Lightwave Modeling
By Mathew Duafala

Part 1     Part 2      Part 3     *Part 4

Well, After the last article you should have a pretty decent model. Now, however, we need to add the textures to make it look photoreal. There are many factors that determine whether or not a viewer will accept your creature as valid or not. After all, it is easy to make a black cat at night in a shadow, whereas a slow motion close-up of the creature passing by the camera is a job that requires the kind of talent at ILM.

If you’ve paid attention to most television horror movies, the creatures are usually shot at night or in the dark, and they are usually moving pretty quickly whenever they manage to find their way into the light. The reason is twofold. First since the viewer never gets that good a look at the creature, their imaginations can run wild. If you were to ask people coming out of a movie what the creature looked like they would all probably give you a similar but differing answer, and they would all be equally vivid in the persons memory. Secondly, since the viewer can never dwell to long on the creature itself they don’t have time to see the small imperfections that would betray the creatures CG or Animatronic origins.

With that in mind let’s set up the texturing for the creature. The first step is, since LW won’t render MetaNurbs, we will need to make it into polygons. We have two options for this, either Metaform or freezing the spline cage. We will use Metaform since it usually give equal results with fewer polygons and we can then set up the creature with the MetaMation plugin when it comes time to make it move. I’ve found that I usually only need to use a subdivision level of 1 for a decent looking model however in this case I had to use a subdivision of 2. Once that is done we need to save the polygons. I chose to save them as head_F to signify that they were "frozen". Load that object into a blank scene in LW and save the scene as headsurface.lws . I usually will have a scene for each major object's surfaces. This isn’t a problem since the objects texturing attributes are saved with the object not the scene. And since there is a scene with nothing in it but the object I can move the camera to look at it without anything getting in the way.

The next step is to go back into modeler and switch to a side only view of the wireframe. Once that is done, press the Print Screen key and that will make a copy of the screen to the clipboard. Go into PhotoShop and select File-new-OK. It should automatically set the image size to what ever is in the clipboard. Paste the captured screen. Use the crop tool to crop the picture to as close to showing the only the wireframe as possible. Then make a new layer and set it’s transparency to approximately 50%. Use the paint can to make the background pure white. Then switch to the airbrush tool and set the color to black. There should be a faint outline of the wireframe in the background. Now you can paint the bump map with the wireframe as a guide.


Fig 2

First off, I only painted the bump map for the lips in the side view. There is a reason for this that will become apparent shortly. Once you have something that looks similar to fig 2. Save as a PhotoShop document with the background deselected. Then make a new picture that is square. On this picture we will make the main bump map that will define the overall texture of the creatures skin. Use the airbrush to make something similar to fig 3. It will be necessary to make the second image tillable. To do this you need to go into filter-other-offset. Select some value so that the seams meet somewhere near the middle of the image. Then use the magic stamp tool with a soft edged brush to cover the edges. Save that then go into your LW scene. Load the two maps and go into the surfaces panel. Select the skin texture and go into the bump map panel. Use autosize with the default settings and then select the second bump map that we made. Change the mapping to cubic and antialiasing to 0.1. Repeat this process for the diffuse channel and the specular channel. Since LW uses the white areas to define the highest value we will need to change the image to Negative Image (this option is just under the picture of the image when you loaded it in. Set the diffuse and specular values to 50% and ‘high’ respectively. Don’t forget to turn on smoothing.

The reason that we are loading it into the diffuse and specular channels is really quite simple. Since we are using a bump map to try to create the image of the skin being uneven and, well "bumpy". All the areas between the bumps would in the course of the creature‘s day become filled with dirt and dust and other things that would prevent the skin there from giving off as much light, and that is what a diffuse map determines. Along those same lines of thinking, the tops of all the ridges would be "harder" and they would have more of a highlight to them, that is why we added it to the specular channel.

Go back into layout and do a test render. Depending on how large you made your image map you may need to scale it down a bit. To do this go into the surfaces and select each channel and click on the size button. This will bring up a requester and then you can simply press the forward arrow to un-highlight the number and type in a multiple (ie. 3.2m*5) and press enter.

Once you are happy with the main texture it is time to add the lips and ear texture. To do this repeat the same process as above except this time the use planer mapping along the x axis, autosized and make sure to use the same map as the alpha map also. This will ensure that the white areas of the map don’t wash out the part of the skin we have already mapped. Set the bump strength to 100% on the first map and 400% on the second. Now if you do a test render your creature should still look pretty plasticie. This is do to the default lighting in LW. Go into the lights panel and turn the diffuse lighting down to 0. Change the distant light in the scene to a point light with an intensity of 50% and move it to above the camera. Clone that light and move it to below the camera and a little back. Now do another test render. It should look much better now. Using the techniques that I outlined above you should be able to go in and start fiddling with different maps to achieve different effects.


Fig 3

Some of you may be wondering why I didn’t use any scanned image maps on this creature. If I had it would probably look a fair bit better, but I decided that since not everyone has a scanner I would use the least common denominator and just draw them from scratch. If you do happen to have a scanner then by all means use it. Find some children’s books at the local library, or in your kid’s room depending on your situation, and scan in a photo of some skin. Crop it to look as close to semetric as possible and then use the technique I gave above for making it tillable. Once you have that done then use the saturation tool to turn that saturation down to zero. This should make the picture black and white. After that use the brightness/contrast tool to turn the contrast up for the bump maps and such. Map that texture into the color channel with the accompanying maps in their respective channels and see how it looks. I think that you will pleasantly surprised at the results. The eyes on this creature are just a scan of a crocodiles eye as it was coming out of the water. The mouth is just a flat pink color with a slight vein procedural in the diffuse channel. The teeth and horns are a light yellow/beige with a small fractal bump map added. That pretty much sums it up for this portion of the tutorial. Next time I will go into how to set up a bone structure and IK.