 commented

2023-08-03 09:59:48 +02:00

Author

I don't understand what issue point 1 is describing, however.

> I don't understand what issue point 1 is describing, however. <video src="/attachments/ca3fdbb5-4cf8-40a6-86d7-2f74ca73f346" title="2023-08-03 10-58-51.mp4" controls></video>

2023-08-03 10-58-51.mp4

3.0 MiB

Nathan Vegdahl commented

2023-08-03 10:04:45 +02:00

Member

Got it! Indeed, that appears to be a bug. Thank you for the report and the video!

Got it! Indeed, that appears to be a bug. Thank you for the report and the video!

Nathan Vegdahl commented

2023-08-03 10:21:47 +02:00

Member

Indeed, #110301 resolves point 2 (curve drawing resolution). Before/after:

However, it does not resolve point 1, which is a separate issue.

Indeed, #110301 resolves point 2 (curve drawing resolution). Before/after: ![curve_resolution_before_after.png](/attachments/033925a7-cb55-40bc-8f44-33c444000368) However, it does not resolve point 1, which is a separate issue.

curve_resolution_before_after.png

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Nathan Vegdahl added

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labels 2023-08-03 10:40:07 +02:00

Nathan Vegdahl self-assigned this 2023-08-03 10:56:45 +02:00

Nathan Vegdahl commented

2023-08-03 11:59:45 +02:00

Member

Point 1 appears to be a floating point precision issue. That particular curve is almost completely flat, but is off just enough for normalizing to try to expand it. However, due to how tiny the deviation from flatness is, the transform to expand it vertically ends up having precision issues.

I'll investigate a fix. The simplest fix would just be to bump up the size of the epsilon value used to determine when to expand a curve during normalization. But it's possible there may be a way to rearrange the floating point operations instead, so that they at least result in a consistent mapping.

Point 1 appears to be a floating point precision issue. That particular curve is *almost* completely flat, but is off just enough for normalizing to try to expand it. However, due to how tiny the deviation from flatness is, the transform to expand it vertically ends up having precision issues. I'll investigate a fix. The simplest fix would just be to bump up the size of the epsilon value used to determine when to expand a curve during normalization. But it's possible there may be a way to rearrange the floating point operations instead, so that they at least result in a consistent mapping.

Nathan Vegdahl referenced a pull request that will close this issue

2023-08-04 15:59:28 +02:00

Fix #110169: nearly flat normalized fcurves jump around in editor #110796

YimingWu commented

2023-08-06 06:49:11 +02:00

Member

@nathanvegdahl will #110301 generate some jitter when key frames are squeezed together visually and when you zoom, it will lose details especially around extreme positions?

@nathanvegdahl will #110301 generate some jitter when key frames are squeezed together visually and when you zoom, it will lose details especially around extreme positions?

Nathan Vegdahl referenced this issue from a commit

2023-08-07 10:53:10 +02:00

Fix #110169: nearly flat normalized fcurves jump around in editor

Nathan Vegdahl closed this issue

2023-08-07 10:53:11 +02:00

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labels 2023-08-07 10:53:12 +02:00

Nathan Vegdahl commented

2023-08-07 11:13:43 +02:00

Member

@ChengduLittleA

will #110301 generate some jitter when key frames are squeezed together visually and when you zoom, it will lose details especially around extreme positions?

I don't believe it will cause any noticeable visual issues. And the testing I've done of it so far seems to confirm that.

Also, I just landed a fix for point 1 in #110796. So I believe in combination with #110301, that closes out this issue. But @sanek122005 definitely let us know if any issues persist.

@ChengduLittleA > will #110301 generate some jitter when key frames are squeezed together visually and when you zoom, it will lose details especially around extreme positions? I don't believe it will cause any noticeable visual issues. And the testing I've done of it so far seems to confirm that. Also, I just landed a fix for point 1 in #110796. So I believe in combination with #110301, that closes out this issue. But @sanek122005 definitely let us know if any issues persist.

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