1. Introduction to Houdini Muscles — Transcript

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1. 0:00I'm liset levik and I am a character
2. 0:02effects TD at side
3. 0:04effects in this Houdini 20.5 muscles
4. 0:07Master Class series myself and John
5. 0:10Mariella will be showing you everything
6. 0:11you need to know to simulate muscles in
7. 0:14Houdini John will start out by
8. 0:16introducing the broad Concepts and doing
9. 0:18a basic muscle SASS and then I will do
10. 0:20an in-depth node by node breakdown of
11. 0:22the entire muscle workflow we know that
12. 0:24there are many people who have used
13. 0:26other dcc's and packages for muscles in
14. 0:28the past and are looking for an
15. 0:31alternative for this reason I will try
16. 0:33not to assume too much Houdini knowledge
17. 0:35and explain things that may seem basic
18. 0:37and obvious to a more seasoned Houdini
19. 0:39user but long-term Houdini users fear
20. 0:42not this is a thorough and comprehensive
21. 0:45Master Class not just for
22. 0:47beginners in the second part of the
23. 0:49series we will cover additional Advanced
24. 0:51topics such as Target shapes and rest
25. 0:53muscle D
26. 0:54intersection note that these Advanced
27. 0:56videos will be uploaded as they are
28. 0:58created skin and tissue will be covered
29. 1:01in their own separate master class and
30. 1:04now over to John Mariella for his
31. 1:06overview of the muscle
32. 1:08system so what is the Houdini muscle and
33. 1:10tissue system well it's a set of Houdini
34. 1:12digital assd nodes that interact with
35. 1:14and wrap around Vellum
36. 1:16functionality your surface models are
37. 1:18brought into the system turned into
38. 1:20solids or tetrahedrons we then use an
39. 1:22assortment of special purpose hdas which
40. 1:25for the most part merely add or modify
41. 1:27geometry attributes once the solid
42. 1:29geometry is prepared we feed it into one
43. 1:30of the solver nodes the solver nodes are
44. 1:32wrappers around pre-wired Vellum
45. 1:34constraints and it contained Vellum
46. 1:36solver the attributes passed in with the
47. 1:38solid geometry are used to modify or
48. 1:40enable the constraint properties before
49. 1:42they're fed into the velum solver which
50. 1:44runs your
51. 1:46simulation the overall intent of the
52. 1:48system is to simplify much of the
53. 1:49complexity involved in creating
54. 1:50musculature and fleshy
55. 1:52animations and by abstracting some of
56. 1:54the general terminology and Concepts
57. 1:56inherent in velm workflows into special
58. 1:58purpose hdas hopefully make the system a
59. 2:01little more
60. 2:05intuitive when we work with the muscle
61. 2:07and tissue system we're going to create
62. 2:09three separate simulation passes one for
63. 2:11each of the muscle the tissue and the
64. 2:13skin layers after each simulation pass
65. 2:16your output should be safe to dis
66. 2:17because it's going to be used as the
67. 2:18input for the next simulation
68. 2:20pass your final renderable geometry will
69. 2:23use the last simulation layer as an
70. 2:24input to a
71. 2:27deformer the prerequisite items you're
72. 2:29going to need to get started are your
73. 2:31creature surface model an anatomical
74. 2:33muscle surface
75. 2:35model and anatomical bone surfaces with
76. 2:39animation the surface model should be
77. 2:41constructed in a t pose and a feasible
78. 2:43position near the origin with one of the
79. 2:45principal axes being the plane of
80. 2:47symmetry the outer surface should
81. 2:49completely enclose the muscle and bone
82. 2:53geometry the animation on the bones can
83. 2:55be baked into the geometry but a
84. 2:56deforming mesh with a skeleton or Kine
85. 2:58effects or Channel animation is
86. 3:00perfectly okay
87. 3:05too so let's take a look at how a simple
88. 3:07Vellum Network might differ from our
89. 3:09muscle system in a typical Vellum setup
90. 3:11we would take our geometry wire it into
91. 3:14the Vellum constraint nodes like tedral
92. 3:16stretch constraints or attach
93. 3:17constraints and we would apply the
94. 3:19attachment to specific points on the
95. 3:21muscle and with a quick setup like this
96. 3:23we can launch a simulation with a Vellum
97. 3:26solver if we would then go back upstream
98. 3:28and make any sort of change to the
99. 3:30topology like here I make copies of the
100. 3:33muscles then this might affect the point
101. 3:35selection we made earlier our constraint
102. 3:37has to be reconfigured with a new group
103. 3:39of
104. 3:41points if new Target geometry is
105. 3:43introduced then again there may be some
106. 3:46reconfiguring involved to get the right
107. 3:53result if we want to get individual
108. 3:55muscles to have specific properties like
109. 3:57weaker attachments or a more rig
110. 4:00appearance then we have to make changes
111. 4:02to our Vellum setup maybe add additional
112. 4:04constraints reconfigure them and have
113. 4:07them ready to
114. 4:08simulate what we end up with is a Vellum
115. 4:11Network that is custom made for the
116. 4:12incoming topology and point
117. 4:19count let's compare that to a simplified
118. 4:21muscle system setup here we have a
119. 4:23muscle solidify node a physical
120. 4:25properties node and a constraint
121. 4:26properties
122. 4:27node these hdas will create attributes
123. 4:30on the muscle geometry that tell the
124. 4:31muscle solver how the constraint should
125. 4:33behave muscle ends for example have a
126. 4:36procedurally generated weight mask that
127. 4:38generates attachments to nearby bones
128. 4:40changing the number of muscles or their
129. 4:41point count or the number of bones
130. 4:43doesn't require any special treatment in
131. 4:44the constraint
132. 4:53configuration by giving each muscle a
133. 4:55unique muscle identification attribute
134. 4:57we can select muscles in the viewport as
135. 4:59distinct items
136. 5:00changing physical material properties
137. 5:02and constraint properties is simply done
138. 5:04by adding a new parameter set on the
139. 5:06property node and making tweaks that
140. 5:07apply specifically to whatever is
141. 5:12selected the convenience of this system
142. 5:14makes it easy to set up in tweak
143. 5:16simulations the HDA tools leverage the
144. 5:19idea that point attributes can be added
145. 5:21and varied to tailor the resulting
146. 5:22simulation at an abstracted level one or
147. 5:25two steps removed from the actual Vellum
148. 5:26nodes that do the work the muscle solver
149. 5:29node for instance has preconfigured
150. 5:31constraints to affect muscle ends which
151. 5:34pin the muscle insertions to nearby
152. 5:37bones muscle to muscle attachments which
153. 5:40connect neighboring muscles together
154. 5:41with
155. 5:43springs and muscle to Bone attachments
156. 5:46which connect muscles to nearby bones
157. 5:47with sliding variable
158. 5:49Springs and most of the constraint
159. 5:51properties will respond not only to
160. 5:53stiffness and damping attributes they
161. 5:55can also be controlled by weight masks
162. 5:57to direct where the constraints should
163. 5:58and shouldn't be applied
164. 6:10let's move forward now to an example
165. 6:11where we'll set up a complete muscle and
166. 6:13tissue simulation on an animated
167. 6:14character