Kristinka Hair 3.0 released

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Kristinka Hair 3.2Author: Anto Matkovic
The July 2014 update is another big one introducing new nodes like »Fit NURBS«, »Curls advanced«, »Curvature Amplifier«, »Grouping in Form« »Follow CurveList« »Stretch Hair« »Hair Filler Rounded« — for a full description see the si-community thread and the updated documentation.

The Kristinka Hair toolset is a new and unique way to set up, style and simulate hair using ICE nodes. A set of fully customizable ICE nodes Scalable, from only a few basic compounds for building basic hair, to very complex structures. Hair styling that always considers the whole shape of the hair. Styling works well for short and for long hair. Unlimited hair length, unlimited number of hair segments. Automatic, procedural generation of details - always with full control. Locks, clumps, curls, turbulence, are created by ICE compounds Additional modifiers, like cutting hairs by external geometry, constant strand length for key frame animation, resampling and subdividing strands, morphing with another hair, modulating hair's distribution over emitter, so user can increase density on most visible areas Full support for the Sofimage's built-in Strand Dynamics Framework simulation engine. Only factory ICE nodes were used, it should work nicely with any Softimage version from 7.01 on.

Other media available: Version 3.1's online 'first steps' tutorial. si-community user Bronco67 has created a video introduction for an earlier version available here. Also: A rendering tests thread, a TV ad by PsyOp featuring Kristinka Hair.

In case you want to apply kH3 nodes and dynamics on top of strands that were not generated by kH3 itself, here is a setup to enable that.

local backup: kristinka_hair_32_02july2014.rar

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Mathaeus
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Re: Kristinka Hair 3.0 released

Post by Mathaeus » 06 Mar 2013, 00:02

izze wrote:Hey Mathaeus,

Can I ask you about fur vector by null? I have been creating my null vector field and constraining the nulls to the mesh for animation. Now I have an animation where nulls cross over each other and the influence gets effected. Is there a way to bake or set initial state for vector field on a deformed mesh? Thanks.
Hello Izze,

well, nulls are supposed to stay around static emitter. After that, everything is deformed later, by "deform hair" node or something else, using deformed copy of emitter mesh. This deformed copy don't need to carry any tangent map, ICE tree or like.

About crossing, there is a bit more precise version of "deform hair" in attachment - this one uses a mix of polygon reference frame and point normal. Should be just a bit slower than original "deform hair" (which uses only polyref frame for delta), but still with nicer interpolation, without effect of faceting - but with a small chance of flipping at very high angle between polygons of deformed mesh. That is, as long the mesh is used for deformation delta, this mesh should be deformed smoothly.

If you want to experiment:

There is also in attach, an example for baking the "vector field" into vertex colors - just in case you want to live without nulls, at some point. Might be faster too. It wants some switching procedure, baking goes to vertex colors of (yet another ...) copy of emitter, using ICE tree on this mesh, then it needs to be frozen. This is, because baking back from point cloud to emitter, is dependency cycle. Then in ICE tree on Point Cloud, you can replace the emitter, also to call vertex colors as vector field. This is a bit old school method, today I think it's possible to use attribute instead of vertex color - but lovely switching procedure is still here. Anyway don't forget to change vertex colors to float (in PPG of vertex colors).


deform hair by orientation

izze
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Re: Kristinka Hair 3.0 released

Post by izze » 06 Mar 2013, 01:26

Ah ha. I understand now. Thank you so much!

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Re: Kristinka Hair 3.0 released

Post by izze » 27 Mar 2013, 17:14

Ok, I finally finished grooming and animating my little furry character. Now I was trying to render with simulation effects. I cannot seem to get simulation to work with Deform Hair setup. The strands no longer follow my deformed mesh. Is simulation with deform hair possible?

Here is my test scene

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Re: Kristinka Hair 3.0 released

Post by Mathaeus » 27 Mar 2013, 21:15

izze wrote:Ok, I finally finished grooming and animating my little furry character. Now I was trying to render with simulation effects. I cannot seem to get simulation to work with Deform Hair setup. The strands no longer follow my deformed mesh. Is simulation with deform hair possible?
Hello Izze,

As you said, this node isn't that smart. It's meant just for following the deformed polygons, that's all. I definitively need to talk with that ignorant (that is, me) who put it into "simulation" folder.
Unfortunately, there is no anything really streamlined in kH stuff, when it comes to simulation. In these almost four years of this pack on the road, as far as I know, successful simulation with kH nodes, belongs to people who already are able to create the similar system. Remote advice didn't worked, too.

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Re: Kristinka Hair 3.0 released

Post by izze » 27 Mar 2013, 22:16

Ah, ok. Still the best hair system out there. Thanks again for coming back to answer all my questions.

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Re: Kristinka Hair 3.0 released

Post by adrencg » 28 Apr 2013, 03:06

Hey Mathaeus, I was looking at year old post from the Luxology forums...

http://forums.luxology.com/topic.aspx?f=9&t=68706

How did you get the ICE hair from Softimage? I know point oven will work on Regular Softimage hair, but not on ICE strands.

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Re: Kristinka Hair 3.0 released

Post by Mathaeus » 28 Apr 2013, 12:52

adrencg wrote:Hey Mathaeus, I was looking at year old post from the Luxology forums...

http://forums.luxology.com/topic.aspx?f=9&t=68706

How did you get the ICE hair from Softimage? I know point oven will work on Regular Softimage hair, but not on ICE strands.
Hi,
I,ve exported curves via MDD, not strands. Curves were generated by Fabricio Chamon's Strand to Curves addon. ICE generator was a special ICE point cloud, generated from original one. I think there's "kH Clone Point Cloud" node or something like, under "shading" folder of kH3. Basically it choosing every nth strand of original point cloud, then makes a clone. This makes some kind of guides for hair in Modo.
However, with all that conversions, where only guides are transferred, imho it's close to impossible to get 1:1 result, especially with something created in open system like ICE. All data related to interpolation is lost, that it is. Also, at least in Modo 601, Modo hair system looked like something created with short hair/fur in mind. If I'm correct, interpolation was always influenced by orientation of polygons of subdivided mesh - not played nicely with long hair.
BTW, next export to try, even I don't know how hard is to do it, for now, it's for Blender Cycles.
Tried this one, and I'm very impressed by quality, even reasonable speed for path-tracer. Unfortunately doesn't support motion blur, yet.

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Re: Kristinka Hair 3.0 released

Post by adrencg » 28 Apr 2013, 17:05

Mathaeus wrote:
adrencg wrote:Hey Mathaeus, I was looking at year old post from the Luxology forums...

http://forums.luxology.com/topic.aspx?f=9&t=68706

How did you get the ICE hair from Softimage? I know point oven will work on Regular Softimage hair, but not on ICE strands.
Hi,
I,ve exported curves via MDD, not strands. Curves were generated by Fabricio Chamon's Strand to Curves addon. ICE generator was a special ICE point cloud, generated from original one. I think there's "kH Clone Point Cloud" node or something like, under "shading" folder of kH3. Basically it choosing every nth strand of original point cloud, then makes a clone. This makes some kind of guides for hair in Modo.
However, with all that conversions, where only guides are transferred, imho it's close to impossible to get 1:1 result, especially with something created in open system like ICE. All data related to interpolation is lost, that it is. Also, at least in Modo 601, Modo hair system looked like something created with short hair/fur in mind. If I'm correct, interpolation was always influenced by orientation of polygons of subdivided mesh - not played nicely with long hair.
BTW, next export to try, even I don't know how hard is to do it, for now, it's for Blender Cycles.
Tried this one, and I'm very impressed by quality, even reasonable speed for path-tracer. Unfortunately doesn't support motion blur, yet.
You're right...Modo Fur is just for fur. Long hair doesn't work that well, especially styling.

I can't remember if I asked this before, but is there a way to use Kristinka and have splitting of regions between collision object, like the shoulders. Is there was to define areas that are not interpolated so that you can get hair regions that separate from each other?

I thought about learning Blender. How are you liking the interface improvements and Cycles?

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Re: Kristinka Hair 3.0 released

Post by Mathaeus » 28 Apr 2013, 21:15

adrencg wrote: I can't remember if I asked this before, but is there a way to use Kristinka and have splitting of regions between collision object, like the shoulders. Is there was to define areas that are not interpolated so that you can get hair regions that separate from each other?
yeah you're already asked :), so answer again:

- generally, hair is interpolated along NurbS surfaces, splitting goes in between them. I'd believe, provided samples show of this as well. There are ways to do splitting inside area of single NURBS surface, like in "follow_nurbs_offset" samples from pack.

- there is no public available node for automatic hair splitting, according to some external geometry. Shouldn't be hard to create something along this line, but I don't see anything close to user friendly, easy understandable setup.

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Re: Kristinka Hair 3.0 released

Post by adrencg » 29 Apr 2013, 17:28

When looking through the Kristinka example models, I noticed that the Syflex sim separates the hair based on the strips. That's exactly what I needed.

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Re: Kristinka Hair 3.0 released

Post by Mathaeus » 30 Apr 2013, 10:50

adrencg wrote:When looking through the Kristinka example models, I noticed that the Syflex sim separates the hair based on the strips. That's exactly what I needed.
Well, great if you needed this, not reverse :). This separation is some kind of workaround, actually it keeps the distance to guides, which was before attaching to mesh stripes. If not, there's chance to intersect with collision geometry, let's say if two guides are on opposite sides of shoulders. Otherwise I'd really need to write some kind of automatic splitting.

By the way, *if* you'll be playing with this stuff more, maybe it's good to know, that, technically, hair splits all the time, according to triangles of emitter geometry. However, by using some surface for styling, like Nurbs surface, these strips are kept together. Something almost impossible for human hand, but not big deal for machine. Structure is similar to UVs in texture editor. One strip = "chunk" in some nodes.

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Re: Kristinka Hair 3.0 released

Post by adrencg » 02 May 2013, 22:45

Is it possible you're mistaken about the MDD? I made a new set of guides with the "strands to curve" plugin. But the point oven interface won't allow a curve object to be placed in the MDD processing area.

I can export a LWO object with the exporter, and then I run the LWO to curves python script in modo to make the curves. But the curves have open breaks in the middle and are useless.

Can you make a short list of steps that you took to get those guide curves into Modo from XSI.

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Re: Kristinka Hair 3.0 released

Post by adrencg » 02 May 2013, 22:56

Figured it out...I needed to change the python script number of points to 28 instead of 14.

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Re: Kristinka Hair 3.0 released

Post by Werner » 31 Jul 2013, 12:29

Hi,

We are having a bad day with fur on one of our characters, and found the problem to be "PolygonRefFrame" that gets screwed up once a mesh has been subdivided by zbrush or Mudbox. Subdividing the mesh in xsi seems to work ok, and does not affect the poly orientations.

We use KH Deform hair and this creates a checkerboard pattern on short fur. Have a look at the sample images to see what I mean. Emitting from the low res mesh works perfectly, but once we use higher subdivided meshes from zbrush or mudbox, this pops up.

Any help regarding this would be most welcome, and I know that this might not be a KH compound problem, but rather a problem when using KH on subdivided geometry.
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Re: Kristinka Hair 3.0 released

Post by Mathaeus » 31 Jul 2013, 14:04

Werner wrote:Hi,

We are having a bad day with fur on one of our characters, and found the problem to be "PolygonRefFrame" that gets screwed up once a mesh has been subdivided by zbrush or Mudbox. Subdividing the mesh in xsi seems to work ok, and does not affect the poly orientations.

We use KH Deform hair and this creates a checkerboard pattern on short fur. Have a look at the sample images to see what I mean. Emitting from the low res mesh works perfectly, but once we use higher subdivided meshes from zbrush or mudbox, this pops up.

Any help regarding this would be most welcome, and I know that this might not be a KH compound problem, but rather a problem when using KH on subdivided geometry.
Hello,

PolygonRefFrame is used to calculate delta, between static and deformed mesh. How mesh is subdivided, what SI assumes as polygon orientation, this should be irrelevant - as long as exact copy is used for deformation. Definitively, copy should be created in SI, after all changes in topology (like subdivision, regardless where it's performed). Otherwise there's chance for all sort of problems, like different indexing. I think it's good idea to re-calculate the tangent map too, after all topology changes (kH stuff expects tangent map on static, "emitter" mesh, tangent map could be frozen).

By the way, there's a bit better version of "deform hair" node, on previous page of this thread. It won't solve this problem, but it gives a smoother interpolation. It compares orientations, created by point normal (which is interpolated, while PolygonRefFrame is not), and first axis of PolygonRefFrame.

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Re: Kristinka Hair 3.0 released

Post by izze » 30 Aug 2013, 19:06

Is it possible to get the hair tips to taper to 0 relative to SI Units? I am using Strand Screen Size in SI Units with KH2 and KH3, but get the same result. Longer strands get a longer taper.

Image

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