fcurve modifier scaling oddity #43104

New Issue

lower case · 2015-01-03T01:51:36+01:00

lower case commented

2015-01-03 01:51:36 +01:00

System Information
Win7 64

Blender Version
Broken: 2.6, 2.7

Short description of error
something funny happens when adding a noise modifier to an fcurve and time scaling is set to certain values... not big deal and may be just a limitation but thought of filling as a bug anyway

Exact steps for others to reproduce the error
add a rotation keyframe to default cube, add a noise modifier to some fcurve, set modifier strength to 10 and scale to 0.1, press play and nothing happens... now set scale to 0.999 or .101 and it works fine! same happens with .025 or .05

noise.blend

**System Information** Win7 64 **Blender Version** Broken: 2.6, 2.7 **Short description of error** something funny happens when adding a noise modifier to an fcurve and time scaling is set to certain values... not big deal and may be just a limitation but thought of filling as a bug anyway **Exact steps for others to reproduce the error** add a rotation keyframe to default cube, add a noise modifier to some fcurve, set modifier strength to 10 and scale to 0.1, press play and nothing happens... now set scale to 0.999 or .101 and it works fine! same happens with .025 or .05 [noise.blend](https://archive.blender.org/developer/F134873/noise.blend)

lower case commented

2015-01-03 01:51:36 +01:00

Changed status to: 'Open'

lower case commented

2015-01-03 01:51:36 +01:00

Added subscriber: @lowercase

Aaron Carlisle commented

2015-01-03 01:55:10 +01:00

Added subscriber: @Blendify

Aaron Carlisle commented

2015-01-03 01:56:10 +01:00

Please try with blender from https://builder.blender.org/download/

lower case commented

2015-01-03 03:34:59 +01:00

get the blend and press play, all 3 planes should rotate... it does not work here

Joshua Leung self-assigned this 2015-01-03 05:44:39 +01:00

Joshua Leung commented

2015-01-03 05:44:39 +01:00

IIRC, a similar issue used to occur when using other combinations of settings. Assigning to self to have a quick check on this.

Campbell Barton commented

2015-03-15 23:08:23 +01:00

Added subscriber: @ideasman42

Campbell Barton commented

2015-03-15 23:08:23 +01:00

Its an interesting issue but easy to workaround by setting the phase.

setting as TODO.

Its an interesting issue but easy to workaround by setting the phase. setting as TODO.

Joshua Leung was unassigned by Sybren A. Stüvel

2020-11-09 18:34:04 +01:00

Sybren A. Stüvel commented

2021-01-21 16:53:50 +01:00

Added subscribers: @BassamKurdali, @dr.sybren

Sybren A. Stüvel commented

2021-01-21 16:53:50 +01:00

This still happens (@BassamKurdali tested), and having a scale=0.1 not work and scale=0.101 work does seem like a bug to me.

Falk David commented

2021-03-30 18:46:06 +02:00

Added subscriber: @filedescriptor

Falk David commented

2021-03-30 18:46:06 +02:00

Looked into this briefly. It seems to me that this is just a byproduct of how the Perlin Noise function (and its zero points) behaves. The function will be zero at integer intervals if the scale is a multiple of the phase and the offset is an integer. I guess a fix for this would be to set the offset to a default value of 0.5 (with a scale of 1.0, so half the scale). Then this would always give different values at integer (frame) intervals.

Sybren A. Stüvel commented

2021-06-04 12:19:59 +02:00

Changed status from 'Confirmed' to: 'Archived'

Sybren A. Stüvel closed this issue

2021-06-04 12:19:59 +02:00

Sybren A. Stüvel commented

2021-06-04 12:19:59 +02:00

Thanks for the analysis @filedescriptor . I take back my "this seems like a bug" and replace it with "this is by design".

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fcurve modifier scaling oddity #43104