>> As we have already discussed, tasks in particle flow help us add or give intelligent direction to particles that have been birthed into a flow. What we want to do in this chapter is spend some time looking at a few of the more commonly used tests in order to help us become more familiar with both the general way in which test work and also the features and controls found on the specific test operators that we will take a look at. To help us to get started with this, we have in our style scene here an interesting little grinder type contraption that is being setup on our experimentation table with some animation key frames already applied to it.
We also in fact have most of our particle system already in place which if I just pull up particle view using this six key I can enable and then play for you. Now, for the first few frames here we see that our effect plays back reasonably well, but due to the fact that the particles in this flow have been left with their default infinite life span, things start to slow down pretty quickly. The danger here of course is that should the number of frames on the time line be sufficiently high.
In other words, considerably greater than the low count of 100 that we are working with here, then our workstation could be in danger, if you will pardon the irresistible pun of grinding to a halt as particles are added to but never get deleted from an event. The first thing we clearly need to do then is set up some kind of delete operation on the particles. One way of doing that and perhaps the easiest option available would be to place a delete operator inside the event. So, let's drag one of those from the depot and drop it into our event, placing it just below our force operator.
Of course, the problem we will instantly run into is the fact that our particles are now being birthed and deleted pretty much instantaneously. And so, if we scrub the timeline we see that there are no particles showing up in the scene. What we ideally need in this instance is a way of telling the delete operator to only get rid of particles once they have reached a certain age. Hopefully, aged test functionally is in fact built into the delete operator itself. With it selected inside the event, we can see in the parameter area that the third remove option we have available is indeed by particle age which as soon as we enable causes the particle flow system to both assign and track the age of every particle inside the event.
Their lifespan is measured or set by a means of a frame value. So, if we punch in eight here along with a variation setting of five, we are telling particle flow to delete any particle that is at the very least three frames old and at the very most thirteen. If we hit play again we can see that things now run much more smoothly and realistically in terms of the particle effect itself. What we want to do at this point is add a little more visual interest to the effect by creating a secondary set of particles, ones that represent a slightly different set of sparks and that behave in a somewhat altered manner.
To do this we can come back down to our depot, drag out an age test and drop it into the event just above our recently added delete operator. Selecting the test we can add the same values as set in the delete operator, so a test value or a life span of eight frames along with again a variation of five frames. Of course the beauty of being able to add tests into a flow is that we can use them to redirect particles based in this instance on their age and send them off to a new event where we can apply different look and behavior controls to them.
As we already have a second event set up inside particle view, let's grab the output port of our age test and drag it down to the input for our second event. Again, when we get the target cursor we can release the mouse button to connect the two events together. Now, rather than being deleted at the age test value set, particles are being passed from one event to another. Well, this produces if we scrub the timeline a little are a much smaller set of particles whose characteristics with regard to both their look and behavior are being controlled now by the operators in this second event.
So, up to this point we've created our effect using two different age test options. One, found in the delete operator and the other in the age test operator itself. There is, however, one more effect we can look at here that, again, makes use of the fact that our particles now have a trackable age inside of the event. To demonstrate what that is, let's hit the M key on our keyboard to open up 3Ds Max's material editor where, as you can see, we have a material setup with a particle age map plugged into its self-illumination slot.
If I just hit the render button here, after a while, what we will see is that we are now applying a material affect to our particles based again, on their age. In this instance, assigning different colors to the self- illumination of our particles based on a fixed percentage of their age. So, within the lifespan that we have assigned them our particles will start off glowing white. At 15% of their lifespan they will swap over to this slightly orange white and then, once they hit 70%, they will switch to this deep orange which, of course, the particles will keep until being removed from the event by the delete operator.
All in all then, even though we have only taken a very quick look at making use of particle age tests, we can still hopefully see the possibilities that stats open up once our particles have been assigned an age inside an event that can be tracked and used as a catalyst point for age based tests and even material effects.
- Deconstructing a flow
- Making use of events
- Creating a standard flow
- Reusing effects
- Adjusting the Birth, Speed, Shape, and other operators
- Making tests that create events
- Creating rainfall
- Setting up a Splash system