"Euler Filter" in Houdini?

[Werner]

Does anyone know if Houdini has something similar to the 'Making Rotation Keys Continuous' command in Softimage?

In Maya it is called "Euler Filter "
Like this https://www.youtube.com/watch?v=zo0xhw1B2dE

 

From the Softimage Docs...for anyone not familiar with it.

"Making Rotation Keys Continuous

If you want to process more than one rotation fcurve at a time, you can choose the Make Rotation Keys Continuous command from the Animation panel. This command processes all rotation curves on an object together as a complete orientation instead of individual X, Y, and Z rotation function curves.

This command also processes the local and global rotation keyframes on the selected objects to minimize the change between successive Euler angle rotation keyframes, making the values continuous between keys. "

[yesyes]

you can do much more in houdini through chops.

Edited October 14, 2015 by yesyes

[amm]

Does anyone know if Houdini has something similar to the 'Making Rotation Keys Continuous' command in Softimage?

 

 

Nope. Now If you'll get idea to use quaternion interpolation instead, you'll find it only linear, no tension / continuity / bias or such. Which leads to conclusion, that Houdini animators are, actually, extra - terrestrials - I can't imagine another explanation. Anyway we will see in next few days, where Houdini is going, when it comes to animation.

[malexander]

In Houdini it's called Spherical Linear Interpolation (slerp), and is generally available in CHOPs, though I'm not sure if this is something available in the channel editor. Houdini, Maya and Softimage all use the same mathematical technique for rotation interpolation, which basically boils down to linear interpolation between two quaternions (which represent orientation).

[Werner]

That is unfortunate.    Animators don't have time nor technical interest to do a CHOPS conversions, just to quickly smooth out gimbal rotation errors.

 

I will look into this and submit a RFE.

 

Thanks guys.

 

Werner

 

ID=71716

Edited October 15, 2015 by Werner

[amm]

In Houdini it's called Spherical Linear Interpolation (slerp), and is generally available in CHOPs, though I'm not sure if this is something available in the channel editor. Houdini, Maya and Softimage all use the same mathematical technique for rotation interpolation, which basically boils down to linear interpolation between two quaternions (which represent orientation).

 

There is qlinear() function in Animation Editor, but, as far as I know, no way to emulate something like this, which I believe is SLERP of two neighboring SLERPs. Of course, underlying math is most likely the same in Softimage, Maya, Max, Blender and Houdini - but it seems that first four apps have some functionality, not allowed in H Animation Editor. TCB on top of LERPs functionality was, most likely, first time introduced in Max, around 1996.

Anyway thank you for direct contact.

[Mandrake0]

i'm not a animator but it look like some lines of python can solve this: https://www.sidefx.com/docs/houdini14.0/hom/hou/Quaternion#slerp

could be done in a Shelf tool with a keyboard shortcut.  

[amm]

i'm not a animator but it look like some lines of python can solve this: https://www.sidefx.com/docs/houdini14.0/hom/hou/Quaternion#slerp

could be done in a Shelf tool with a keyboard shortcut.  

Imho (now I'm not coder), good candidate for Python could be original question - Euler Filter , as an single, 'do and forget' action. For TCB over SLERP, which is an alternative that many animators don't like, in 2015, when free app like Blender already have a nice implementation, one could expect an appropriate, fast feedback in H Animation Editor, not only a final result - which I'm not sure how Python can do. My personal 'solution'  was, simply to take look, at animation transfer possibilities between Blender and H, or Maya and H - 'enough good to do not animate in H' in first case, excellent in second.

[dedeks3000]

Filter Euler Rotations of Selected Channels :  
The Euler filter fixes bad rotation interpolations that happen when animating rotations using Euler angles over large angles. A common issue is the rotation flipping the wrong way between the keyframes.

To apply the filter, select any handles on all 3 rotation channels and apply the filter. The filtering operation is applied to all the channels that have a selected handle and it affects the whole channel. The Rotation Order on the object node affects the filtering operation.

The filter should only be used on rotation channels. Rotations from multiple objects can be filtered at the same time.

 

 

Lucky guy!!!

[old school]

H15 has added an Euler filter for rotate channels. Check out the gear menu in the channel editor pane.

[Jason]

While old school above addresses your question better, I think the Transform CHOP does Euler Filtering on the fly by way of the Use Rotation Hint parameter, doesn't it?  It's not documentated that way, but I think it prevents z-flipping by analysing adjacent time slices.

[amm]

While old school above addresses your question better, I think the Transform CHOP does Euler Filtering on the fly by way of the Use Rotation Hint parameter, doesn't it?  It's not documentated that way, but I think it prevents z-flipping by analysing adjacent time slices.

I think question is about 'direct' animation, full of fast changes and small user's interventions, where nodal setup really doesn't fit, nicely (even entire setup is created by machine). Another small problem with Houdini CHOP is, that they are another layer, not really controlled by Animation Editor, so not enough transparent to know, what's going on - even if user feels familiar with CHOPs. For small comparison (if I remember correctly), in early versions, 3ds Max had separate display and control of their 'controllers' for applying noise or sound effect over key framed animation, but this was melted in just one display, later. Similar is with Blender.

When it comes to procedural animation, quaternion seems to be most elegant solution, maybe a sort of direction constraint, imho. One shouldn't bother with eulers, anymore.

Anyway, nice for H to have this Euler Filter thing, already present in many apps around - at least, as an eye opener, for what else is needed.

[jonp]

Yes!  I've used the transform CHOP before for exactly this... and I discovered it by accident.

 

While old school above addresses your question better, I think the Transform CHOP does Euler Filtering on the fly by way of the Use Rotation Hint parameter, doesn't it?  It's not documentated that way, but I think it prevents z-flipping by analysing adjacent time slices.