For some sections of my groom I have been using the guidegroom nodes to manually shape the hair. Now I have applied the hair to an animated version of my model, the guides which use a guidegroom node do not update their location along with the animation.

Using the recache strokes button updates the guides location to be correct for the current frame. Is there a way for me to automatically rechace the strokes for each frame? Or is there something I have missed along the way?

To note, he parts of my groom which only use the procedural hair nodes work successfully when using an animated subject.

Any help would be greatly appreciated.

That's to be expected. Guide groom isn't meant to be animated as it relies on a stroke cache stored in the space of the guides.

As a work around, compute a local space delta and transfer it to the animated guides, and reorient the delta into the new space.

jsmack
That's to be expected. Guide groom isn't meant to be animated as it relies on a stroke cache stored in the space of the guides.

As a work around, compute a local space delta and transfer it to the animated guides, and reorient the delta into the new space.

Thank you very much for the reply, this is all a huge learning experience. Would you mind elaborating a bit more on this workaround? At the moment I don't really know how to go about computing local space deltas.

Or use a guide deform, that's what it's for.

Do your groom on the static model, then a guide deform transfers your groom onto an animated model.

Groom goes to the first input, static model to the second, animated model to the third.

mestela
Or use a guide deform, that's what it's for.

Do your groom on the static model, then a guide deform transfers your groom onto an animated model.

Groom goes to the first input, static model to the second, animated model to the third.

Thank you for the reply. If the model im using is already animated, do you know a way to turn it into a static model which will be suitable for the second input?

s024059h

mestela
Or use a guide deform, that's what it's for.

Do your groom on the static model, then a guide deform transfers your groom onto an animated model.

Groom goes to the first input, static model to the second, animated model to the third.

Thank you for the reply. If the model im using is already animated, do you know a way to turn it into a static model which will be suitable for the second input?

You need the original model before animation.

“Static” in this context is the “pose” at which your groom is created. That might simply be a frame zero (or 1) or could be a timeshift from the animation, depending on what you are doing.

Marc

Working! - Thank you all for the help.

Is this method still working in Houdini 21?

Currently attempting a groom and after plugging my guide groom (fresh scene) into a guide deform (groom 1st input, static model 2nd input, animation 3rd input) the guides stayed in place and didn’t move with the animation. Does anyone know why this might be and if there’s a fix?

LwrCartwright
Is this method still working in Houdini 21?

Currently attempting a groom and after plugging my guide groom (fresh scene) into a guide deform (groom 1st input, static model 2nd input, animation 3rd input) the guides stayed in place and didn’t move with the animation. Does anyone know why this might be and if there’s a fix?

It should still work. Is this at the Object level or in SOPs? Are there any errors or warnings? If you do a blendshape between your static model and your animation does it work without scrambling the points? Have you tried a guide skin attribute lookup on your guides before the guide deform with the static skin as the second input?