Hi all,

I have not used Houdini in some time, but hopping back in for a project and could use some tips.

I remember reading about adding secondary motion to fur without simulation a while back. I do not recall the article, but I've been looking for tutorials or anything that might cover this topic.

Is this possible to do in Vellum, or maybe somehow CHOPS? I recall one of the VFX studios did not simulate much of their fur and used something like CHOPS (I think, please correct me if I'm wrong).

Thank you for any tips or pointers to tutorials!

Alex

Hello,

A possible way to do this is to use CHOPs for adding lag/jiggle on curves, then blendshape this with oeiginal fur animation using curveu attribute.

Try doing this :
1. Animate curves, for example by using Guide Deform SOP with deform by skin mode
2. Apply a Channel SOP on positions to use lag/spring/jiggle CHOPs in a chopnet
3. Morph/blendshape between curves before and after Channel SOP, you can use a remapped curveu attribute or any other attribute you want for masking the blendshapes

check fabio hair system, include sims with chops already, after that just make for each line point the normal to the next point in curve, and attribute transfer that attribute to the body of the character for the fur direction attribute

ObeidaZakzak
Hello,

A possible way to do this is to use CHOPs for adding lag/jiggle on curves, then blendshape this with oeiginal fur animation using curveu attribute.

Try doing this :
1. Animate curves, for example by using Guide Deform SOP with deform by skin mode
2. Apply a Channel SOP on positions to use lag/spring/jiggle CHOPs in a chopnet
3. Morph/blendshape between curves before and after Channel SOP, you can use a remapped curveu attribute or any other attribute you want for masking the blendshapes

Thank you very much! I will try this method out.
Much appreciated!

pelos
fabio hair system

Thank you, I found the tutorial online and looks promising!
I appreciate the help!

Hi again,

I managed to get guides deformed by a sphere, and I get the concept of adding lag/jiggle, etc., to guides, but I can not seem to get the CHOP network applied to the guides in the guidedeform node.

Any tips? Apologies, but I am definitely rusty using Houdini. This is an interesting concept though!

Thanks!


I'm waiting for my Houdini install at work, so I'm using Apprentice at home.

Can't find out why it's not working in your scene, there should an issue in node path configuration somewhere between guidedeform node, chopnet and channel sop.

Here's an example of how to do this in SOPs, you can try out Lag, Spring and Jiggle CHOPs with this example. A Blend Shapes SOP is added at the end so that CHOPs motion applys only over curveu's profile.

EDIT : also added a Guide Process SOP at the end to get back to initial guide length, because morphing between animation and CHOPs makes guides lose/gain length.

ObeidaZakzak
Can't find out why it's not working in your scene, there should an issue in node path configuration somewhere between guidedeform node, chopnet and channel sop.

Here's an example of how to do this in SOPs, you can try out Lag, Spring and Jiggle CHOPs with this example. A Blend Shapes SOP is added at the end so that CHOPs motion applys only over curveu's profile.

EDIT : also added a Guide Process SOP at the end to get back to initial guide length, because morphing between animation and CHOPs makes guides lose/gain length.

I will check the paths you pointed out. Everything seems correct.

Thank you for this scene! This is exactly what I was looking for. The Lag, Spring, and Jiggle CHOPs can be really useful and I see background characters at least getting this sort of treatment.

Thanks again!