the advantages of using this method:
-every render system is able to render them (unlike using plugins)
-gives the hair a ''stylish'' though realistic look, which might be the aim for some projects.
-easy to display in real time.
-possible in every application(unlike most plugins)
-takes a long time to set up.
-restyling is basically impossible, you should get it right the first time.
-much harder to animate.
In this tutorial I will be using 3dsmax, though it is possible to follow along in different applications, since it only uses basic tools.
This is actually a really important step, since it will be nearly impossible to change styles later on. For this tutorial is choose the hair from final fantasy, they used planes for their hairstyles as well. So I thought it would be appropriate to take this one, plus it's a kick ass hairstyle ;).
Setting up your scene//step2
Load the model you want to work on and place some lights around it, I chose a simple set-up with four lights around the model.
This way all sides are lighted which makes every side easier to see when making test renders (this does not have to be the final lighting set up ofcourse, this is just for testing puproses)
the important thing here is that you turn on shadows and more specifically "raytraced'' shadows, this will render shadows from the opacity map. the regular shadow will just cast a shadow from the plane itself, while raytraced shadows will also cast shadows that come from the translucent parts in opacity maps.
Now that everything is set up for test rendering, lets create some funky textures.
A single textures will be created using different brushes (explained in detail below), this will create more randomness and detail to your texture.
It is also a good idea to use multiple textures, so that not every plane gets the same texture, this will create more randomness and realism.
using just one repeating texture will look ok, but combining different layers will just give it that extra bit of realism.
In this tutorial I will be using photoshop to create the textures, but ofcourse any paint programm will do.
First a quick note about creating the brushes.
There is no rule as far as I know, simply create same random dots and use them as brush (edit>define brush preset), these will represent the individual strands of hair.
I think it's good to create 3 different brushes and combine them for your texture, to create randomness.
(It is important to set the spacing to 1% and and shape dynamics on, put the opacity and flow down when painting, but experiment with these settings)
the first brush is a global brush, this one is used to block out the basic shape.
the second brush is mostly used to create some more randomness and detail
the thirth brush is used to add individual strands of hair
In this example, using these brushes, I ended up with this result;
(It is important to test render strands of hair this way to see what works. for example I added a soft glow to create more volume to the hair, otherwise
I would get sharp edges between the planes, but this is different for every project/texture so make test render when creating your textures)
(this is the one I used for my model, feel free to use this yourself, though I suggest experimenting with your own textures)
setting up the textures in your application.There are multiple ways of doing it, depending on your application and renderer, I will just use the simple default settings, so everyone can follow along. (these steps are possible in every application). (simply put the created textures in the correct slot).
*Create a color texture using the same method as explained in step 3 and put it in the diffuse slot.
*put the opacity texture in the opacity channel.
*I also like to put the opacity texture in the bump channel, this will create a subtle depth to the strands of hair.
*create a specular texture, or simply use the opacity texture for this.
example in 3dsmax;
Since these planes will be copied a lot, it’s important to check if everything is set up alright, later on even small changes will take a lot of unnecessary time.Take a test render to see if it is set up correctly. When satisfied continue.
common problems to watch out for:
*the uv's are just a little bit to far up or down, which causes a visible line at the end of your textures. this is becaus the uv's are just a little to large and the end of the uv's then display the beginning of your texture.
*also make sure your uv's stretch far enough to the sides, otherwise it will cut your textures off and your will get a sharp edge and it will look weird :) .
There are multiple ways of going about it, feel free to experiment with it, there is no right way.
Start off with your most basic plane (the plane with the most basic textures), this will be the first layer of hair, this will cover almost everything.
The layers after this are simply to create more detail and randomness, it should look pretty good with just one layer and should cover any bald spots.
The process is simply, copy, paste, move, rotate and scale to create the desired hairstyle.
However there are some basic rules you should avoid at all times:
-intersecting planes (this will look really bad, you will get weird sharp edges in your hair)
-putting the planes to far apart, this will create bald spots.(the first part of the opacity map is alsmost "solid", make sure you next plane begins at the end of this part)
since we're going for a more realistic hair style we'll be using a lot of planes, this can get quit messy, that’s why I start adding planes at the bottom and make my way up. (starting from the top will probably give some problems, since it gets harder and harder to see what's underneath the planes).
This part will take the most time, but there is not much to explain about it, it's just a lot of moving, rotating, scaling and tweaking...
To create more detail and realism we will be adding multiple layers, meaning adding planes with other textures.
This will create a more random and thus realistic look to it.(the material for these layers is set up in the same way as the base layer).
From here on it is the same drill, rotate, scale and move the planes in position, test render and tweak.
The end result:
Hope this tutorial was usefull. Try to expiriment with different materials, settings and brushes to find out how it works and improve.