Falling Feathers Part One: Hair and Fur Effect

Over the next couple of weeks, I was thinking we could look at a couple of different techniques you might come across making your projects.  I’m not sure what its like elsewhere in the world, but in the UK (Specifically, Scotland) we don’t really have much emphasis placed on effects systems like particles and hair and fur.

Usually we have to pick up on these things alone, or from tutorials that talk about using effects to make specific sorts of outcomes and designs.  This is fine for a while, but what if you want to start designing your own effects later?  You might be left knowing how to create a really cool system, but not how to adapt it to make it bigger, smaller, a different shape, different colours, etc.

This week I’m going to introduce you to some of the uses of the Hair and Fur modifier in 3Ds Max 2010 (and possibly some previous versions).  We’ll experiment first and go through what each tool does, but ultimately we want to end up with something like this:

What is Hair and Fur?

The simplest way I can explain it is that Hair and Fur is a built in modifier that you can use to simulate semi-realistic hair, or fur.  There are a number of presets you can control, and you’ve the ability to style your hair whichever way you want (I’ll admit, this isn’t my favourite task – you’ll see why later) by using its various tools and parameters.

If you’ve watched any amount of animation online or on TV, chances are you’ve seen a similar modifier used, if not this one.  As with most of the presets, it can look pretty terrible if you don’t change anything; with some work you can get some very beautiful results.

The Process

In the image above, you can see the basic shape we’ll be working with, what it looks like with hair and fur applied as a default, and what the finished article will look like after a lot of tweaking.  Obviously while making this, I’m going for a very specific sort of white feather, but you can apply these techniques to anything you desire really – send me your results, I’d love to see what you’ve done!

Lets just jump straight in and look at what we have already.  In my scene I’ve basically created a slightly curved spline and converted it into an editable poly.  To do this, you go to the dropdown for ‘Rendering’ inside the spline’s Modify tab and select rectangle.  I set the height and width to 3, but it doesn’t really matter so long as it ends up square.  From there I modified it slightly with a taper, merged it down, and applied turbo-smooth to the whole thing (A modifier to use with caution, but I’ll get to why some other time).  This is our basic model:

Click on the modifiers list and select Hair and Fur.

After a few minutes of waiting while Max calculates where the hairs should go, you’ll be presented with the image below.  Doesn’t look much like a feather yet, in fact, if you rendered it you’d see something like the second image.

First thing we need to address is where the hair sprouts from on our object.  To do this we go to the polygon select button and select all the polys we want the hair to grow from (in this case, along ¾ of both sides).

Then we click ‘update selection’ and wait while the computer finishes working out its new calculations. (If you’re very lucky and this takes you only a few seconds, I’m jealous)

It’s better, but still nothing like a feather.  Before we do ANYTHING else, I’m going to show you how to change the colour to something a little bit nicer to manage.

Scroll down the options until you reach ‘Material Parameters’ and expand it.

Click on the current colour and change it to whatever you want; I’m going for a soft grey-white.  You need to change both the Root Colour and the Tip Colour; as a general rule of thumb the root should be slightly darker than the tip, but it depends what effect you’re looking for.

(Note about the images:  My computer decided to do something weird, and I redid a couple of steps.  My polygons haven’t actually changed from the above image, but the hairs are swept to the side.  This makes no real difference to the tutorial, just wanted to keep you updated so that you didn’t panic when I lost half my ‘hair’)

Change the values in Specular and Gloss down to something more manageable; I like to have mine around 20 and 40 respectively but it depends on the sort of effect you’re going for.  Play around with this; see what happens when you remove the gloss entirely, or ramp it up really high.  Do the same with specular.  I could sit and tell you what will happen, but it’ll stick easier if you play around and find your own way of doing it first.

After you’ve finished playing with all of that, a quick render will show you this (but hopefully with hair on either side, again, my computer decided it didn’t want to play ball =P ):

Much more like it.  What we need to do now is fix the length of the hair and style it.  You can change the length either by playing with the cut length value (scale technically works too at this stage, however it takes the whole style and shrinks it so this can make the styling tools difficult to manage):

Or by scrolling up, expanding the Style Tools menu, and clicking on Style Hair:

The orange lines you see appearing are the guidelines of your hair – they define where the hair will grow and the shape it’ll take.  The brushes and tools manipulate those lines, which in turn (combined with other parameters, some of which we’ll cover later) manipulate the hair itself and give you the finished outcome.

There are various tools in here, each controlled by the brush (which appears as a ‘tube’ in green within the viewports).  There are various settings for the brush; each selection set in the image below controls the hair by a different part.  It’s worth trying each of them out before you go any further to see what you’re comfortable using.  I use the one circled in red normally, though they all have their uses.  There’s also a scale slider for the brush (its in yellow in the image below); this defines how large an area you effect when clicking and dragging across or around the hair.  As a final note, you can ignore back-facing hairs – this is sometimes useful, sometimes more of a curse than a blessing.

You can use the following tools to manipulate your hair:

If you want to grow/shrink a clump of hair then click 1 before using the tool.

For brushing the hair into place click 2, and again click and drag the tool around on the hair until you get the finish you want (think real hairbrush but more finicky).

To cut the hair if you’ve made it too long, click 3.  When doing this, bear in mind that the tool cuts from the top of your brush guide, not the centre.

As you can see, there are other options, but aside from experimenting quickly with them a few weeks ago I’ve largely ignored them.  I may revisit Hair and Fur when I know more about those settings, but until then experiment with them on your own if you like (and I humbly apologize if, in doing so, you find an easier way to work hair and fur!).

Mistakes happen, and while initially I thought I couldn’t undo a mistake in the styling tools (which led to a lot of saves) Autodesk was smart enough to build an undo button straight into the tool itself.  The main undo button won’t work, but this one will;

At this point it’s just a case of playing around with the brushes and tools until you create a style that fits with what you want to achieve.  It’s not an easy thing to do, although the concept itself is pretty simple.  All I can say is there’s a reason I’m not a huge fan of actually styling the hair!

After some work with the styling tools on my image, this is what I ended up with:

It’s looking a lot more like a feather, but it’s still not quite right…  This is because we haven’t touched the tip and root thickness, or set up the random scale parameter.

Scroll down to the General Parameters menu; you can see a whole bunch of different parameters.  For the moment we’re only interested in Root and Tip thickness, and Rand Scale.  Root thickness defines how much of the object the hair is growing from any one hair covers, while tip thickness defines the thickness at the very end of the hair.  The fluffier you want your hair, the smaller the tip thickness value.  After playing about for a little while, I settled on a root thickness of 3, and a tip thickness of 0.5.

Next thing we have to look at is the Rand Scale parameter.  This basically defines how much of a variation you get in the lengths of your hairs.  By default it’s set to 40.0, however this is much too high for the feather.  I’ve set it to 5.0 for now, since I still want the feather to feel quite fluffy.  Here’s what we have:

The hair count default seems fine for this image, though for the human head it looks better when you’re between 45,000 and 60,000 hairs.  Just a quick point to bear in mind although its not relevant for the moment.  Another parameter you might find useful in the future is Hair Segments; this defines how smooth the finished result looks though it can eat your time up with rendering.

There are another couple of parameters you need to be aware of further down the list; Frizz and Kink.  These add body to your hair at the root, the tip, or both.  You need to play around with these and find out what combination works for you.  Usually I turn off the Frizz, but for the feather I’ve left a Frizz Root value of 10.0 and Tip value of 15.0.  The Kink parameters are 0.0 by default, though I find it useful in human hair.

Here’s our finished feather render:

Conclusion

Hair and fur is one of those tools that you can learn to use very quickly, but will have you tearing your hair out over it months later.  If you’re at all familiar with the software, you’ll know this isn’t uncommon.  All I can say is, don’t get too frustrated with it early on.  That and it can become fun later.

For now, you’ve made a feather (and spent quite a bit of time rendering it to test out what works best, right?).  With this feather, we will create a beautiful scene in two weeks (next week we need to create the particle system that’ll support it and so on, more on that later).  You can probably guess from the title what it’s going to be about!

Hope you enjoyed the first part of this tutorial, as always let me know what you think in the comments below or by email.  If you’re new here, welcome and feel free to subscribe to my RSS feed if you like what you see!

———-

Part One: Hair and Fur Effect

Part Two: Particle Systems (Basic)

Part Three: Setting the Scene

Part Four: [due 3rd Feb]

Part Five: [due 10th Feb]

Heather, the owner, started Shades of a Dream in January 2010 to help you fill gaps and increase your knowledge in 3D and Visual Effects. She also runs a newsletter; want a little extra punch? Sign up here

Heather Craik

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