Exercise 14.2 Modeling for Dynamics
This exercise will show you how you can blow apart a window. The technique can be used for anything, from a creature crashing through a brick wall to a bowling ball knocking down a set of pins. The project you’ll do here will show you a quick technique for creating a window in Modeler, then how to use dynamics in Layout to crash an object through it, essentially shattering the window—another hard-body dynamic effect.
1. Open Modeler and select the Box tool from the Create tab. Create a Box in the bottom-left (Back) view, about 10m by 5m, with multiple segments. You can do this by pressing n to open the Numeric panel, then setting the number of segments. Create about 24 segments or so for the X and 14 for the Y. This doesn’t have to be exactly like it is here; just make sure your box has many segments so that it can be broken apart. Figure 14.11 shows the model.
Figure 14.11 Create a box in Modeler that has multiple segments along its X- and Y-axes.
2. If you’ve created your flat box and can’t see it in the Perspective view, press f to flip its polygons.
3. Press Shift+j to activate the Jitter tool (also found on the Modify tab).
4. In the Jitter panel that appears (Figure 14.12), enter 400mm for both the X and Y values. Leave the Z-axis setting at 0. You’re not creating any depth on the Z, as you’re creating just a flat window.
Figure 14.12 Use the Jitter tool to shake up the shape of the polygons.
5. Switch to Points selection mode at the bottom of the interface.
6. Now, carefully select the very bottom-left point of the box, and holding the Shift key, select the point immediately above it, as shown in Figure 14.13.
You’re selecting two points sequentially to tell Modeler which way you want your selection to go, for the next step.
7. So, from the Select drop-down at the top left of the interface, choose Select Loop, as shown in Figure 14.14.
8. Once you choose Select Loop, LightWave Modeler continues selecting points for you around the entire box, as shown in Figure 14.15.
Figure 14.13 Select in order,the bottom-left corner point and the point just above it.
Figure 14.14 Choose Select Loop to automatically continue the selection of points.
Figure 14.15 Using Select Loop is an easy way to select the points around the entire box.
9. With the entire outer edge of points selected, click the Modify tab, and at the bottom left under the Transform category, click the More drop-down button and then choose Quantize, as shown in Figure 14.16.
10. In the Quantize dialog box, leave all axis settings at 500mm, as shown in Figure 14.17. You can simply enter .5 and press the tab key to get a 500mm setting.
Figure 14.16
Select Quantize on the Modify tab.
Figure 14.17 Set the Quantize value to 500mm.
11. Click OK to apply the Quantize values, and as you can see from Figure 14.18, the selected points even out, except for a few.
Figure 14.18 Using the Quantize tool, you can even out the selected points.
12. Press Ctrl+t to activate the Drag tool, and then drag the few points that are sticking out of the perimeter back into line with the other points.
13. Save your model as GlassWindow or something similar. You’re not quite finished.
Note
There’s another way you could have created this model to this point. After you had created the segmented box, you could have selected all of the polygons of the model except for those that make up the outer edge. Then, apply the Jitter tool. Only those selected polygons would have Jitter applied, leaving the outer edge nice and even. The reason this exercise showed you another method was simply a way to have you work with a few more of Modeler’s tools. So, now you know.The choice is yours for future projects.
14. Switch to Polygons selection mode, and then press w to open the Statistics panel. Look to the 4 Vertices listing. Click the plus mark to its left, and all the polygons with more than four vertices will become highlighted, as in Figure 14.19.
Figure 14.19 Use the Statistics panel to select polygons with more than four vertices.
15. Taking a look at your selection, it pretty much seems that all the polygons have more than four vertices. That’s fine, and while you’re not going to subpatch these polys, go ahead and press Shift+t to triple them—which is LightWave-speak for converting a selected group of polygons into triangles. These triangles will become "shards" of glass in the shattered-window animation.
16. After you’ve tripled the polygons, click the Align button on the Detail tab. You might get a message saying that 20 polygons have been flipped. The Align tool looks at all the polygons, sees that the majority of them are facing in one direction, and flips the few other polygons that are facing the other direction (Figure 14.20).
Figure 14.20 Triple the polygons to break them up more, and use the Align tool to make them all face the same direction.
17. We have one last thing to do, and this is probably the most important step. On the Detail tab, select Unweld. The reason this step is important is because in order to have another object break apart this glass window, the multiple polygons you just created can’t be attached to each other. Figure 14.21 shows the tool. The adjacent polygons of your model share common points and side segments; in LightWave lingo, these polygons are welded together. The Unweld command converts each selected polygon into a discrete, self-contained object with sides and vertices all its own.
Figure 14.21 Use the Unweld command to disconnect all the polygons.
Applying the Unweld command to the window surface will allow the dynamics engine to shatter the window by animating each triangular segment as an independent "shard." If you did not unweld the points, the dynamics engine could only move or push the entire window object, even though it consisted of multiple segments.
Note
Even though unwelding separates each segment, the window is still one solid object.
And, without using dynamics to break up the object, moving the object in Layout will still move the entire object, not the segments.
18. After you’ve unwelded the points, save the object. That’s it! Your window is created. If you want, select various polygons and apply different surface names to them. Select a few polygons, for example, press q, and then give those panes of glass a specific name and color. Deselect, then select some other panes, surface, color, and so on.
