Essential LightWave 3D- P18 potx

the object. Click on the Save Motion button and save the object’s motion to a location on your hard drive. 16. Once you’ve saved the motion file, you gain the ability to adjust the speed of the simulation. Change Playback Speed to 30%. The animation will now play at one-third of its regular speed. In order to see most of the effect, we need to change our end frame from 60 to 90. Once you’ve done this, cre - ate another preview animation. The bricks now look great at 30 frames per second, but the ball no longer moves with them. That’s because we’ve only changed the playback rate for the brick wall. Let’s adjust the timing of the ball to match. 17. The motion of the ball is controlled by the Ball Hinge null object. Select this object from the Current Item pop-up menu (just below the timeline) and press <Ctrl>+<F2> to bring up the Graph Editor. Select the first chan- nel on the left, then hold the <Shift> key down and select the last channel so that all of the channels in between are Chapter 19 ······················· 498 Figure 19-26: Change Playback Speed to 30% and the end frame of your animation to 90. Figure 19-27: Scale the keys of the Ball Hinge object by a factor of 3. selected. Using your right mouse but - ton, drag a bounding box around all of the keys in the main Graph Editor win - dow to select them. Then, from the Keys pop-up menu, select the Numeric Scale option. The Scale Keys window will appear. Change Time Scale factor to 3 and press OK. The motion of the ball now matches up with our brick wall. At this point, you can continue tweaking with the animation to make it truly excep - tional. Try adding Colin Cohen’s Vibrate plug-in (available on the CD) to the camera for realistic camera shake as the ball impacts the wall. Play with the tools in the EditFX tab to alter the motion path for errant bricks (look closely and you’ll see them). Allow this introduction to HardFX to serve as a launching pad as you continue to explore LightWave Dynamics. ClothFX ClothFX is a personal dynamic that gives your object elastic qualities. You should apply ClothFX to objects that you want to deform naturally and organically. For exam - ple, ClothFX can be used to simulate clothing that stretches and folds over a character’s body. But ClothFX isn’t just for clothing. It can be used to leave footprints on the ground where a character walks. It can be used on the surface of a pond to cre - ate ripples and waves. It can even be used to simulate the motion of hair. ClothFX is an extremely powerful tool that can yield an impressive array of results. In this section, I’ll show you how you can use ClothFX to simulate clothing for your characters. Navigate to Scenes\Chap - ter_19 on the CD and load the Skirt scene. The object in this scene is a simple tube. The points at the center of the tube were extended out to form the skirt and Band- Saw was used to slice it into smaller segments. The points at the top and bottom of the tube, along with those at the point where the skirt connects to the tube, were placed into a selection set called Fixed. Finally, the skirt itself was converted into a sub-patch object. It may not look like much, but that’s the beauty of it. ClothFX can turn a ho-hum object such as this into something great. Before we begin tweak - ing the settings for ClothFX, let’s talk briefly about the scene. The tube object already has three keyframes, which give it a slight spin to its right. You should make it a rule to set up and refine your motions first, then apply ClothFX for the soft-body simula - tion. The order here is important. If you set up your dynamics first, then tweak the motion of your ················· Simulations 2: Dynamics 499 Figure 19-28: Our simulated Skirt object. object, you will have to rework the simula - tion all over again. Note It’s important to understand that ClothFX is not designed to be a “one sim for every occasion” dynamic. In other words, you can - not assign it to your character’s clothes and expect the same settings to work flawlessly in every situation. ClothFX is only a simula - tor and its results will vary depending on what you’re asking it to do. You’ll notice that the tube is the only object in the scene. Technically speaking, this vio - lates the principal law of the Dynamics Community, as there are no opposing dynamics to which this object is account- able. Under normal circumstances, we would correct this by adding a social dynamic such as Gravity. But in this situa- tion, we can avoid the extra trouble of setting up an independent Gravity object and simply use the Gravity setting available in ClothFX. 1. Bring up the Object Properties panel for the Skirt. Click on the Dynamics tab and choose Cloth from the Add Dynamic pop-up. Then click on ClothFX in the Dynamics list to bring up its settings. Note There is a bug in LightWave (confirmed in versions up to 8.0.1) that causes ClothFX to calculate parameters improperly if they’re entered in the “wrong” order, but it will cal - culate them correctly if the scene is saved, reloaded, and calculated again. Hopefully this bug will be fixed in the next revision of the software. But for now, be aware that this problem exists. If you change a setting and calculate, but are unhappy with the results and revert back to the original settings only to find that the object no longer deforms like it did before, you’re experiencing this bug. Save your scene, clear Layout, and reload the scene to work around the problem. Due to a bug in ClothFX, I cannot walk you through the individual application of each setting, but I can walk you through the group application of specific settings. And again, keep in mind that these settings are described in detail in the manual and online help system. 2. In the Basic tab of the ClothFX prop- erties, select the Fix pop-up menu and choose the Fixed/ pointset option. The Fix option allows you to choose the points that will not be affected by ClothFX. All of the points in the object except those in the skirt were added to the Fixed selection set. By choos - ing that selection set here, we are telling ClothFX to ignore the rest of the object and focus solely on the skirt. Chapter 19 ······················· 500 Figure 19-29: The default ClothFX settings. 3. Change the Spring and Sub Structure settings to 750. Spring deals with the ability of a point to move closer to or farther away from those directly in line with it. Sub Structure deals with the ability of a point to move closer to or farther from those directly across from it. (See Figure 19-31.) Increasing these settings makes it more difficult for the points of our object to move from their original positions and will help simulate a more sturdy cloth like cotton rather than a more flimsy one like silk. Note The settings used to get the “right” look for each Dynamic object are greatly dependent upon the size, shape, and number of poly - gons in the object. The settings we’re using in this tutorial will work well for this object, but they may not work for a different object. It’s important, then, to pay close attention to what each setting does. Learning the role of each setting will help you troubleshoot prob - lems in the simulation and enable you to make intelligent decisions about what changes need to be made when those prob - lems arise. 4. With Spring and Sub Structure set, switch to the Etc tab and change Grav - ity to –9.8 m. Changing gravity here eliminates our need for an independent social dynamic in our Dynamics Community. 5. Press Calculate and take a look at the results. ················· Simulations 2: Dynamics 501 Figure 19-30: Change the Spring and Sub Structure settings to 750. Figure 19-31: Spring and Sub Structure as they affect quad polygons. 6. The object now has a sense of weight (having activated Gravity) and is begin- ning to look more like cloth; however, it’s colliding with the tube object. Let’s fix this. Switch to the Collision tab and set Collision Detect to <all>. This opens up a variety of options. We can leave most of these at their default, but change Collision Off - set to 30 mm. Adjusting the offset helps keep the skirt from penetrating the surface of the tube by creating a 30 mm invisible barrier between the two. Finally, set Self Colli - sion and Double Side to <all>. This will ensure that the skirt can interact with itself. 7. Press Calculate and check the results again. Chapter 19 ······················· 502 Figure 19-32: Set Gravity to –9.8 m. Figure 19-33: Adding Collision detection helps keep the skirt from passing through itself and other objects. Adding collision detection certainly helped, but it didn’t completely solve the problem. We can increase Collision Offset to compen- sate, but there’s a larger issue here. The skirt is stretching in ways that pull the poly- gons into the tube. We need to resolve the stretching. 8. Click on the Advance tab. Increase Compress Stretch to 15000% and reduce Stretch Limit to 0.25%. Com- press Stretch limits an object’s ability to stretch. How far it is allowed to stretch is determined by Stretch Limit. 9. Press Calculate and check the results. These changes helped constrain the skirt and are keeping it from penetrating the tube sur - face, but the cloth now looks like it’s suffering from a bad case of static cling. There are several reasons for this. One is that the cloth is too heavy. When it swings around, it hits itself and gets caught in its own self-collision routines. Another is that the cloth is a little too responsive to the object’s motion. We could increase the Spring and Sub Structure settings to make it stiffer, but there’s another setting we can use to resolve this. 10. Switch back to the Basic tab. Decrease Weight to 0.1. This will make the cloth lighter and a little less responsive to the skirt object’s motion. Then increase Viscosity to 3. Viscosity oper- ates as a dampening effect, making the ················· Simulations 2: Dynamics 503 Figure 19-34: Boost Compress Stretch and reduce Stretch Limit. Figure 19-35: Change the Weight, Viscosity, and Resistance settings. motion of the cloth less severe. Finally change the Resistance setting to 0.5. This will make the cloth less resistant to wind and help its overall motion. 11. Press Calculate and check the results. Making these last few changes really helped, and our skirt is now looking much better. But it seems to be puffing out at the point where it connects to the tube object. To fix this, we can tell the Sub Structure setting to only pay attention to the Skirt surface. 12. From the Fx pop-up menu to the left of Sub Structure, select the Skirt/sur - face option. Calculate and check your results. That did it! We now have a great-looking skirt that responds well to the motion we’ve set up in our animation. ClothFX is an incredible tool and can produce amazing results. From here, you should continue to experiment and play with the settings. The more you work with ClothFX and become familiar with it, the more it will reward you with outstanding results that would be impossible to create by hand. SoftFX SoftFX is a personal dynamic that gives your object elastic qualities similar to those in ClothFX. The primary difference is that SoftFX is designed to be used on objects that need to return to their original state (meaning their size, shape, and orientation). ClothFX is not. For example, SoftFX can be used on the branches of a tree, allowing them to bend and sway in the wind. When the wind dies down, the tree will return to its original shape. SoftFX also has features that enable cyclical deformations, making it possible to automate many effects, includ- ing the expanding and contracting of your character’s chest as he breathes. Chapter 19 ······················· 504 Figure 19-36: Limiting the Sub Structure to just the skirt gives us just the look we want. In this final section, we’ll be looking at several of the options available in SoftFX. 1. Bring up Layout and load the Bendy.lwo object from the Objects\ Chapter 19 directory. The Bendy object is a simple tube that was sectioned off with BandSaw. It was then converted into a sub-patch object. It has two weight maps. One is a gradient from 0% at the bottom to 100% at the top. The other is localized to the blue sur - face around the tube’s blue center. 2. Let’s set a few keyframes to give this object some motion. At frame 10, move Bendy –200 mm to the left. At frame 20, move him 200 mm to the right. And at frame 30, move him back to 0. 3. Play back the animation and take note of the motion. 4. Now bring up the Object Properties panel and from the Dynamics tab, add SoftFX from the Add Dynamic pop-up menu. There are a number of options here, but before we change any of them, click Calculate to see what the default settings do to our object. You can see that the original motion has been exaggerated and the object appears to be bound by a large rubber band. Even when the object reaches the final keyframe, it continues to move back and forth, its motion dampening over time. As a personal dynamic, SoftFX is subject to the laws of the Dynamics Community. And in the Dynamics Community, every personal dynamic must be accountable to a social dynamic. However at this point, we only have one personal dynamic in our scene. There are no social dynamics. Only a bit of motion. Ah, but there it is. You see, motion is a social dynamic. It’s a user- defined social dynamic that every personal dynamic will respond to. SoftFX still responds to collisions, gravity, and wind, but it’s uniquely designed to respond to motion. Let’s take a look at the SoftFX options. ················· Simulations 2: Dynamics 505 Figure 19-37: Set your keyframes, then calculate SoftFX with the default settings. 5. Click on the Input tab of the SoftFX properties. Change the Motion Force setting to 500% and recalculate. 6. You can see that the object is now much more responsive to its motion. Return Motion Force to 100% and click on the Operator tab. The Opera - tor tab fine-tunes the effect of motion (or optionally wind) on the object. There are two Operator maps. At this point, the top one is set to <all>, meaning that the motion will affect the entire object. 7. The wave graphic to the left is a visual indicator of the falloff that will be applied to your object’s motion. Change the EffectSize to 0% and recalculate. The residual motion has been severely reduced and it now looks as if SoftFX has not been applied. The EffectSize setting works hand in hand with the Motion Force setting to determine the extent of the object’s reaction to motion. Change EffectSize back to 100% and change WaveCycle to 1. Calculate and check the results. The number of times the object moves after it reaches its final keyframe has been reduced. Change WaveSize(s) from 0.5 to 3 and calculate again to see the results. The time it takes to complete the motion after the object reaches its final keyframe has been extended. 8. This motion isn’t very realistic so let’s change the settings to something more “natural.” Keep EffectSize at 100% and change WaveCycle to 5. This will create more motion after the last keyframe has been reached. Change WaveSize(s) to 0.1. This will shorten the time needed to complete the resid - ual motion. Press Calculate and check the results. The object now appears to have come to a hard stop. As you can see, the Operator set - tings greatly affect your object’s response to motion. Up to this point, we’ve only affected our object’s position in response to Chapter 19 ······················· 506 Figure 19-39: The Operator tab allows you to fine-tune the effects of motion on your object. Figure 19-38: Change Motion Force to 500%. its motion. However, by using an influence map (such as a weight map, selection set, or even a surface), we can alter our object’s shape as well. 9. Click on the Operator1 Map pop-up menu and choose the Influence/ weightmap option. The Influence weight map (described at the beginning of this section) is a graduated weight map with 0% influence at the bottom and 100% at the top. Leave EffectSize at 100%, but change WaveCycle to 3 and WaveSize(s) to 0.3. Then calculate to see the results. 10. You can see that the object sways back and forth as if made of rubber. But if you look closely, the deformation is completely linear and the object appears to slant, giving it a slightly unnatural quality. What if we want the deformation to be a little more natural? We can affect the application of the deformation by applying a mode. From the Mode pop-up menu, choose Square and recalculate. Square does not refer to the shape of the motion (as in square, rectangle, or triangle). Rather, it describes the application of the deformation. Square here is a mathematical term, as in E=mc². It amplifies the defor- mation of our object by multiplying the ················· Simulations 2: Dynamics 507 Figure 19-41: Assigning an Operator map allows us to deform our object based on its motion. Figure 19-40: Creating a “hard stop” type of motion. [...]... through the use of LightWave s SasLite plug-in SasLite is the younger brother to Sasquatch, a comprehensive hair and fur simulator developed by Worley Labs The focus of this chapter will be on the capabilities of SasLite, but we will also examine the differences between it and the full version of this amazing utility Note Robin Wood is the artist who wrote the documentation on SasLite for the LightWave [8]... panel For now, just change Fiber Color to something Note I won’t be going into great detail about what each of the SasLite options does, because I’ve already covered that in the LightWave 8 documentation If you don’t yet have LightWave 8, you can find that portion of the documentation on the companion CD in the Sas Settings folder Make a 1 meter sphere in Modeler, and bring it into Layout (or simply... SasLite SasLite is a wonderful tool that allows you to add fur and hair to your objects It works as both a displacement plug-in and a pixel filter As such, you need to enable it in two different places in LightWave in order to see the effect Let’s jump right in and see how it works 1 Open the Object Properties panel by tapping , and click on the Deform tab, where the displacement plug-ins are stored . each of the SasLite options does, because I’ve already covered that in the LightWave 8 documentation. If you don’t yet have LightWave 8, you can find that portion of the documentation on the companion. pop-up. Then click on ClothFX in the Dynamics list to bring up its settings. Note There is a bug in LightWave (confirmed in versions up to 8.0.1) that causes ClothFX to calculate parameters improperly. chapter, we’ll take a detailed look at the tools needed to simulate hair and fur through the use of LightWave s SasLite plug-in. SasLite is the younger brother to Sasquatch, a comprehensive hair and