Hi there,

I'm trying to figure out how to use the Guide Partition SOP [www.sidefx.com] to restrict which guides influence which hairs in a SOP-level hair groom. I haven't been able to find any forum posts or examples of Guide Partition working, so I'm hoping someone can help!

I'm trying to create a basic chin-length bob hairstyle in Houdini 19.0.498. I've created a set of guides for the main body of the hair (I haven't tackled the bangs yet), and mirrored them to cover both sides of the scalp. I've also added a partition curve down the middle of the groom, to (hopefully) separate the guide influences over the two halves of the head.

Here's how the guide and partition curves look (the guide curves are colored based on root y position, and the partition curve is in white):



If I plug this partition curve into a Guide Partition SOP and then onwards into a Hair Generate SOP [www.sidefx.com], it looks like the generated hair is influenced by guides from both sides of the partition, as can be seen from the fact that there are hairs falling down inside the body of the head:



I've done the same kind of thing in Maya before with Xgen, using a region map to restrict the guide influences. Am I missing something about how the partition curves should be set up to achieve a similar effect in Houdini when generating hair? Or is this kind of guide influence not something you can configure in Houndini's hair system?

(I tried poking around inside the hair SOP HDAs to see if I could figure out what I was doing wrong, but it looks like all of the magic for Hair Generate happens within an embedded Hair Generate Core, which isn't editable, so I haven't been able to discover anything there.)

Thanks for any help!

Dave.

After experimenting with this for a while, it looks like the issue was that I'd set a rest position on the guides just before passing them into the Guide Partition SOP. Removing this Rest Position SOP made the partition start working. I still have a *few* stray hairs that fall down into the center of the head, but it looks like redistributing the guides that define the sides of the parting (by moving them slightly further away from the path of the parting line) should / might fix that issue.

Dave.

How did you get the Guide Partition to work ? I've been trying to figure it out, but I guess my brain is too small.

No matter where I put them, in the "Guide Groom" Node, or the "Hair Gen", no effect whatsoever.

Hi,

as far as I can see the parting happens in the hair generate. The Partinglines are needed with a partinglines primitve group and the attributes N, partingradius and partingstrength on the points. Check if they are on the guides.

I lost the partinglines and attributes along the way through the sims.

Good luck
Ray

I have all those attributes and still can't get anything out of the guide Partition sop, wondering if I'm doing something wrong..

I only got it to work with the static mesh. But not able to transfer it with the guide transform node. The parting line stays at the original static mesh

I put the guide partition node under the guide groom node inside the guide groom node.

I am not sure if I m doing it right. Certainnly not right cuz it doesn't work with deform and guide sim

Any one find any solution of Guide Partition..no effect at all.
How should i use it?