LightWave 3D 8 Texturing phần 9 pdf

Chapter 18 ··········································· Part 6 Corona The Corona filter produces the same type of effect as the Bloom filter, except that it gives you more control over the look of the effect by offering more options. The Input Channel drop-down list allows you to specify a particular internal render buffer that the effect will be applied to, while the Input Threshold value determines the threshold level of that input after which to apply the effect. This is the biggest difference between the Corona filter and the Bloom filter, since Bloom is applied to pixels in all the buffers. This basically allows you to apply the effect to only one particular aspect of the surface, such as its specularity or its reflectivity. Clicking on Input Channel gives you a rather long list of internal buff- ers from which to choose. Color uses the actual raw hue of the pixels to determine which areas are affected by the effect, so that the brighter colors will bloom. Alpha uses the brightness values of the render’s alpha. Specular Shading uses the specu - lar shading values as an input, so that the areas with higher values of specularity bloom, while Diffuse Shading uses the Diffuse channel’s shading. These two shading options are different from the Specularity and Dif - fuse input types in that the shading values vary across the surface, from 0% to 100%, while the Specularity and Diffuse options take their input values directly from the values assigned in the Surface Editor and are therefore uniform across the surface. Essentially, this means that when using Specular Shading or Diffuse Shading (which are influenced by the lighting in scene), the bloom effect will appear where there are brighter spots of specular or diffuse shading on any particular area of a surface, while using Specularity or Diffuse will apply the effect to any surface that has a specularity or diffuse value in the Surface Editor that exceeds the input threshold as a whole. 392 Figure 18-9 Figure 18-10 ····································Image Filters in LightWave Effects Processing Geometry uses the normal angles of the object’s surface to trigger the effect. This is an incidence-based (Fresnel) effect, where an Input Threshold value of 100% places the blooming on areas that face the camera directly. Inverse Geometry is the opposite, whereby the normals that are perpendic - ular to the camera (in other words the edges) trigger the blooming effect when using an Input Threshold value of 100%. The following image shows the Geometry option on the left and the Inverse Geometry option on the right. Special Buffer uses the Special Buffers feature in the Surface Editor as the input for the effect. This is useful for applying the effect to specific sur- faces only. For more information on using the Special Buffers feature, refer to Chapter 5. Mirror and Reflectivity use reflection information from the surface as the input. Although similar to the Specular Shading versus the Specularity input options we looked at a moment ago, the Mirror and Reflectivity options differ in that Mirror uses the flat reflection value assigned to the surface in the Surface Editor, while Reflectivity uses the reflection shading information. The Shadow option uses shadows on the surface to trigger the effect, while Shading uses the actual light on the surface as the input. So the Input Threshold value determines how brightly lit an area of the surface must be before it blooms. Depth applies the effect accord - ing to the z-depth buffer, using the values of 0% to 100% to represent the transition from black to white in the buffer. Velocity uses movement of the object as a trigger. Luminance and Transparency use the appropriate values set in the Sur - face Editor as the input for the effect. You can mask the blooming effect using one of these buffers as well, by selecting it from the Threshold Mask drop-down list. 393 Figure 18-11 Figure 18-12 Chapter 18 ··········································· Part 6 This buffer now acts like an alpha channel for the effect. The mask can also be inverted. The Effect drop-down list gives you three different blending modes for the effect. The Additive mode creates an effect that looks extremely hot (white), where blooming pixels are closely grouped. This is useful for effects like heated metal. This mode cre - ates an effect that is very strong in the middle and much less so on the edges. Normal (the default) is similar to, although not quite as strong as, the Additive mode, since the effect at the center and the edges tends to grow more evenly, as opposed to being concentrated in the middle only. Maximum takes the maximum of contributive pixels, creating a strong bloom effect where the blobs of light on the surface actually tend to merge where they meet one another (most noticeable when the Size value is set fairly high). Figure 18-14 shows each of the different modes, with all other settings the same for each. From left to right we have Normal, Additive, and Maximum. The Falloff drop-down list allows you to select an option for how the bloom effect falls off (at its edges). Refer to the little preview window to see how the different Falloff options work. You can achieve some really bizarre effects by playing around with this setting. The Linear falloff type simply has a straight falloff in the bloom effect, from solid white in the middle to fading away com - pletely at the edges. Smooth produces a slightly tighter effect, with the falloff occurring sooner from the middle, while Center Bias creates an even tighter falloff from the middle. Figure 18-16 shows the Smooth falloff on the left and the Center Bias falloff on the right. As you can see, they are very similar. 394 Figure 18-13 Figure 18-14: Effect options Figure 18-15: Linear falloff ····································Image Filters in LightWave Effects Processing Solid Box causes the blooms to appear square and Ring forms halos of light instead of blooming spots. In Figure 18-17 the Solid Box falloff is shown on the left and the Ring falloff on the right. Just as we have in the Bloom filter, the Strength value is the strength of the Corona pixel compared to the source pixel and the Size value is the radius in pixels of the brush at a 640 x 480 resolution. If the resolution is dif- ferent, the brush is adjusted so that the effect always looks the same. Use the Edit Texture option to add color and modulation to the effect using a texture, which can be a procedural texture, an image, or a gradient. Clicking on this button opens a Texture Editor just like we find in the Sur- face Editor, where you can create layers of textures. 395 Figure 18-16: Smooth and Center Bias falloff Figure 18-17: Solid Box and Ring falloff Figure 18-18 Chapter 18 ··········································· Part 6 When using gradients with the Corona filter, you’ll find some unusual input parameters that are only found when using them with this particular filter. The Previous Layer, Depth, Dis - tance to Center, and LW_Corona Input Channel options allow you to alter the way in which the Corona effect is applied to the surface. When the Texture Only option is active (checked) and there is also a tex - ture color, the effect uses the value of the texture only. The Corona filter will be added to your alpha channel when the Contrib - ute to Alpha option is selected. Use the Save Effect to File option to save just the corona effect to a separate image file (or image sequence) when render- ing, and select an appropriate file format in which LightWave should save the images. And that’s it for the Corona filter. Since it offers so many more controls than the Bloom filter, you will probably find that it can take a little longer to set up, but the results often have a greater effect than using Bloom. Use Bloom when you need a quick and easy overall effect, and Corona when you need to limit the effect to certain aspects of the surface. Soften Reflections This filter creates soft-looking reflections by simply blurring them some - what. It is a faster rendering option than using the Reflection Blurring option in the Surface Editor, which greatly impacts render - ing times. Take a look at Figure 18-21. The logo in the back - ground has Soften Reflections applied to it (using the filter in conjunction with Special Buffers, discussed in a moment), while the logo in the foreground does not have the 396 Figure 18-19 Figure 18-20 Figure 18-21 ····································Image Filters in LightWave Effects Processing filter applied to it. Notice how the reflections in the front logo are sharp, while the reflections in the back logo are softened by the filter. The filter is simple to control, since it only has a few adjustable options. The Softness value controls the strength of the effect, while the Blending mode determines how the effect is applied to the surface. The Replace mode (the default) replaces the original rendered reflec - tions with the blurred pass, while Average calculates an average percentage between the original render and the blurred pass to create a more subtle effect. Maximum takes the maximum of the replace result and the original value to create a slightly lighter effect to avoid any dark halo around the reflection. Alpha uses the alpha channel of the surface to blend the effect, while LumaBlend blends according to the intensity of the actual reflection. You can use the Scale By Surface Buffer option to use the effect of the filter together with surfaces using the Special Buffers feature in the Surface Editor. This limits the effect so that it only affects surfaces using Special Buffers. For more information on using this feature, refer to Chapter 5. 397 Figure 18-22 Chapter 19 Creating Hair and Fur with Worley Labs’ Sasquatch This isn’t texturing, is it? Well, no, strictly speaking, hair and fur are render- ing affairs, but since they are intrinsically linked to surfacing as a whole, I thought it would be good to have some coverage of an excellent hair and fur solution for LightWave, Worley Labs’ Sasquatch plug-in. Sasquatch is a very vast and powerful plug-in, and to really discuss it in depth would require an entire book, but we’ll take a cursory look at its uses here. 398 Figure 19-1 ························Creating Hair and Fur with Worley Labs’ Sasquatch Effects Processing NOTE: LightWave ships with a limited version of this plug-in, called Saslite. For the purposes of this chapter, we will be looking at the full version of the plug-in, as it contains all of the Saslite options as well as a host of other controls for creating great-looking hair. Adding the Plug-in to Your Scene Once you have installed the plug-in, Sasquatch works in Layout as a displace - ment on your model, and as a pixel filter for the rendering stage. To assign it to a partic - ular layer in your scene, you simply open the Object Properties window (press p) and assign it to the Add Displacement list under your Deform tab. To open the plug-in’s control panel, double-click on the Sasquatch name in the list. The initial panel that opens can be quite daunting at first! Be warned that this is just one of nine such panels. Sasquatch, like G2, comes with a superbly written manual, so there is no need for me to go into every one of these options here. Sasquatch Features at a Glance Let’s look at the shading options of the hair. The Shading panel in Sasquatch contains a number of settings that you’ll find familiar, since they are very similar to the surface attributes that we deal with in the Surface Editor. 399 Figure 19-2 Figure 19-3 Chapter 19 ··········································· Part 6 The Diffuse, Specular, and Glossiness settings work much the same as their standard surfacing counterparts in the Surface Editor. Use the Diffuse setting to brighten or darken the hair, and use the Specular and Glossiness values to determine how shiny it is. Taking the latter two values up very high will give the hair a wet look. The Specular Tinting option works like the Color Highlights option we have in the Surface Editor — it tints the specular highlights with the color of the surface. The remaining controls on the Shading panel give us options for con- trolling how light affects the hair. You can place hair on the model using a number of different options. You can apply hair to the entire model, you can apply it to a certain surface, you can attach it to guide chains (splines) that you model, or you can use weight maps or alpha images to determine where it appears as well as how it looks, in terms of density, coarseness, etc. Using weight maps is probably the most interactive way of controlling short- to medium-length hair, and is my favor- ite way of using Sasquatch. Simply create a weight map in Modeler for whichever attribute you want to control, such as Density, Coarseness, Length, etc., and use high weight values to specify higher values of that attribute or lower weight val - ues for lower values of the attribute. Density also acts as a method of actually determining where the hair will appear. For example, if you were creating a weight map for Density, you would make the areas where you want a lot of hair a very bright orange in the weight map, and where you didn’t want any hair at all you could leave those areas green, or even make them blue. Once you use a weight map within Sasquatch, you can determine how those values are then taken into account when the hair is rendered. 400 Figure 19-4 Figure 19-5 ························Creating Hair and Fur with Worley Labs’ Sasquatch Effects Processing To give the hair color, the Color panel offers a number of controls for us to play with. You can set basic color options here, as well as determine how the color changes along each strand of hair and how the color is randomized through the hair, so that it is not simply a single, unchanging color (which looks very unnatural). You can also apply mapping to your hair in the Mapping panel. This allows you to use either an image or a vertex color map to color the hair. Very handy indeed! Sasquatch comes with a number of demo files that demonstrate each of these options. Apart from shading options and mapping options, Sasquatch offers a vast array of styling tools and dynamics tools as well. While the plug-in can take some time to fully master, it is easy to get started, and since it provides such a great hair solution for LightWave, I highly recommend it to anyone who is serious about character work, since hair is such an important part of that facet of 3D. Visit Worley Labs’ site at www.worley.com for more information about Sasquatch, as well as demo files, a gallery, and tutorials. 401 Figure 19-6 Figure 19-7 [...]... and change the color to cream Figure 20 -8 4 08 · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · Metal Surfaces Quick Tutorials 12 Select the green car paint surface, right-click on it, and select Copy Select the cream car paint surface, right-click, and select Paste Then change the cream paint surface RGB values to 240, 2 38, 1 98 13 Check the Double Sided option for the... 4 09 Chapter 20 · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · Part 7 be an incidence-based gradient, so select Incidence Angle as the Input Parameter for the gradient 17 Select the top key that has been created on the gradient ramp, and change its Value to 60% Create a key at the bottom of the gradient ramp now, at 90 .0, and change that key’s Value to 20% 18 Now... what I am doing so that I can see all the contours of the model, as shown in Figure 20- 18 413 Chapter 20 · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · Part 7 Figure 20- 18 I copy the layer with the screen shot and increase its contrast until it is pure black and white Figure 20- 19 I then change the blending mode of this layer to Screen This makes all the black areas... well, so that some areas have slightly stronger specular values Figure 20- 28 Figure 20- 29 23 Copy the scratches layer from the bump map, and place it above the layer you just created Adjust the brightness of the layer (Image>Adjustments>Brightness/Contrast) so that the scratches are a very light gray (not white, but close to white) 4 19 Chapter 20 · · · · · · · · · · · · · · · · · · · · · · · · · · · · ·... might want to consider switching the radiosity off or changing the quality of the radiosity to speed it up Figure 20- 38 423 Chapter 20 · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · Part 7 Your render should look something like Figure 20- 39 Figure 20- 39 If you find that the reflections or specularity has come out a little too bright, simply adjust the Layer Opacity... is overwhelming and tends to look really CG 7 Select the top key on the gradient ramp that is automatically created when you create a gradient layer Change its Value to 45% 8 Now create a new key at the bottom of the gradient at 90 .0 (you can tweak this with the Parameter value to be sure) Change the Value of this key to 5.0% This gradient now makes the surface 5% reflective in areas that are directly... on areas of the surface that slope out of our line of vision, this being 90 º We are now finished with setting up the basic parameters of the green paint However, the paint still doesn’t look quite Figure 20-4 right yet 407 Chapter 20 · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · Part 7 9 Go to the Shaders tab and load the BRDF shader 10 Double-click on the shader’s... want these to look like giant scratches in the surface, just very shallow abrasions on it 18 Copy the text layer that you made earlier, and place it above the scratches layer Change the color of the text to 157, 157, 157 This is so that the text will appear slightly raised on the surface of the pistol Figure 20-27 19 Next, copy the brushed layer that you created with the motion blurred noise and place... brushed grain to the underlying layers This will help 4 18 · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · Metal Surfaces Quick Tutorials to create some texture to the bump map so that the metal does not appear totally smooth 20 Your bump layers are now complete Save a copy out as a file to use as a texture in LightWave 21 Now we move onto the specular layers Create... “car paint green” surface Set up the surface values as follows: Figure 20-2 RGB: 13, 36, 6 (this should be applied already) Diffuse: 80 % (This lower value prevents the surface from becoming oversaturated when we apply reflections to it.) Specularity: 100% Glossiness: 80 % Reflection: Leave at 0% for now, as we will use a gradient for this later 3 406 Leave all the other values as they are, as shown . where you can create layers of textures. 395 Figure 18- 16: Smooth and Center Bias falloff Figure 18- 17: Solid Box and Ring falloff Figure 18- 18 Chapter 18 ··········································· Part. while the logo in the foreground does not have the 396 Figure 18- 19 Figure 18- 20 Figure 18- 21 ····································Image Filters in LightWave Effects Processing filter applied to it Surface Editor that exceeds the input threshold as a whole. 392 Figure 18- 9 Figure 18- 10 ····································Image Filters in LightWave Effects Processing Geometry uses the normal angles