Maya Hair Plugin - GMH2

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Mathaeus
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Re: Maya Hair Plugin - GMH2

Post by Mathaeus » 04 Sep 2016, 20:26

FXDude wrote: Hum Thanks for the info! Are strandLocation locations in world space?
Right now hairs are cloned using your "Splay" node which together with randomized strand Transforms, are then stuck back to the surface with Melena's "move strand to surface" node, allowing to define distance to clone parent in random directions also with curve profile modulation (of wavy progression) along length, so strands can be gathered up towards the tip of parent clones which are mostly themselves clones with 3-4 levels like that making clumps with wide roots made of mini-clumps.


In any event, I'm anxious (and maybe a bit scared :) ) to put out something to be tried-out!
Well there are reasons why a mix of these systems should *not* work, flawlessly. Let's say if compound relies on custom attribute, if strand array is defined in specific way, so on.
Factory nodes and kH, are considering the point position as first, root position, I think In Melena, root position is first strand, not point position - mix in this case can cause an offset of root position, or in opposite case of overlap of point position and first strand, result is NaN, which can go without visible problems in some renderers, but also can cause all sort of problems in others.
Regarding kH Splay compound, it's for use exclusively in 'fur mode', offset is along emitter surface, relative to emit location (can do overlap with long, curved hairdo), also it expects deformations to be created only by kH deform hair compound.
I think there are only three kH modifiers, *possibly* able to work without kH emitters and 'form' nodes. They are described here, I added them intentionally for use with another systems.
About 'strand location' - let's say you get it by using 'uv to location' to query the curve or nurbs surface. I think it is in world space. While some factory nodes like 'modulate by null' are in object, point cloud space, so, moving entire point cloud can cause mismatch. That's reason for keeping the point cloud on world space zero, all the time.
The renderer "turtle" used by this scene, is not currently available. The "turtle" renderer will be used instead.

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FXDude
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Re: Maya Hair Plugin - GMH2

Post by FXDude » 04 Sep 2016, 21:08

Mathaeus wrote:Well there are reasons why a mix of these systems should *not* work, flawlessly.
Which is probably why indeed some nodes don't work, so I'll be sure to include a region in the ice tree a bunch of unconnected nodes that do!

I know this duplication method is probably unorthodox, but it's what I found to reliably not change over time and to make the clones look more independent.

Nevertheless, thanks for the pointers! (and for making your great KH system happen ;;) !)

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Hirazi Blue
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Re: Maya Hair Plugin - GMH2

Post by Hirazi Blue » 05 Sep 2016, 09:39

@FXDude - if you need an alpha- or beta-tester, I am more than willing to volunteer... ;)
...

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Mathaeus
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Re: Maya Hair Plugin - GMH2

Post by Mathaeus » 05 Sep 2016, 15:12

FXDude wrote:
Mathaeus wrote:Well there are reasons why a mix of these systems should *not* work, flawlessly.
Which is probably why indeed some nodes don't work, so I'll be sure to include a region in the ice tree a bunch of unconnected nodes that do!
It's possible to create "adapters", where value of missing attribute is just replaced by something static, or, to re-calculate something , let's say ''StrandCount'' of factory or Kh nodes. But, if exact value has to be supplied ( for example, most of kH modifiers are relying on pre - calculated orientation vectors), obviously a plain static value won't be enough. At some point, there should be a design decision, which then creates incompatibilities, something works better something else is worse...
kH generally tries to keep everything in one network, it tries to have as much ''light" hair filler, it also tries to avoid any cumulative, no to so fast calculation - there are negative sides of that, like a bit more complicated structure on guides, it's not so easy (or obvious) to figure out what and how can be animated, orientation vectors are derived from external geometry. Next time I think I'll try something different, but, don't know when this is going to happen. Personally I feel a bit tired of all that visual programming things, to say honestly....
The renderer "turtle" used by this scene, is not currently available. The "turtle" renderer will be used instead.

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rray
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Re: Maya Hair Plugin - GMH2

Post by rray » 05 Sep 2016, 23:36

I looked a little into groomTools. Almost forgot, thanks for putting it to qegood use.

What might work as a workaround until some location caching is implemented is to use "uv distance" - this distance method should be more stable during animation, even if the surface is deforming. It requires that the emitter has UVs, and that the emitter is plugged into the "hair layer" node.

Two other things I discovered that could cause weird shaky behavior are:

---if you dig into the "hair layer" node, then into "interpolate guides", then at the bottom center you'll find a randomize node that has "animated" checked! this is a bug! it needs to be off! ^^

---The other thing is that the "hair emit" node doesn't like to be animated. It randomizes positions when it's called multiple times and the emitter moves. It should be possible to call it only once by adding a simulation stack and putting the "hair layer" nodes into that.

I would be best if could look at a shaky scrambly test scene and see what's going on. So applying for alpha testing too :)]
Softimage Resources section (formerly known as rray.de/xsi) updated Oct 01 2017

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FXDude
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Re: Maya Hair Plugin - GMH2

Post by FXDude » 06 Sep 2016, 03:21

Okay, let me do some minimal housekeeping (previous branch versions etc..) and I'll PM you both the scene as it is!

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