hair tutorial in lightwave

Creating Polygon Hair by Elmar Moelzer

Since the excellent hair- tutorial by Stu Aitken for Inside LightWave® 6 (and 7), onequestion has been asked over and over again:

How to put hair on that head?

Given a bald female head may look sexy sometimes (a la Alien3), but it does not really fitmy taste and probably not the taste of most readers of this tutorial. There are quite a fewways to do hair and probably the most popular solution is the use of Sasquatch(-light), thewonderful hair- plugin by Steve Worley. This solution certainly produces great and realistichair, but it also has its disadvantages, which are due to the nature of these kinds of plugins.Because of it being a post- rendering- effect, it does not do raytraced shadows andreflections and it does not show correctly in refractions neither. This is why I decided todevelop my own method for doing polygon- hair, based upon what I had learned from oldtechniques, but by using the new features of LightWave® 6.5+. This hair does not have thedisadvantages of plugin- hair and it could also be used as a proxy together with Sasquatch(-light) to have something that will show in mirrors and to cast raytraced shadows on thebody.

This tutorial requires solid knowledge of LightWave®s tools and is probably not to well suitedfor beginners. It requires LightWave® 6.5+ and an image- manipulation- software such asAura, PhotoShop or PSpro.

Part1: Modeler

I decided to use subpatches for my hair- strands, due to the fact that they require lessgeometry for the definition of the shapes an thus are easier to handle. The use of normalpolygons might be more efficient, which would help decrease rendertimes, but wouldcertainly increase the amount of work needed.

Modeler with the head of my still hairless "Cornelia" in a background- layer (active layer 2):

Tutorials

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Surfacing & T

UV Mapping

Modeling

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Pagina 1 di 15Creating Polygon Hair - Tutorials - LightWave 3D®

23/07/2004http://www.newtek.com/products/lightwave/tutorials/modeling/hair/

Create a flat box with 7 segments in y- direction:

Create a UV- map with the following settings:



The result is a UV- map that is nicely laid out on the UV-grid:

Now go into subpatch- mode [TAB] and use the drag- tool to modify the geometry to looksimilar to this:



This is our very first strand. The area of the hair- root may stick into the head a bit, but thestrand must not cut through the head anywhere else. You should try to have a bit morespace to the head especially on the sides. Please copy this strand into a separate layer forlater use. Now clone this strand and place the copies around half the head by moving androtating them. Take care for the strands not to cut into the head anywhere. If you like youcan modify the strands to fit the shape of the head a bit better. You do not need to payattention to the shoulders- area yet, as we will do that later on. This may sound like atedious task, but it isn't. In fact, it should not take experienced users more than 5 minutesto do this. I decided to put two strands behind the ear:



Now copy these strands into a new layer and move them down and in a bit. This will becomethe layer of hair closest to the head. In the best of cases this hair- layer neither cuts throughthe hair- layer above, nor through the head (this should be avoided at all cost). Again it mayonly stick into the head at the roots.



You can now delete the polygons that are completely inside the head:



I repeated this step one more time and placed this new copy right between the first twolayers, a bit nearer to the first one, as I still had a lot of empty space left there. This way Igot a bit more volume and I avoided holes through which one could see the head below.Basically one half of the head should be perfectly covered with hair now. If you like you cango on and add even more layers of hair, but I think that for this tutorial three will do the job.Please be aware that additional layers will dramatically increase rendertimes!

Next we will pay attention to the shoulders- area. Again we do not want the hair to passthrough the geometry of the body. If you are planing to use Skelegons for later animationwith bones, you may very well leave the hair the way it is now. For this I would suggest toleave the "wig" in a separate layer and parent it to the head- bone later on. This way I avoidthe hair- bones distorting the body by accident. The posing of the hair in Layout may be a bitmore difficult than in Modeler though. Another way of doing the animation may be by theuse of Motion- Designer. Preparation for that would be similar to the next steps, but with thedifference that one needs more space to the body, for the hair being able to "fall" down onthe shoulders more naturally. For this tutorial I decided to do the "posing" of the hair inModeler by simply dragging around points.

This is the result with all layers activated:



While I used to be pleased with the way the hair- modeling looked at this point, I realizedduring render tests, that something was still missing: Natural hair does not fall down thatevenly. In fact long hair uses to break and splice (female readers may very well know what Iam talking about). This creates shorter fibers that stand away from the haircut. What is notso loved by people, who pay a lot of attention to their perfect hairstyle, should still be ofinterest for us, for we will not want our haircut to look like being wet or fresh from thebarbers. To get around this, we need another layer of strands, which will be on top of allother layers. For this we will use our very first strand of hair (the one we copied into anotherlayer for later use), but his time we will need a lot of thinner strands, so we will have to usethe stretch tool to make it thinner. This time there is no need to pay to much attention to thehair cutting through other strands and the way they are distributed over the head. Thesefibers will be very thin and here the count is more important than the precision. You mayalso use Modelers tools to get a bit more variation into them and to make them shorter thanthe other strands.

Because of these fibers being a bit shorter than the other strands, there is no need to matchthem to the shoulder- geometry this time:



If you haven't done that yet, apply a new surface- name to every- hair- Layer. This way youcan easily select every layer using the polygons- statistics (in case you would need it lateron). Now you can copy all hair- layers into one single Layer and mirror them. Don't forget touse the DragNet (or other tools) to add a bit of variation to the other side to avoid obvioussymmetry. The result of the Modeling- part should look similar to the one displayed below:



Here we clearly see the big advantage of creating a UV- Map right in the beginning:



Yes, it is still laid out perfectly! Despite the massive deformations and cloning we did to thegeometry afterwards!

Part 2: Layout, Surfacing, and Texturing

First we will need a good texture for our hair- strands. It should look similar to the one here:



This kind of texture is easily done in Aura, PhotoShop or PSpro. I created it by stretching an image similarto the "FractalReflections"(from the LightWave® Content) in the y- axis a few times. A bit of contrast-adjustment and it was done. You may use the image on the left to complete this tutorial and as a referencefor your own textures. Because of functions differing a lot in the applications named above, I really don'twant to get into much more detail here.

This texture is then placed as an imagemap into the following channels of the hair- surfaces: Specularity (invert Layer), Transparency, Bump (invert Layer)and Diffuse (invert Layer).

The projection- type is UV. The UV- map is of course the one we did in the beginning of this tutorial. If youwant to, you can paint another texture for the color and apply it to the Color- channel, which will ad furthervariation to the hair. This is especially important to make brown, blonde or gray hair look more realistic.Because my "Cornelia" having her hair dyed red, I was able to drop that step. Basically a simple reddish



color and Color Highlights set to 50% (Advanced Tab in Surface- Editor), proved to be sufficient. Don't forget to make the surface "Double- Sided" and to turn "Smoothing" on.

Now for the rendering: I want to admit that render times can be high. You also should use Anti-aliasing ofat least Medium with Adaptive Sampling off, because of the hair- texture having a fine structure. Otherwise you might experience a Moiré- effect during animation.



Above you can see a very first test rendering (render time 6min 58 sec on a Dual 1Ghz P3 in 640 x480with Ray traced Shadows on and Anti-Aliasing High). This looks like hair, but is still far from being perfect.It still lacks Volume and there are parts where one can see right on the head below. With a bit of fine-tuning and a few more layers, it will become a very nice looking "wig" though. To get a bit more variationinto the strands I played a bit with the UV- map. I moved the UV coordinates for some of the strands andvaried their width in the UV- window. I also modified their geometry a bit to make the hair less straight and to add more variation.

This is the final result, I got after a bit more tweaking and a few more layers (6 layers in total):



I hope you enjoyed this little tutorial. For questions regarding this tutorial or LightWave® ingeneral, don't hesitate to contact me. Good luck, happy rendering and god bless!

If you'd like to contact Elmar, send email to: [email protected]

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hair tutorial in lightwave

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