Distortion shockwave effect (like Expedition 33) in Unreal Engine Niagara — Transcript

Full transcript

1. 0:00Hi everyone. These tutorials are meant
2. 0:02to be short and sweet, focused on a
3. 0:04single thing. Today, we're making a
4. 0:06refractive shock wave similar to some of
5. 0:08the ones you can find in Expedition 33.
6. 0:10Here's a quick example of what we're
7. 0:12trying to achieve, a shock wave that
8. 0:14distorts what you see through it.
9. 0:16Expedition 33 uses these extensively,
10. 0:19and I was curious to see if I could make
11. 0:20them by myself. The physical principle
12. 0:23that makes a shock wave visible in real
13. 0:25life is that air gets compressed so much
14. 0:27that its index of refraction becomes
15. 0:29different from the air surrounding it.
16. 0:31In that sense, it becomes similar to
17. 0:33looking through glass or water. Our
18. 0:35approach is going to be very basic just
19. 0:37so you understand how it works. You can
20. 0:39then extend the technique to achieve
21. 0:41more complex effects.
22. 0:44First, we'll create a material that is
23. 0:45just a ring with its radius controlled
24. 0:47by a dynamic material parameter. That's
25. 0:50pretty easy. The first step is to get
26. 0:52the distance of the texture coordinate
27. 0:54from the center. This gives us a
28. 0:56gradient with zero in the middle and one
29. 0:58at the edges. Then we use the sphere
30. 1:01mask node to convert it into a ring.
31. 1:03Here we use the dynamic parameter node
32. 1:06so we can control the radius and
33. 1:08thickness from outside the material,
34. 1:10specifically from our particle system.
35. 1:13We'll set some defaults just so we can
36. 1:14visualize it in the material editor. If
37. 1:18we plug this into the color, we see that
38. 1:20we get a ring. Now, let's change our
39. 1:22material settings so we can use the
40. 1:24refraction pin. We change blend mode to
41. 1:27translucent, lighting mode to surface
42. 1:30translucency volume, and finally
43. 1:32refraction method to index of
44. 1:34refraction. Now that we have access to
45. 1:37our refraction pin, we want the material
46. 1:39to have the same refraction value as the
47. 1:41air where the material is black, the
48. 1:43value is zero, and a higher refraction
49. 1:45index where it is red. the value of one.
50. 1:48So we add a remap value range node and
51. 1:50map zero to one and one to 1.54 which is
52. 1:54the refraction index of glass. Of course
53. 1:57we remember to set the opacity to zero.
54. 2:00As you can see in the preview, we get a
55. 2:02ring that sort of distorts whatever is
56. 2:04behind it. Now let's use this in a
57. 2:07Niagara system. We'll create an empty
58. 2:09system and add a single looping particle
59. 2:12emitter. This will spawn a single
60. 2:14sprite. Let's change its scale to 50 to
61. 2:17make it more visible. In sprite
62. 2:19renderer, we'll use the material we just
63. 2:21made and make sure it is velocity
64. 2:23aligned. Finally, we need to add a
65. 2:26dynamic material parameters module in
66. 2:28the particle update stage. Here, we want
67. 2:31to update the radius over time. So,
68. 2:33we'll add a float from curve and make it
69. 2:35go from 0 to 0.25 over the lifetime of
70. 2:39the particle. Let's set the thickness to
71. 2:410.05.
72. 2:43And there you have it. It's subtle, but
73. 2:45you get an expanding ring that distorts
74. 2:47whatever is behind it. You can play with
75. 2:49the values in the material to make it
76. 2:51more or less sharp, have a higher index
77. 2:53of refraction, add some noise, etc. One
78. 2:56other thing that could be interesting is
79. 2:58to use a mesh renderer with a sphere
80. 3:00made of a material with a different
81. 3:02index of refraction than air, and have
82. 3:04its scale, expand with time. That's it
83. 3:07for today. I hope you learned something
84. 3:09without wasting time having to skip
85. 3:11through 10 minutes of intro and
86. 3:13unrelated stuff. Leave a comment if you
87. 3:15have any questions or to show me what
88. 3:17you have made with this technique. And
89. 3:19of course, like and subscribe. Till next
90. 3:21time.