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In Getting Started with Reactor in 3ds Max, Steve Nelle shows how to create realistic dynamic simulations that have objects recognize, collide and react to coming into contact with each other in 3ds Max animation projects. This course includes a detailed explanation of both rigid and soft body dynamics, reactor's various collection types, using constraints and soft body modifiers, and how to adjust and control a dynamic simulation's accuracy. Four start-to-finish projects are also included in the course, which show practical techniques for breaking objects apart, creating cloth simulations, adding rippling water effects to a scene, and more. Exercise files accompany the course.
With the rigid body elements of our scene now in place, we can start concentrating on the Soft Body objects on our simulation. We'll be using a file name Soft Body Maze01 that was saved and carried forward from the previous video. Our project's deformable objects are both found at the top of our screen. Let's zoom in a little closer, and we'll talk things over. In the introductory chapter of our title, we established the fact that deformable body objects, in order to be included in a Reactor dynamic simulation, work just a little bit differently than rigid body objects do-- that difference being that, an order for an object to appear soft and pliable, it must be placed in not just a different type of Reactor collection, but it will also need a special type of modifier applied to it in order to be put into that collection--that modifier being called a Soft Body Modifier.
Let's begin by working on the green ball. Now the Soft Body Modifier can be found and applied from a couple different places in Max. With the object selected, one of those locations would be the Animation pulldown menu at the top, going down to Reactor, then choosing Apply Modifier, then Soft Body. We won't choose that direction here. You can also find the modifier in the Quad menu, using the Shift+Alt+Right-click shortcut-- again, a direction will choose not to take.
Now if you are more custom to gaining access to the modifier through the Reactor toolbar, you can head closer to the bottom, looking for an icon that resembles a basketball with an M on its lower right-hand side. That's going to be the option we're going to use here. We'll head down the toolbar, finding the basketball, then clicking with our mouse. In the Modify column, you'll see not just the entry in the stack, but the Modifier options down below.
Now in order for the ball to show up in our simulation, we're now going to need to add the appropriate collection. In this case, that's going to be a Soft Body Collection. To create that collection this time, we'll use the Quad menu. Let's hold down Shift+Alt, then right-click. Okay, there it is up on the left-hand side. We'll choose Soft Body Collection. Let's head back to using four views, and we will run a preview to see how things look so far.
Doing a preview at this point will also give us a chance to make sure that we haven't somehow left something out of our sim object-wise. Let's go ahead and activate the preview. Again, I'll use the Quad menu. Now, from here, to play things back, we'll simply type P. Because of the number of calculations that are taking place, we may very well need to lower the number of substeps per keyframe that we're using for our simulation. Now you can do that a couple of different ways: one more temporarily and one a little more permanent.
In the Preview window, let's go up to Performance, and we'll change to 5 substeps. We'll now reset our preview, typing R, then playing things back with the P command. Things are still a little bit on the slow side, so let's change that substeps down a little lower still. Back under Performance, let's this time try 2 substeps levels. Resetting and then playing back. So in the simulation, you see the ball ricocheting off of a few paddles and pegs then landing finally on the angled ramp.
Let's close the Preview window, and start working on our orange rubber bat. As another soft deformable surface, we'll again need to add the Soft Body Modifier. Let's go ahead and do that. And to make sure it makes it into our simulation, we'll select the Soft Body Collection and then add the bat in. Once you've made the assignment, verify the name Rubber Bat over the right-hand column.
Let's now create another preview. Now we know we're going to have to turn our performance down a little bit, so let's right away change our substeps value to 2. Once we've done that, we'll go ahead and play things back. Okay, now we obviously have a problem here. Let's stop, close our window, and think things over. In troubleshooting a soft-body simulation, one of the first things we ought to consider when getting such a dismally slow preview is just exactly how our two soft body modifiers are being calculated.
Let's start with taking a look at the ball. Over in the Modifier column, as we've previously discussed, Soft Body Modifiers offer two very distinct and very different methods of calculating the way a Soft Body object deforms. The first modifier method is known as Mesh-Based, meaning that the calculation for the object's deformation is derived specifically from the detail in the underline mesh surface--hence the name Mesh-Based. Calculating a simulation based on an object's geometry typically works best when the deforming surface consists of 200 faces or less.
Checking the weight on the ball, we'll see that it indeed falls within that 200-count threshold. To verify that, we'll right-click on the ball and choose Object Properties. Up at the top, in the left-hand side, you'll notice the face count being at 180. Now that rubber foam bat, I'm willing to bet ya, is a different story face count-wise. Let's check it out. We'll select the bat, then again right-click, choosing Object Properties. Yeah, just as I suspected. Look at its face count: 1,120.
So if we are given an opportunity to calculate things differently with a Soft Body Modifier, we might indeed want to at least consider doing so with an object that has as many faces as our bat. Looking directly below the Mesh-Based option, you'll come across the second method of calculation for the Soft Body Modifier, that being something called FFD-Based. Using an FFD-Based configuration means that any object deformation calculations made will be based on or will come from a freeform-deformation-type modifier that's been applied to that object.
And that setup usually allows Max a more efficient way of calculating the deformation for a higher face- count object. So let's do that. With the bat far exceeding the suggested 200 face limit for mesh-based calculations, in the Modify column we'll change the bats calculation to FFD-Based. Once that option has been changed, we can then drop below the Soft Body Modifier in the stack and add in an FFD modifier. When the warning comes up, we can go ahead and say Yes.
In the Modifier List, we'll use the box style of FFD, which will give us a little more freedom in determining the number of control lines in our deforming lattice cage. Once we've applied that FFD, because of the shape of our bat, let's change the lattice layout to 10x3x3. We can do that in the Dimensions category, clicking on the Set Number of Points, and from here we'll simply enter our numbers. We use a Length of 10, and we'll change both the Width and the Height to 3.
Let's now make another preview and see how things turn out. With each and every vertex on both the bat and the ball being animated, as you can see, the preview still lags quite a bit. Now that we've optimized the Soft Body Modifier as best as we can, we can now go back in and consider lowering, once and for all, the substep calculation value. Doing so will cost us a little bit of accuracy at this point, but it will allow us to pick up some speed playback-wise.
In our Preview window, let's see how things would playback using a substeps value of 3. So that's a little better improvement on the way that we're able to see things being played back. The Soft Body Modifier has a few additional controls that we can now tweak in order to change the way our ball and bat deform. We'll take a look at those adjustments in the next video. Before we do that though, let's save our file up as Soft Body Maze02, so we can take it with us.
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