I export from Daz as fbx with the options in screenshot 1:

Then I use "Advanced" in Transformer and Change from Cloth to Hair. (It actually does the same thing with Cloth, though.)

Then I use the Pose option from top menu:

And Select a pose where the shoulders are moved like Standing_04 on Left and the Hair becomes distorted around the neck/shoulder line.

Okay, so looking at this I think the problem is physics weighting.  As I always say, anytime hair comes below the shoulders you will need physics to make it drape properly.  Another way of looking at it is that with just body weighting there's no way it can transform correctly "up the line" -- just think about it, how could it possibly know what to do with that hair other than to drape it as it has?

So create a physics map for it and let physics handle it (if you still have issues, adjust the collision shapes in the shoulder).  I would do it for at least one of those hairs but I'm in the middle of something I can't otherwise stop, but if you're still having trouble with this later tomorrow let me know and I'll give it a shot).

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Mike "ex-genius" Kelley

Ok, so I did the weight maps and that did help, but in order to get rid of the distortion at the neck/shoulder line, I have to run the animation until the hair totally loses it's shape and looks all limp and stringy. (It looks even worse from the front :-)
The below screenshot is what the Bronwyn looks like in a relaxed pose in iClone before running the animation, and below that is what it looks like after running. I did the weight maps using the UV maps as shown in your video here: https://www.youtube.com/watch?v=aKPzP-dcYWU which is a great video, by the way.
I know long hair is an issue in iClone, so there might not be a good solution.

I have a strong opinion about hair.
Regardless of the hair type (long, short), it always must be weighted 100% to the head bone.

All hair I bought on the marketplace are weighted to multiple bones. That is wrong.
Let's take a look at one of the RL SWAM hair (SWAM by the way is a popular DAZ hair artist).
Anyway, a BeachClub Hair.

Look at the screenshots I made, where difference is clear. The Accessory Hair (all accessories weighted 100% to a single bone - head in this case)
was converted from the original SWAM hair and is only driven by physics and body penetration is prevented by collision shapes.
Imperfection of the original SWAM hair is obvious, I do not even have to highlight anything.
Small imperfections in converted Accessory Hair is caused by conforming routine. Conforming is another *thing*, which should never be applied to hair. It only messes it up.
For different characters, hair should be tweaked by smoothly editing hair mesh to prevent sharp twists cause by conformation. 

The physics weight map, physics settings and animation are identical for both - Default SWAM Hair and its converted counterpart - Accessory.








Couple of words about hair weights (bone weights) in CC3.3.
It is not possible to weight 100% to any bone. CC thinks it is smarter than me and whenever I apply my custom weights to hair in Blender and return it to CC, the original weight is restored :crazy:
Working with weights in CC for dense mesh is also a pain.
Things like applying 100% weight to a single bone takes couple of seconds in Blender. In CC it might take hours (if it ever finishes without crashing!).
So I could not keep this hair as a *hair* type and was forced to convert it to accessory.

Update: I forgot. In Blender, if you weight paint the very end of hair strands to the neck or spine (does not matter), then CC would accept it and would not restore original weights.
That would not cause any distortion because the strands end would be painted white on Physics map, thus completely override bone influence. This would allow to retain the hair as a Hair type.

Thank you so much for your reply. I agree that if they would just weight the hair to the head bone it would solve most of the issues with long hair. (I'm not a programmer, so I don't know the reasons why they wouldn't.) Are you saying you were able to apply physics to the hair as an Accessory?

Are you saying you were able to apply physics to the hair as an Accessory?

Yes, I was. Again the only difference between cloth and accessory is, that cloth is weighed to multiple bones varying the influence, while accessory is weighted to a single bone.
Otherwise, apply physics to accessory the same way you apply to cloth. The physics weight map might require tweaking. But in my case with SWAM hair, I did not even have to change anything.

When I bring the hair in as an Accessory or convert it to an Accessory, I no longer have the Physics tab. Is there a special way to apply the Physics?

Physics tab in CC is mostly irrelevant. It is there for reference only, as you can't even test/preview simulation here.
But when you convert hair with physics to accessory it does retain physics. Guess it is just a minor inconvenience, though it should be fixed at some point.
iClone, is where you should be working with physics.

I woke up early this morning and figured I'll try to test again Skin Weights for hair in CC (specially Miranda mentioned some enhancement related to skin weights in v3.31).
Guess the enhancement was only related to Quick Replace (suppose it is weights transfer from other asset?).

To assign the value of 1 to head bone for the selection of about 65K faces for BeachClub Hair took about 1 hour. Same takes 2 seconds in Blender.
Optimization is due..

I kind of solved the issue that I was having.  My issue - With the 3.4 update, When you apply the hair weights using this new option


And try and export over into blender to adjust weights, on import back into CC3 it reverts the weights back over.
So, I think I found a way around this:
Normally if you select the hair only and go to export "selected content"

it would save out the .iHair or .iCloth and that can be applied to other hair/cloth content using this method>

 When you attempt to do that now, with the new hair, it saves a different type of file out. It now saves out "iClone rHairElement" - 
First file is new hair file name when you export the hair from CC3
Second is the old file name

I luckily found an old file I had saved once and applied that to my new hair I made and now when I adjust the weights in blender and import back into CC3 it does NOT revert the weights and keeps my customized settings and I can save the hair like normal.

I'm not sure why this fixed the issue but it did so I'm happy. 
If anyone is interested in this work around please reach out and I can send you the file that can be applied to the hair if you need one.