Engine 4 tools and technology.

I'm Zak Parrish and I'm joined today by Epic Games senior visual FX artist Tim Elek.

Hi Tim.

Hi Zak.

Now, you worked on several of the environmental and weapon effects in Epic's Infiltrator tech

demo is that correct?

Yes.

Can you talk to us about some of the effects that you worked on?

I created primarily environment effects and weapon effects, muzzle flashes, impacts, tracers.

And then the environment effects would typically include water, smoke, any kind of haze or

atmosphere.

We're going to be splitting this up into two separate parts. We're going to do one part

with some of the effects that you worked on and then we'll save some for another video.

So what are we going to take a look at in this first video?

In this first video, we're going to look at muzzle flash.

First I'm going to open the effect in Unreal Cascade. And here you can see there are quite

a few components to this effect.

And I really only want to pay attention to this one element here, which is this large

conical shape coming out of the end of the muzzle.

I think this is one of the most important elements to this effect because it really

helps show the power and the size of the projectile that's probably coming out of the end of this

weapon.

And then another element that we have which is new to Unreal Engine 4 is the ability to

emit light into the world using our particle lights. These particle lights are controlled

using traditional Cascade modules.

Light properties are all based off of the initial size and color of the actual particle.

Very nice. Are there any other elements to this muzzle flair that really start to make

it pop, that really bring it to life?

Sure. Another thing that I really think is important to this effect is the distortion

that we're using in the world. This is using the refraction in our material, which is a

new feature in Unreal Engine 4.

We had distortion in Unreal Engine 3 but we have refraction in Unreal Engine 4 now.

I really feel like this helps connect the effect to the world and just sort of pushes

the pixels around and gives you a sense that it's part of the environment.

If I re-enable all of the different elements, you can see the muzzle flash has some venting

coming out of the sides. There are several different components that really help show

you that this is also an automatic weapon.

Yes, that just looks like it should be loud and powerful and able to stop a raging elephant.

I also notice that it looks like we have some shell casings flying out of the side of the gun.

Yes, the shell casings are being emitted through the effect which is great because now I can

control those all in one location.

So, you're saying that the muzzle flash and the shell casings coming out are all part

of the exact same effect?

Yes, the shell casings are in local space so they inherit the transforms of the weapon.

And then I just offset their positions so that they eject from the right location on

the side of the gun.

If I fly up over here, you can see our giant robot. And he's just pouring shells out into

the environment.

He burned through the ammo.

Using a CPU system, I can track the position of these shells, and then emit smoke from

each shell as it's falling through the world.

I see this guy also has tracer fire as well.

Yes.

Now is that part of his muzzle flash effect or is that separate?

The tracer is bundled with the muzzle flash. It helps us show the direction without having

to add another component and track two items in Matinee. You can just fire off one effect.

Ok, so these are some of the impact effects that we're seeing at the very tail-end of

Infiltrator when the flying robot is shooting at the ground?

Yes. And typically when we're creating an impact effect, there are a couple of things

we keep in mind. We think about the size of the projectile and also think about the surface

that the projectile is impacting.

So here we have concrete. The first thing I did was create some meshes that came from

this concrete on the ground.

They have the same materials so they'll have the same visual qualities. And I'll emit that

concrete with Cascade.

Because the concrete has a lit material on it, it's accepting the lighting from the world

as well as the lighting coming from the particle system.

I notice you're also kicking up a lot of, I guess it would be more dust than it is smoke

as the concrete gets pulverized. Is that actually being lit in the world?

Yes, all of the dust is being lit by the lights in the world. You can see here that I added

a purple light to the side of this effect so that you can get the effect of the lighting

on the smoke and the dust.

You know it's funny, you had to move the camera over before I noticed, but there's also a

lot of gravel being kicked up.

Yes, all of these little tiny chunks are translucent particles using a translucent material. So

they'll get illuminated and lit just like the meshes do.

And they'll actually collide and bounce along the ground based on the surface normal and

the depth buffer.

So, those are just little sprites? They aren't really tiny meshes?

Yes, they're just all small sprites along with the sparks. And they're all using our

GPU particle system as well as the new depth buffer collision.

In the vista shots of Infiltrator, you'll notice there's a lot of traffic and robots

moving around.

In this case, I'm just emitting the robot mesh that the modelers created. And I'm attaching

lens flares and particle lights to the robot so that as they move through the world, they're

actually illuminating all of the geometry.

And you can see more of them here in the background. We used those extensively in the vista shots.

They just add an extra detail to the world.

That is too cool.

Well, thank you very much for your time and thank you all for joining us. And we will

see you all on the next Inside Unreal.