There are at least 3 methods you could use to animate hair using HyperMatter, in progressively slower degrees…

The easiest, and the fastest, would be to create ‘chunky’ hair; modelled in such a way that there are no separate strands, just a solid, but textured ‘hairpiece’.
The next fastest, would be to save separate strands as one MAX object, so that HyperMatter then treats the whole mass as one ‘lump’, but the strands still appear to move separately, although they actually don’t.

The third, and most hideously slow, but ultra-realistic, would be to make separate strands, and then apply HyperMatter to each strand INDIVIDUALLY, giving them all the ability to bump into each other, etc., but without massive processing power, this would probably take until the next millennium to get anything worthwhile (see below)…

The first step would be to make a mesh object in Max, comprising of as many strands of hair as your memory will allow. Obviously the more strands you have, the more convincing the effect, unless you specifically wanted less. 
Dreadlocks or other thick hairstyles would be perfect, as you could actually apply HyperMatter to each individual piece; the structure being relatively few items all with a fairly large surface area.

Simple long, thin cylinder objects, bent in a few places, and copied as references and copies, will soon create a fairly convincing head of hair in the short term; advanced modeling tools designed either to create hair specifically, or other kind of sinuous objects would be better for high-quality work involving close-ups.

Also remember, if you were working close-in, say for a shampoo ad that went amongst the strands that you could again apply HyperMatter to individual strands; just the ones involved in the action will do, and matte them over shots of other strands.

The most important thing to remember is that as you are effectively using real physics to describe an incredibly hard-to-model substance, memory and performance issues are very important. HyperMatter is very processor-intensive, and you really need to aim for the minimum resolution needed to do the job, as it can often be surprisingly low to produce excellent results.

So, assuming we are using the second method to produce a fast, workable demo of hair in action, you would now attach all the separate strands together to produce one MAX object, with its pivot point located at the centre-top, where it would naturally attach to the head. A simple head object will be added with rotation keys in place, which will cause the head to rock back and forth, rotating to make the hair swing around when it is attached.

The first stage of applying HyperMatter, certainly one where momentum and ‘flow’ is concerned, is figuring where the centers of mass are for objects, where you want them to swing from, etc. A little planning beforehand will enable you save time experimenting later.

So, once your head of hair is aligned and ready, you would make sure the hair mesh object is selected, hit the Create tab, and bring up the Second Nature entry in the Geometry drop-down list. There are three buttons available, HyperMatter, Walls and Record, which is greyed-out.

Select HyperMatter. The Automatic Solids panel appears with a button named Solidify Object, and a resolution spinner. This sets the resolution of the HyperMatter cubic mesh that will be applied to the Geometry. There are also 3 radio buttons labelled, X, Y, and Z Fit; these aim to produce the closest fit of the mesh around the geometry, and you would try all the options first to see which one is the most pleasing.

When you hit Solidify Object, the HyperMatter mesh appears around the object (If the object is not interacting with any other HyperMatter objects, you could reduce the resolution to much lower values for test work, and then turn it back up for rendering). 

The hair is now subject to physical laws, and as such, will instantly respond to the default gravity settings, by falling out of view when Play Animation is hit. A new HyperMatter object always has a negative Z force applied at creation, to simulate gravity.

We don’t need gravity in this particular scene, as the hair will be attached to the head, and swinging a lot, so we can disable this in the Forces rollout by changing the default value of -100 in the Z direction to zero. The hair object will now remain in place.

Because HyperMatter takes over the objects’ position and rotation data when it becomes active, you now need to use HyperMatter Constraints to impart motion to the object. Constraints are physical controls which allow you to manipulate an object using real-world concepts. 
In this example, you want the hair to be attached to the head, and use the head’s motion to create the swinging hair. The ideal constraint to use in this case is Follow, where a HM object, or part of an object is constrained to follow another MAX object.

HyperMatter allows areas of the mesh to be selected and named, and then individual or multiple constraints can be added to each part, giving total control over the object’s movement. We need the hair to be anchored down the centre parting to look natural (at least for this hairstyle, anyway). 

Make a small selection set of the mesh vertically down the parting line to about the middle of the forehead. This makes an ‘anchor’ for the hair, so that it doesn’t slip around.

The Follow constraint has different options for operation, ‘Whole Part’ means the selected area will follow the object, but is free to rotate locally with momentum. ‘Each Point’ means that every point of the selected area of the mesh will follow EXACTLY the movement of the object it is following. 
This is the option we need for the hair; otherwise it would revolve like a comedy wig, as the head rotated.

When you hit Play now, the hair will rotate with the head, at the point where you applied the constraint. As the rest of the hair is NOT constrained to follow the head’s movement, it will swing freely under it’s own momentum, producing that beautiful ‘Just Dried’ shot that we know and love so much from the TV…

Click on the image below for a high-resolution version (200K)

The most difficult part in a tutorial of this nature is suggesting what the Substance settings should be. Because an object’s parameters are so dependent on the shape and volume of the geometry you are Solidifying, and also the type of movement you want from your animation, it is impossible to suggest particular numbers. 
Different values will give different effects, like wildly stretchy hair, or really stiff wobbly hair depending on how you enter them.

One thing that would probably be common to all would be fairly high Damping values. 
Damping is the ability of a Substance to return to it’s original shape after it has been deformed; high damping means it will tend to stop fairly quickly after the force ends; low damping would leave it swinging for a long time.

The only foreseeable drawback ahead is speed of playback; because you are solidifying what could be a very high polygon-count object, HyperMatter will probably get rather slow.

In this sense it’s almost a victim of its own accuracy; because it literally is real physics involved, any objects that tend towards high-detail volume-shifting stuff or liquids will always be slow because there are so many calculations to deal with. 

However, you can use a low-res geometry object with the Geometry Manager, and then swap it with a high-res object for rendering, after you have adjusted all the basic movement, which would drastically improve performance.

Happy Styling!

Big thanks to James Biebl of Gaviota Graphics for the inspiration and original scene files for this tutorial.