XGen Anim wires just not working

[V4nDl0]

I am trying to put hair on an alembic cache object and then have the hair be dynamic using the animwires modifier.

I've followed tutorials that tell me this should work:

I import the alembic object with some animated motion, it has clean UVs, not overlapping.

I add an XGen description to it, choosing "groomable splines",

I do some grooming with the Pose brush, just to move the hair into a start position - I don't use any other modifiers

I add the animwires modifier, choose "create maps"

I set the density and length, generate wires, and create the map

Then I press "create hair system",

lots of curves appear in the outliner and the "Make Curves Dynamic Options" window opens

I tick all 4 options

I press "make curves dynamic" - The window closes

I press "Attach Hair System"

I press play and the blue output curves move around, attached to the alembic object and reacting to movement dynamically

If I try to update the preview for the primitives, I get this error :

"Error: XGen:  Live mode is enable but the reference frame wasn't read yet"

Sometimes the XGen preview looks OK, like the primitives are following the wires, but if I try to render a sequence, I just get a mess of stretched hairs that are attached to the frame1 position at one end.

Also, if I save the file and re-open it, I get slightly different results, the preview no longer works and the hairs never follow the wires - same error appears about Live Mode

I am using the student edition of Maya 2018, installed last week

Any help greatly appreciated, thanks in advance

[sean.heasley]

Hi @V4nDl0

There was a similar post issue to this in this thread that was solved!

The solution from that thread was:

"Check to make sure the UV's are not overlapping. If they are, some of the follicles will fail to follow the surface.

When you add a dynamic system via the animwire modifier, it's not XGen adding the nHair system, it just calls for it to create an nHair system based on what surface the description is bound to, using curves derived from the description and modifier settings."

I know you said your UVs aren't overlapping but you may want to double check and make 100% sure that they aren't.

There also is a known issue with animwires getting wrecked if the model is moved away from 0,0,0 position.

[sean.heasley]

Hi @V4nDl0

 Michael Todd also has a great breakdown in this thread on what sounds like a similar issue!

I'll post his steps from that thread here:

Couple of things you need to do...

First, you need to make a copy of the scalp geo then move the geo that XGen is bound to out of the group:

Then make a blend shape deformer with the copy in the group as the target so that the scalp geo that XGen is bound to deforms to follow the grouped geo, Select the copy then the bound geo when making the blendshape.

Then you should ideally get rid of the rigid body collider for the bound geo and make a new one for the grouped geo. It's advisable not to have a hair system bound to a shape that it is also colliding with, it can cause popping at the base of the simulation curves.

the reason the hair was not following the mesh was that XGen could not see any transform on the mesh as it was animated in a group. Using a blend shape ensures that the animation is propagated through to XGen

You might want to set the animation evaluation to DG rather than Parallel in settings and preferences as the Blend shape deformer and parallel eval may not work well together.

Please let me know if this helps or if you need any more assistance!

If one or more of these posts helped answer your question, please click Accept as Solution on the posts that helped you so others in the community can find them easily.

Kudos are greatly appreciated. Everyone likes a thumbs up!

[sean.heasley]

Hi @V4nDl0

I'm just checking in again to see if you need more help with this. Did the suggestion I provided on Friday work for you?

If so, please click Accept as Solution on the posts that helped you so others in the community can find them easily.

[V4nDl0]

This still doesn't work for me, after hours and hours of trying. I cannot get the Xgen description to move around with the animated mesh. I managed to overcome the original error of "Error: XGen:  Live mode is enable but the reference frame wasn't read yet" by making sure "update preview automatically" is turned OFF when the animwires modifier is applied and then turned back ON after the hair system is attached.

But now, I have dynamic hair, attached to a scalp which falls down and reacts to gravity - but whatever I do, I cannot seem to get it to move with the character. I've tried attaching the scalp geo to the character with blendshapes like you recommended, also wrap deformers, and parenting to joints, and no matter what - the hair stays behind. Either the geometry moves off, leaving the scalp part with the Xgen hair at the origin, or the bind of the character breaks and all the joints wander off, leaving both the scalp geo and static character behind. 

This happens with any scene, any geometry. 

I've tried the simplest scenes with just a sphere - I've tried on multiple different computers and nothing works. What am I doing wrong?

Thanks

[sean.heasley]

Hi @V4nDl0

Did you read the rest of that thread that I linked in the above post? Did none of those suggestions help?

Also, you might want to try updating to Update 5 of Maya 2018 and then try the steps again.

[V4nDl0]

Hey Sean,

Thanks for replying so promptly. I updated to Update 5 like you suggested and followed the steps again.

It sort of worked! It's just completely unstable and seems like random luck whether the Xgen follows the animwires or not.

If I keep clicking "update preview automatically" off and on again and press play, sometimes it works, sometimes it doesn't. It seems to help if I let the animation play and turn 'update' on while it's playing, then rewind to the start.

If I save the scene, it instantly breaks and the scalp geo moves around on it's own, leaving the hair and the character at the origin, but sometimes I can add modifiers and adjust settings for 10 minutes and everything works fine... and then just randomly stops again. If I load up a saved file, it's usually broken but flicking "update preview" on an off a few times can sometimes get it working. Adding colliders also breaks it. 

It's gratifying to see it working, even a bit, but in this unreliable state, it's not really usable for production. I'll try it on work computers tomorrow and see if that's any better, maybe it's my graphics card or a hardware issue?

but thanks for your help so far.

[sean.heasley]

Hi @V4nDl0

Glad to see it's almost working!

It definitely could be a GPU issue so you'll want to make sure your GPU driver is the same as our certified hardware list.

You can find our certified hardware list here!

Also please let me know how it goes on your work machines!

[sean.heasley]

Hi @V4nDl0

Just wanted to check in to see how things were going. Did changing your GPU drivers help at all?

If your issue is resolved, please click Accept as Solution on the posts that helped you so others in the community can find them easily.

[Anonymous]

Hi

I am also working on tiger. I have created the groom and applying the anim wire. On grid at static pose it's working fine. But when I give blendshape with animated alembic fur doesn't work properly. It gets stretch and the SIM doesn't work at all. I am stuck with it. The alembic body is away from grid. Can someone help me on this