Howdy all, we've been chatting about Houdini grooming over on Discord and I thought I'd revisit it. Coming from Interactive Groom I've got a few questions about what the intended Houdini workflow is.

As far as I can tell you more or less can't change anything upstream from a Guide Groom. How do pros set up their grooms to work around this?

For example, say I'd like to make a few changes to what I've got so far here. On the left, I want the short hair to fill in closer to the part, but I can't change the density mask since I've brushed the hairs a bit. Should I add another Hair Generate, and then another Guide Groom if I want to change that, etc, etc? On the right, I want to adjust the waviness in a Guide Process, but I've got a Guide Groom after it making some tweaks to the curve around the chin. If I change the waviness I lose the sculpting.

I'm left feeling that you have to plan the groom perfectly from the beginning, otherwise you'll have to either redo tons of sculpting or you'll have to stack dozens upon dozens of nodes. I'm sure I'm missing something and I'd love to learn more!

I stick to grooming in 18.0 since you can recache strokes with the guide groom

Yeah, I definitely prefer 18. This happens every time I try the new system. I'd still be curious to hear from people who like this workflow and are successful with it. Enlighten me!

Personally, if I know I'm working on a groom that will require a bunch of manual shaping, like your example, I generate all my guides with the guidegroom sop. In otherwords, I don't input any pre-scattered curves into it. There are plenty of great tools built into guidegroom for scattering and removing guides or increasing / decreasing density.

I've done grooms professionally and typically I'll have a single guidegroom sop for each section of the groom at the top of the chain, which generates all the guides and does the bulk of the work. After that will be all the procedural bits (frizz, etc). Once I'm satisfied I might add a final guidegroom as the very last node for a bit of cleanup. To me, having multiple guidegrooms feeding into each other throughout a network is a hard no, and I doubt the intended workflow.

If you prefer to feed the guidegroom pre-scattered guides then you just have to accept that if you need to add or remove density you'll be doing it with the brushes, which is a breeze anyways, especially once you get fast with the radial menu.

Any attribute masks I paint on the geo (density, length, etc) I really only use to affect the actual hair generation, so they aren't influencing my guides in anyway and can repaint them as much as I want to tweak the final hairs.

Honestly it took a bit for me to adjust but I absolutely love the new groom tools. Grooming in general in Houdini is by far the best I've used, and once you factor in having all of SOPs at your disposal it's simply unmatched.

Excellent, thanks so much for your insights. You've inspired me to keep trying!

Something I want to add that I maybe wasn't super clear about is that I use the absolute minimum amount of guides possible to describe the shape / flow of the groom. In your example, I would say you have far too many guides for that hair style. I'm not saying don't use lots of guides, I'm just saying only place guides if you absolutely need them. I just find it easier to manage / sculpt when there are less.

This may be an old habbit I haven't gotten over from legacy XGEN (pre-interactive) but the way I see it is, most of the 'look' of the hair will come from the clumping and guide processes used on the final hairs (like how you'd use the modifiers in xgen) and the guides are just for, well, guiding the hairs in a general direction.

I typically start with very few guides (draw or plant brush (single mode)) with a large influence radius to block out shapes and flow. As the hair starts to take shape, I will incrementally increase guide density (plant brush (scatter or single)) while lowering the influence radius as much as I can while still retaining full coverage. The benefit of adding guide density iteratively is that all the new guides you place will follow the flow of the previously placed guides. Just like sculpting, big shapes first, then work towards smaller details.

And again, as long as you keep your work to a single guidegroom at the top of your chain (at least per groom section) you can easily erase/add/redo guides all you want.

This is what a typical groom object looks like for me. Pretty simple as the majority of the guide processes are in the hairgen object.

Thanks for the follow-up. I admit that my second attempt went very badly, haha. But I thought about your suggestions and tried again, happy to say I'm actually getting results now! (Edit: this is so fun, updated the pic with more refinements.)