DynaWave User Manual

Tutorial 1: Simulating an odd shape falling into the water
We will start by creating a water surface. Create a cube and quad divide it 2 times. Then select the top faces and then quad divide them 3 more times. Your cube should look like the one in the image. The next step is to flatten the cube somewhat and stretch it around. After doing that, click on the axes icon in trueSpace to make the axes visible. Move the axes up until they are aligned to the top faces of the cube. This is important since DynaWave will determine the position of the water surfaces depending on the axes position. Click on the axes button again and you are done. You may want to save this object so you can use it again later. With the water surface created, you can now open DynaWave and press the Select Water button so that DynaWave recognizes your object. Now we will create an object to drop into the water. Go to top view (make the water invisible or move it out of the way while we model this object). Draw a boomerang shape similar to the one shown in the picture and then sweep it. You want the object to be quite thick as shown. This object will not affect the water surface if it does not have some effectors in it. So lets create some. Press the Create effector button once. A sphere-like object with pointed tips will be created. This is an effector. All effectors have a spherical influence independent of the geometric shape, so try to keep them undistorted so you can see at all times the spherical influence they will have on the water surface. Scale the effector and place it in the center of the boomerang. Make sure you center the effector in the front view as well. If your effector does not fit perfectly don't worry. Even if it sticks out of the shape it will not be visible either in the simulation or at render time. Cover the boomerang with effectors by copying the original and moving it around and scaling it appropriately. Near the ends of the boomerang the effector will be too small to cover the height of the boomerang, so make a copy of this small effector and place two of them one on top of the other as you can see in the picture. At this point, if you look in the Effectors panel you will see something like the image below. If not, press the Refresh button once. The objects in the scene are listed and have a checkmark next to them. DynaWave will automatically enable all objects whose name starts with 'Effector'. You can use your own spheres or use DynaWave's effectors for this purpose, but you must have them checked in this list so they interact with the water. You can even select a group of objects to be active effectors by using the Select by Name button. A very important detail is that all effectors must have a different name so that DynaWave can recognize them. If you make copies of grouped objects you might end up with effectors whose names are the same. To solve this problem you can press the Refresh button. This will find any duplicate names and rename those objects so that all are different. In some rare cases even after pressing Refresh a couple of times you still have duplicate names. You will have to rename those objects by hand, but it is a rare occurrence. The next step is to group the effectors as sibling. Then select the boomerang object and group the effectors to it as child. By grouping them this way you ensure simple organization that will allow you to adjust the objects later and will enable you to animate the group together. Make your water object visible again and/or move it to the center. Move the boomerang so that it is above the water surface. Then go to frame 20 and move the boomerang down so it is under the surface of the water. Play the animation so you see the boomerang along with all the effectors move below the water surface. Set the step value at the bottom of the interface to 1 or leave it at the default 2. The step value determines how many frames get processed. The lower the step the more precise but the slower the simulation will be. A step of two will process every other frame. A value of 3 will process every 3, etc. The minimum value is of course 1. I would not recommend going past step of 2 unless the conditions of the simulation allow it, or if you just want to see a quick preview. Then press the Start button. You will see the boomerang fall into the water and the water will react to it by creating ripples and waves conforming to its shape (thanks to the effectors). You can let the animation run till the end of the 100 preset frames or press Stop (or the ESC key). If you want to continue the animation you can, by pressing the Continue button. If the Record Keys box was checked, your water surface object will now have a vertex animation which you can playback by pressing the Play button in trueSpace. If you want to change the colors or any aspect of the water surface, press the Delete animation button, do your changes and then press the Select water button again so DynaWave acknowledges the new water as your starting object. If you do not re-select the new water surface, DynaWave will revert to the old one you had selected at the beginning. If you would like to render the animation you may want to make the effectors invisible so that they do not stick out of the boomerang at render time. You can do it manually or just press the Hide Effector Objects button. Press the Show button to see them again. Lets now try to make a wake with our object. First go to frame 0. Move the boomerang so that it is near one of the edges of the water surface, as in the image. Now go to frame 20. On the top view align the object so that it is in the same position as it was in frame 0 (see above). Then go to side view and move the boomerang down until half of it is under the water surface. Go to frame 60. Move the object all the way to the other side of the water surface. The motion path should look like the one in the picture. The next step is to adjust the amplitude. In general, when making wakes, you want to tone down the amplitude since ripples accumulate and can produce big waves. Set the amplitude to 0.2. Press the Start button and watch. The simulation will get progressively slower as it goes. This is due to the fact that DynaWave has more ripple events to compute and keep track of at each subsequent frame. Also, notice how the object seems to be ahead of the wake it is creating. This is a delay caused by the way DynaWave computes the wakes. To avoid such effect we can use a trick. At frame 0, go down the hierarchy of the boomerang object so that only the extruded object is selected (not the effectors). Then move the object back so that the effectors lead the object by half the size of the bigger effector in the front (see image). Go up your hierarchy again. Press the hide effectors button so you can see things clearly. Press the Start button and watch how it works now. As you can see we have managed to put the wake infront of the boomerang by having the effectors lead the way. Congratulations you have made your first water wake! Lets try something interesting now. Press the snow preset button. Notice how all the water dynamics parameters changed. Set the amplitude to 0.15. Set the life span to 100. Press the Start button and watch the effects. Instead of a wake we now have a trail! Interesting possibilities, don't you think? The scene for this tutorial is saved as Tut1.scn.

Expand your mind!

Copyright 1998-2000 by Alain Bellon. All rights reserved.