Howdy! IIRC prior to H16, the hair' thickness could be controlled with a texture-map or a paint node. I looked around in H16 to do the same, but can't figure out how to do it or if it's even possible at all.
Am I missing something or was this feature left out when H16's new hair system was implemented and was it a simple unintended omission or a planned decision?

You know, acting like a mult. for the ramp? No one? Sheist!

The Hair Generate Object's Thickness tab and parameters are currently the way to do global hair thickness settings.

I don't see this feature so you are correct that there is no way to set thickness via a texture map. No idea if it was planned or not. Please submit an RFE if you will with a few cases where you have used this in the past or need for the future.


Digging in a bit…

If you use the tree to go inside the network (there is a dive target that takes you inside a subnet to do the groom btw) you can find the Attribute Wrangle SOP called “set_width” that creates the standard float “width” attribute. The set_width Attribute Wrangle SOP feeds in to a Null SOP target called “Hairs”.

Looking at this design set-up, the width attribute is set directly on the generated hairs. There is no surface therefore a map would require additional logic to work on the hair.

This Null SOP called HAIRS feeds in to the dive target subnet where you can manipulate the width with any attribute type modifier SOP you wish to affect the float width attribute directly on the guides or the hair. You could fetch the surface with uv's to reference your texture map and then apply the values to the hair curves if you want.

I think that the general shape defined at the top level is a good one. If you want say whiskers thicker than body hair, you could select those whisker curves then multiply pscale with an Attribute Wrangle up. Selecting with a texture map on a surface with a value can be set up to do the same thing.
I would probably do a different groom for the whiskers my self and merge for sim if I needed to.


Remember every SOP you create inside the Hair_Generate object becomes a part of the hair generation “procedural” so you can make customizations as you go.

Hi Jeff, thanks for taking the time to write a detailed answer.
I've found the set_width wrangle, but it's way too much work to achieve that which was simple before H16. It's great that you can tinker with it, not surprising considering Houdini's philosophy but since I'm an artist that needs high level tools ready to fire at anytime on a very short notice, filing a RFE is the best thing I can do for the near as well as the distant future.
Cheers!

Oh almost forgot: is there a way/workflow to set up guard hairs like before or has this also slipped between the cracks in H16? This was a nice feature that brought some extra realism to the spheres I used to put hair on