Kristinka Hair 2.0

izze
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Re: Kristinka Hair 2.0

Post by izze » 11 Jan 2011, 01:43

Thank you again for your help. I missed the sample scene. Sorry.

Cheers

j3st3r
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Re: Kristinka Hair 2.0

Post by j3st3r » 03 Feb 2011, 14:12

A question, is it possible to UV map the resulting mesh?

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Mathaeus
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Re: Kristinka Hair 2.0

Post by Mathaeus » 03 Feb 2011, 14:44

Of course :)

I think it's explained a few post above. There are a few compounds just for that.
Basically there two methods:
1. compound called 'Set UVs On MT Extrusion' (or something similar). First you set some UVs on MT extrusion, then ICE node re-arranges UVs. This one is working on stripes only.
2. compound called 'Create Cylinders From MT Extrusion', that fits the mesh into one or more vertical cylinders or stripes (according to subdivision count), so you an set UVs in your own way.

Plus a few 'utility' nodes for 'sticking' mesh to Point Cloud (if mesh is frozen, so there is no Helge's operator on it anymore), reverse of that, depending on what you need.

For now, limitation is that point cloud need to have 'uniform' strand array, same count of segments for each strand (no 'Optimize strand' , node), also, once the mesh is frozen, Point Cloud should keep the 'topology' - same count of points and segments, as well as same topology on mesh . Nodes were built on simple, but relative fast math (modulo, divide by scalar, so on), that does 'remapping' of IDs from strands to mesh, or reverse.

Cheers

j3st3r
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Re: Kristinka Hair 2.0

Post by j3st3r » 03 Feb 2011, 16:02

Sorry guys the queston, but I have to solve urgent issues, and that's why I'm asking. Technically I'd like to make hair with Kristinka for games, using poly strips.

The next question is that how I use the collision mesh? I have guide hairs that penetrates into the head of the character....


Thanks!

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Mathaeus
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Re: Kristinka Hair 2.0

Post by Mathaeus » 03 Feb 2011, 16:31

'collision mesh' name, is actually a heritage from some early versions. In a few last versions, no one node is using this. However, there is a chance you can find compound called 'Push strands outside geo' (or something like...) in Helge's stuff (Melena or MT-strands..). As name says, this only moves strands outside of *closest* polygons.

If interpenetration happens only on hair filler, and you're using Follow NURBS node on guides, probably you can fix this by moving 'Split on Y' slider at bottom of PPG.

Good luck

j3st3r
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Re: Kristinka Hair 2.0

Post by j3st3r » 03 Feb 2011, 22:01

Thanks I need it...unfortunately I couldn't found the above mentioned compound....

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Hirazi Blue
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Re: Kristinka Hair 2.0

Post by Hirazi Blue » 03 Feb 2011, 22:11

The link to the last "known" version of the MT_StrandNodes addon can be found in this thread
This addon contains the "Push Strands Outside Geo.xsicompound" Mathaeus mentions above...
;)
Stay safe, sane & healthy!

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Mathaeus
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Re: Kristinka Hair 2.0

Post by Mathaeus » 03 Feb 2011, 22:30

Jester,

if you could describe a bit more what actually happens, would be nice. Effect of mentioned compound depends on closest surface. If strands are somewhere in the middle, there is a chance segments will 'spread' all around. Btw, 'Test collision with surface' inside 'Strand dynamic framework' is pretty much the same thing.

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a few questions

Post by fjg » 07 Feb 2011, 23:20

Polystrips - I've been playing with the extrusion compounds for a while, but I'm having trouble setting up the uv's on the extruded geo. Does anyone have a tut, or ice tree they could show? I'm interested in the strips of poly's rather than the cylindrical, but any help would be great.
I'd ultimately like to rendermap (or ultimap?) kh hair to a low poly mesh, or the extrusions themselves - has anyone done this? my maps come out all black (but that may be my error on setting up those ops...)

Density - I noticed the remap uv's for emitter mesh. is this how you guys are getting density for hair at the hair line on forehead (in the hair test thread)? I know there is a way to use something like this or fcurve for controling density (rate?). I've set the density controls on the emit hair compound and I can increase the density around the forehead, but when looking straight on at a character, its scalp is still visible. how many strands are being emitted in the girls hair on bottom of page 4 (anto's)?

Thanks for sharing this set of compounds! its great stuff.

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Mathaeus
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Re: Kristinka Hair 2.0

Post by Mathaeus » 07 Feb 2011, 23:56

hi there

- uv on poly strips: I think simplest way is just to freeze mesh, apply (to mesh) node called 'Create cylinders from MT extrusion' (actually it creates the straight strips too, name is a bit stupid), freeze it again, create your UVs, then apply node called 'stick MT extrusion to point cloud' - this will fit the mesh back into original shape

- render mapping, probably you need to set distance to surface to something higher than distance from mesh to last 'hair' - if you're rendermapping the emitter (head)

- for hair 'interface' line, a 'nice' way is to gradually delete some strands ('kh delete points', driven by weight map on emitter, plugged into 'execute on emit' of kh Emit Hair. However, girl on page 4, that's just erased in post (hair was rendered in separate pass)

- about 30k hairs for girl on page 4, about 70 segments.'Rendering weight' is count of hairs * count of segments, so long hair costs much more. Together with small rendering strategy (fixed 32 pixel tile size with rasterizer, pre-rendered FG map, fixed rendering 'depth' level to about 20 , otherwise MR falls into lovely 'trace additional FG points', forever). Hopefully you can use 3delight now.

izze
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Re: Kristinka Hair 2.0

Post by izze » 17 Feb 2011, 21:39

Hello Mathaeus, I have been using your hair tools a lot recently and have come across a problem I cannot seem to figure out. When strand length is controlled by a weightmap, the strands seem to get cut, and I loose the taper set by strand size in SI units. Is there any way around this?

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rray
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Re: Kristinka Hair 2.0

Post by rray » 17 Feb 2011, 22:14

Strand thickness depends on the absolute distance traveled from the strand's root (That is, unless I'm missing something)
So with this setup it should be ok that hair gets cut that way. Does using the normal Strand fCurve (which uses relative distance traveled) does what you want? This one shouldn't depend on the absolute distance traveled, but would set thickness depending on %age along the length of the strand.
I hope I'll also be able to use KHair in a while again!
softimage resources section updated Jan 5th 2024

izze
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Re: Kristinka Hair 2.0

Post by izze » 17 Feb 2011, 22:34

Yes, the normal Strand fCurve seems to work fine. Thank you. For some reason I thought I had to use the fCurve in SI Units to keep the thickness constant when changing camera distance. I am still a little (very) confused on this point.

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rray
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Re: Kristinka Hair 2.0

Post by rray » 17 Feb 2011, 22:55

Tickness has to be in SI Units and length in percent units in your case. Luckily it works together!

Btw I found Anto's approach to keeping thickness constant produces better render results than using the built-in "AbsoluteStrandWidth" attribute
softimage resources section updated Jan 5th 2024

izze
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Re: Kristinka Hair 2.0

Post by izze » 17 Feb 2011, 23:10

I was never able to produce strand taper using Anto's Strand Screen Size In SI Units. SEE That is why I stuck with the ShapeSizeAbsolute method. I am sure I am missing something simple. And it has been explained several times in this forum. But, I just cant seem to get it.

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rray
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Re: Kristinka Hair 2.0

Post by rray » 17 Feb 2011, 23:58

That's weird I just rebuilt the tree exactly like your screenshot, and the tapering works. Could it be that there's some weird multipliction factor in your fcurve?

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