Analyzing a graph in the Graph Editor - Maya Tutorial

- [Instructor] In the previous movie we loaded one of the sample graphs from the Bifrost browser and I've got that loaded in my Maya scene here now. And we can actually see the explosion if we play the timeline. And I've got my time slider hidden so I'll just unhide that, UI Elements time slider, and press the play button and that will cause the simulation to start immediately on frame one. And we can see in the active perspective view we're getting a fireball. To stop the simulation you can hit the Escape key. You can see that down here in help line. Pressing the stop button may not actually stop a simulation. Additionally, you'll need to wait for Bifrost to finish working on the current frame. And if your simulation is taking a long time per frame that means you may need to wait a long time for Maya to become responsive once again. And there's really nothing we can really do about that currently. Bifrost is just built that way. So when you hit that Escape key you may need to wait for a while to get your Maya interactivity back once again. Let's analyze this graph and just see its major components. We can go back to the Bifrost graph from the Windows menu, Windows, Bifrost Graph Editor. But if we don't have any graph selected in the scene then we strangely get this screen once again. So this is another bit of a bugaboo with the current version of Bifrost. If you press the plus sign over here then it will show you a list of all of the graphs that are currently in the scene. And so I can choose the one that's in the scene now which is Standard Explosion and that loads up the graph. There is another way to do this. If we close the graph window again and open up the outliner if we select the graph node in the outliner before launching the Bifrost graph window then this graph will load automatically. So that's really the preferred workflow. Select your graph in the outliner then go to the Windows menu and choose Bifrost Graph Editor and it will load the graph automatically. So let's take a look at what we've got here. I'll maximize this window. We'll see that we've got a create node here. Bifrost is creating a sphere and that's actually a polygon object generated directly by Bifrost. And so there is no input node here. We're not grabbing any geometry in Maya. And we see there's a vary temperature compound and that is, as the name implies, varying the temperature which is going to cause the explosion to have a varied look to it. It won't be perfectly uniform. Then that's being piped into a source air compound. And again, if we select one of these compounds over on the right side we'll see in the info panel some helpful information that tells us what that node does. In this case these are really the source parameters for the air or the atmosphere in which this combustion effect is taking place and it has very important properties such as the voxel resolution or the size of individual elements in the simulation. Moving on I can navigate with the middle mouse button. We'll see there's also a source fuel compound or node and that is determining the properties for the combustion fuel. And that is feeding into the simulate aero node and that is where the simulation actually takes place. And it's the most important node in here. It's taking inputs from the air and fuel into the sources section. It's also taking inputs from the solver settings which determine the exact properties of the simulation, how it's going to behave. And the simulate aero node is also taking an input from this collider node. And currently there are no colliders in the scene but when you create an aero simulation you get a collider node or compound just by default so that you can wire that up. The output of the simulation is going in to an assigned material compound whose job is to, as the name implies, assign a material. And there's the material in the Maya hypershade. And this explosion material node is referencing the hypershade node. So this is actually an input from Maya and it's being assigned with this assign material node. And then finally the assigned material node is going to the output which results in the fireball we see in the view ports. That's a quick analysis of one of the example Bifrost browser graphs showing the dataflow for an aero combustion effect which is the standard explosion.