PF3 4D Noise animation eases in/out? No linear anim?

[terp]

Hello!

I want to have a simple animated cloud layer using a power fractal v3 as my density.
On the PF's animation tab, I check the box for 4d Noise.   The cloud seems to ease-in and ease-out of motion from beginning to end.
I would like the clouds to be animating linearly...always moving, no speed-up or slow-down.
I don't see any access to a curve, and from the forums I see animating the speed won't help this?

Is this the case?

I see easy clouds may have a lot more control.

Thanks!
T

[Kevin Kipper]

Hi terp,

Are you saying that when the Power fractal's 4d Noise is enabled but the 4d Noise speed parameter remains a single value, that the cloud seems to ease-in and out?  Or, is the 4d Noise checkbox enabled AND the 4d Noise speed parameter has also been animated?  

If it's the later, you can change the keyframe interpolation mode from TCB to Linear within the Animation panel.

If it's the former, perhaps you can set the keyframe to the same value on frame 1 and frame 100 (for example) and then set the interpolation mode to Linear.  That's just a quick guess, I've not tried it.

[terp]

EDIT: I believe this is user-error.  I was also translating the clouds as a whole with a transform input node, and one of the axes was still a non-linear curve.
I ran a test with the animation value key-framed to be a constant value (I set it to linear in the animation graph as well) which didn't change anything.

Yes, enabling 4D Noise ONLY, with a constant [non-animated] value looks like the motion eases-in and out.
We need constant motion for our use-case...no eases.

I've seen other users rotating fractals in Y linearly to get constant (looping as well) animation.
I'm sure there are other workarounds people have found...