Blender. How to cut and key a model for 3d printing — Transcript

Full transcript

1. 0:07in this video i want to show you how to
2. 0:09cut up and key this dog but instead of
3. 0:11using the ball tool add-on as i did in
4. 0:14the previous video i want to use just
5. 0:17the boolean modifiers
6. 0:20okay we'll start with this dog which is
7. 0:22an imported stl
8. 0:24one thing to note before starting this
9. 0:26is you have to apply your rotation and
10. 0:28scale to the object
11. 0:30so you do that by selecting your model
12. 0:34going into object apply
13. 0:37rotation and scale
14. 0:39it doesn't hurt to have your origin
15. 0:40point in the middle of your model either
16. 0:43you can do that by object set origin
17. 0:46origin to geometry
18. 0:52and we add a plane
19. 0:58scale it up
20. 1:02rotate it
21. 1:07and i'll just move it into position
22. 1:14okay that looks okay
23. 1:17now we have to give the plane some
24. 1:18thickness for this to work
25. 1:21so i will add
26. 1:22the solidify modifier
27. 1:25now this is by default 0.01
28. 1:28whatever your units are thick and that
29. 1:30could be a bit too thick for 3d printing
30. 1:32it will take too much out of the model
31. 1:34so i'm going to make this as small as i
32. 1:35can get away with
33. 1:40there we have a very thin
34. 1:43plane now mine is flashing red because i
35. 1:46have my face orientation set to on and
36. 1:48this is so thin that you can see the
37. 1:50inside through the outside but that's
38. 1:52okay
39. 1:55now we apply the solidify modifier
40. 1:59select the model
41. 2:02and we'll add our boolean which is here
42. 2:06we set edit the difference
43. 2:09and select the plane
44. 2:15now we apply the boolean as well
45. 2:22at this point you can turn the plane off
46. 2:24it'll make it easier
47. 2:26you can see here there's a very thin
48. 2:28line in your model but there is still
49. 2:29only one object
50. 2:32so now we have to separate these two
51. 2:34parts so go into
52. 2:38edit mode
53. 2:41and make sure that nothing is selected
54. 2:46alton a will unselect everything now we
55. 2:49need to do is hover your mouse over one
56. 2:51of the parts
57. 2:52let's say here and press l
58. 2:57and that has now selected everything
59. 2:59up into this cut we made
60. 3:02now press p
61. 3:05selection
62. 3:11and then we go back into object mode
63. 3:14we now have two objects and this one you
64. 3:17can grab as you can see
65. 3:22now i'm going to rename these objects
66. 3:25just to make it easier for the rest of
67. 3:26this tutorial
68. 3:30i'll call this one front
69. 3:34and the other one back
70. 3:39not very exciting i know
71. 3:41okay now we want to put in
72. 3:44the
73. 3:45keying object i'll use a cube as it's
74. 3:47most simple
75. 3:49first of all we'll turn off one half of
76. 3:50the model
77. 3:52the front half
78. 3:55now i'll put the
79. 3:563d cursor somewhere in the center of
80. 3:58this with shift and right click
81. 4:02and add a cube
82. 4:07now i'll scale this up
83. 4:09to something that looks sensible
84. 4:12might actually be bit big but it'll do
85. 4:14and then we select the model
86. 4:18add boolean
87. 4:20change this to union
88. 4:24and with this select the cube
89. 4:29apply it
90. 4:34and if i actually turn off the cube now
91. 4:36you'll see that this object now has a
92. 4:38key
93. 4:42let's turn back on the cube because
94. 4:43we'll need it
95. 4:46turn the back of the model off and turn
96. 4:48the front on
97. 4:52this is still the same cube but we don't
98. 4:54want the hole it makes to be exactly the
99. 4:56same size as the key we made in the
100. 4:59other part of the model otherwise it
101. 5:00won't fit
102. 5:01so let's increase the size of this a
103. 5:04little bit the easiest way to do this
104. 5:09is simply by changing these
105. 5:12now i will change it to 9.6
106. 5:16on the x y and z
107. 5:27one thing to bear in mind is if we
108. 5:29increase the x y and z dimension by
109. 5:32point two as i did in this case
110. 5:35that point two is an increase in scale
111. 5:38from the center of the object which is
112. 5:40where your origin is so you really get
113. 5:42point one on this side and point one on
114. 5:44that side
115. 5:45same up here and down there which may
116. 5:48not be enough it may be enough it's
117. 5:50something that you have to experiment
118. 5:52with yourself
119. 5:55okay so we have the cube and we have it
120. 5:57increased in size all we need to do now
121. 6:00is select
122. 6:01the front part of the model
123. 6:04add a boolean
124. 6:08and we keep it on difference
125. 6:10select the cube again
126. 6:15apply it
127. 6:20turn the cube off
128. 6:22and there you have it
129. 6:23if we turn the back of the model back on
130. 6:25there you go
131. 6:27now in theory if we put the x-ray
132. 6:31mode on we should be able to
133. 6:34zoom in and if you look very carefully
134. 6:37at the right angle
135. 6:40you should see
136. 6:42that there is a gap between one part of
137. 6:45the model and the next
138. 6:46so there you go
139. 6:48that's how you do cutting and keying
140. 6:51with booleans it's simple
141. 6:54if you want to do a more organic cut it
142. 6:56works in exactly the same way except
143. 6:59you just need to make your organic
144. 7:02cutting tool
145. 7:04there are plenty of ways of creating a
146. 7:07cutting tool
147. 7:10it's quite common to create a circle and
148. 7:13move it around until it's in the right
149. 7:14place but i'm going to try something
150. 7:16different on this one
151. 7:18i'll move the 3d cursor
152. 7:20to approximately where i want to cut the
153. 7:22leg off
154. 7:26and i'm going to add a single vertex
155. 7:28here the way you make a single vertex
156. 7:32is to
157. 7:32basically add anything in this case i'll
158. 7:35do a cube
159. 7:37add
160. 7:38mesh
161. 7:39cube
162. 7:41go into edit mode and with all the
163. 7:44points selected
164. 7:45press m
165. 7:47merge at center
166. 7:49okay one vertex
167. 7:54now if we go back into object mode
168. 7:57we can add a shrink wrap modifier to
169. 7:59this single vertex
170. 8:01and we'll use the dog as the shrink wrap
171. 8:04target
172. 8:10select the dog here
173. 8:13and this will now snap
174. 8:15to the dog
175. 8:17make a little offset actually it just
176. 8:19makes it a bit easier
177. 8:21okay we should now go into edit mode
178. 8:25that's the last single vertex selected
179. 8:27turn on snapping
180. 8:29to face
181. 8:35and now
182. 8:36with this
183. 8:38single object we can extrude it around
184. 8:40our dog
185. 8:47pretty rough
186. 8:54when we get to the
187. 8:56end
188. 8:58we join the two
189. 9:00points together
190. 9:03with f
191. 9:06i'll just make sure that actually did
192. 9:07happen by turning off
193. 9:09the dog yeah you can see it happened
194. 9:13so let's apply this shrink wrap modifier
195. 9:18and turn off the dog for the moment
196. 9:22that's our starting shape
197. 9:24and just have a look at it in edit mode
198. 9:27looks fine
199. 9:30now turn the dog back on
200. 9:33select all the points
201. 9:35of your cutting tool
202. 9:39extrude
203. 9:41and scale
204. 9:45i've noticed that doing it this way the
205. 9:46normals on the last part are different
206. 9:50from
207. 9:51this part but that's okay
208. 9:53just select them all
209. 9:55go to face mode
210. 9:56a
211. 9:59recalculate outside
212. 10:01they're all the same way around now
213. 10:03that's okay now we need to turn the dog
214. 10:06off for a moment
215. 10:08select the inner loop here
216. 10:15extrude scale
217. 10:18extrude scale
218. 10:21extrude scale
219. 10:24extrude scale
220. 10:28extrude
221. 10:29don't scale
222. 10:31but instead m
223. 10:33merger center
224. 10:36probably a good idea to turn snapping
225. 10:37off here
226. 10:38so we now have
227. 10:40a cutting plane
228. 10:44you can add a subdivision surface
229. 10:47modifier here if you want it to look
230. 10:49smoother
231. 10:54but don't have to
232. 10:56i'll apply that by going into object
233. 10:58mode
234. 11:00press apply
235. 11:01then like in the previous example we
236. 11:03also have to give this some thickness so
237. 11:06a
238. 11:07solidify modifier
239. 11:10make this really small
240. 11:18and we're basically in the same place as
241. 11:19we were before
242. 11:20apply the
243. 11:22solidifier
244. 11:26turn the dog bang on
245. 11:29select the dog
246. 11:31add a boolean
247. 11:36use the pipette to select the
248. 11:40cube
249. 11:45apply the boolean
250. 11:52turn our cutting tool off
251. 11:55select the dog
252. 11:58go into edit mode
253. 12:02make sure you deselect everything
254. 12:05alt a
255. 12:08hover the mouse over the leg in this
256. 12:10case press l
257. 12:14p
258. 12:17selection
259. 12:21we now have two objects as you can see
260. 12:23over here
261. 12:24go to object mode
262. 12:26grab that
263. 12:30and then you can add
264. 12:32a key in exactly the same way as we did
265. 12:34with the other one
266. 12:35i'll just quickly do that
267. 12:51i'll just
268. 12:53actually show you a little technique
269. 12:54here of
270. 12:55turning x-ray mode on
271. 12:57so you can see that you have the cube
272. 13:02where you want it to be
273. 13:04might want it a bit bigger
274. 13:16and rotated in this case i think
275. 13:23that should be okay
276. 13:46there you go
277. 13:56and there you go in x-ray mode you can
278. 13:58see that we have
279. 14:00this is the cube stuck in the leg and
280. 14:02this is the hole
281. 14:04for the dog and there's a very small
282. 14:06gap around
283. 14:11so that's it
284. 14:13simple
285. 14:17[Applause]