Delete Instances (Destroy(), Remove(), Debris) - Roblox Advanced Scripting #2 — Transcript

Full transcript

1. 0:00hey thanks for stopping by in this episode of  my Roblox Advanced scripting tutorial series I'm
2. 0:04going to be discussing about delete instances what  they are how they are used and why you should use
3. 0:11them delete instances is a term that I kind of  made up because it reflects on ways that Roblox
4. 0:16has provided us tools to handle unnecessary or  unneeded objects or instances that we just have
5. 0:22lying around inside of our Roblox games that we  create and in this guide I'm going to show you
6. 0:28different ways of how Roblox has provided us these  tools to help us with with those situations but in
7. 0:34order to understand what I'm talking about  let me show you an example all right let's
8. 0:38think about this for a minute so I just quickly  created something that I think will be a great
9. 0:43example for what I'm about to show you in this  episode so right in front of me I have a coin
10. 0:49spawning pad that randomly spawns coins onto this  pad and then after a certain period of time which
11. 0:55is about 5 Seconds they end up disappearing uh  the reason I have it the reason I hav't do this
12. 1:00is because my initial intention was that when a  player steps on one of these coins then they will
13. 1:07add a point to their bleeder stat but I did not  create that yet um and so what's really important
14. 1:13to note here is that these coins when they're  not being picked up they despawn on their own
15. 1:19after 5 Seconds it doesn't have to rely on me to  pick them up before they actually despawn because
16. 1:24if I just come over here and pick up one of these  coins they uh disappear uh like in intended uh we
17. 1:31don't have to deal with them anymore once they're  collected we just wait for the next one to spawn
18. 1:34in and so Roblox has provided us three methods to  deal with with deleting instances and I'm going
19. 1:40to be showing you how to do all three of them  in this episode all right like I mentioned with
20. 1:44my example we don't want to keep these parts  lying around inside of the game that we don't
21. 1:48need anymore otherwise it'll slow down Roblox  and we have to have a healthy amount of garbage
22. 1:55collection when it comes to handling what parts  we don't need and and what parts we should keep
23. 2:01in the world so there's something I want you to  understand in our Explorer we have all of these
24. 2:07instances and parts they all have a parent that  is basically like the folder that the object or
25. 2:15part or whatever it is is contained inside so if  we look at our base plate our base Plate's parent
26. 2:23our parent property here is workspace which is  basically the folder of base plate base plate
27. 2:29is a child also known as like a file inside of a  folder inside of workspace that also applies to
28. 2:36everything else that's here inside the workspace  you have the camera terrain spawn location and
29. 2:41let's say I were to insert a new part so if  I go to model up here and then click on part
30. 2:46I inserted a new part into the workspace but if I  go over here to the right and click on part in in
31. 2:53the Explorer we can see that the parent is also  inside of the workspace and so that's something
32. 2:58I want you to keep aware of when I'm going to be  discussing about remove and how this affects parts
33. 3:03inside of the game so now that we have this part  how do we want to remove it through script well
34. 3:08the first thing we're going to do is obviously  create a script and uh on the right side let's
35. 3:13create a script that'll be parented to part so  we will click the plus sign that's in part and
36. 3:19then we will say script so now as we can see here  with the script the parent property of the script
37. 3:24is the part itself so we want to be able to locate  that part and uh we're going to do this by first
38. 3:30deleting this and then we'll make reference to  that part by saying local part equals script.
39. 3:37parent so we've made reference to the part that's  basically located on the script's parent and I'll
40. 3:44simply show you the first method but before we  do that let's actually create a weight uh at the
41. 3:48very beginning of the script so that we can see  the change happening when we delete it so we're
42. 3:53going to say task. weight and then inside of  these parentheses we're going to put put a
43. 3:59number indicating the number of seconds we're  going to wait until we execute this script so
44. 4:04we'll say six and then down here let's say part  colon remove and then we will wrap these around
45. 4:12in open and close parentheses so let's go into  the game let's hit test and hit play so that we
46. 4:18can actually see the change that happens and so  let me open the Explorer really quick so we can
47. 4:23really see the change so after about 6 seconds as  you can see the part disappeared not only in the
48. 4:28workspace but also in the Explorer so that prettyy  much did what we intended it to do so what's the
49. 4:34issue here there's a lot of intricate stuff that  goes on in the back of roblox's servers and game
50. 4:41management stuff like that that it's kind of a  bit complicated but effectively what this did
51. 4:47was that it took the parts parent over here if  I go into the Explorer click on parts and then
52. 4:53see its parent this effectively set the parent  of the part to nil and as you know know nil is
53. 5:01a nonone value it's a value that does not exist  so now that we know that remove basically sets
54. 5:08the parent of the of the part to null it's sort of  just floating around in the game's content but now
55. 5:17the game doesn't know what to do with it because  there is no parent set to it so it didn't fully
56. 5:22get rid of it so Roblox has provided a better  alternative called destroy so if we go into our
57. 5:28script and replace remove with destroy instead we  can actually see that it does multiple things it
58. 5:36not only sets the parent property to nail like  remove does but it also locks the parent of the
59. 5:42instance and it disconnects all connections and  calls destroy on all children so it basically
60. 5:49does what remove does but as an added layer of  security it does all these other things in order
61. 5:55to provide as much performance as the game can  give you uh when you get rid of a part so all
62. 6:03in all this is just a much better method to use  uh over remove so I mentioned in my example in
63. 6:08the beginning of this tutorial that I basically  had coins that came into the game and then after
64. 6:14a certain period of time I made them disappear  that was actually that actually didn't have to
65. 6:19do with putting in a weight statement before  destroying it there's actually a much better
66. 6:24way of dealing with that sort of stuff to know um  after a certain amount of time to to just delete
67. 6:31the instance whenever I need it to without using  a weight statement and I'll show you two ways of
68. 6:36doing this and why I recommend this third method  rather than using a weight statement so this third
69. 6:41method is called debris and this is basically a  model that Roblox has provided where it handles
70. 6:49garbage collection when you want to delete a part  within a certain within a specific amount of time
71. 6:56rather than having to delete the part through  one single command so if we go back up here to
72. 7:02our script we can see that we have our weight  statement here in the very first line before
73. 7:07actually destroying the part I actually would not  advise doing this by using a weight statement and
74. 7:12then destroying the part I will explain to you why  in just a little bit so let's delete this first
75. 7:19line up here with the weight statement and let's  also just comment out this part really quick by
76. 7:24putting in the two dashes in front of the command  so let's hit enter down here and and let's type in
77. 7:31game. debris because this is uh the framework that  we're going to be using in order to handle garbage
78. 7:38collection and we're going to say colon add item  in the first argument we're going to throw in the
79. 7:46part and then we're going to separate using a  comma for a second argument and we're going to
80. 7:52give a number so we used the number six for the  the time we wanted to use for uh when the part was
81. 7:59actually are going to be destroyed so this is how  we're going to do it instead of using task. wait 6
82. 8:04seconds and then destroying the parts we're simply  doing this in one line by saying game. debris and
83. 8:10then this is the method we're using add item we  want to add this part to the the debris garbage
84. 8:17collection um after 6 seconds that this line has  been executed so if we go back into the game and
85. 8:26then hit play We Should pretty much see the same  exact result just in a different just using a
86. 8:33different framework so in about 6 seconds the part  should be removed if we look at Explorer then the
87. 8:39part is definitely not there in the Explorer  anymore so that effectively did the exact same
88. 8:44thing as destroy but we gave it a certain but we  gave it a certain time before it actually deleted
89. 8:50itself now it's time to answer the question why  should we use debris over using a weight statement
90. 8:56and then destroying the part okay so going back  to my coins example Le uh here's the script right
91. 9:01here the only thing you really need to know  about is the um delete instance part where I
92. 9:07basically have a weight statement here that Waits  5 seconds and then it destroys the part let's this
93. 9:13is not a good idea let's see what happens when we  actually do decide to have a weight statement and
94. 9:18then destroy it when you saw my original example  every single second there was a new coin that was
95. 9:24spawning in and then it was going to delete itself  after 5 Seconds it wasn't dependent on any other
96. 9:30coin that was inside of the spawn location before  it deleted itself but now it seems like when I
97. 9:35added a weight statement it seems to wait for  the coin to disappear first before spawning in
98. 9:41another one this is clearly not what we want and  the reason I can explain why this is happening is
99. 9:47because effectively when we spawn in a coin using  calling this function here um in our while true do
100. 9:55statement it creates a new coin it sets that new  coins parent to workspace uh and then it's going
101. 10:04to wait 5 seconds before destroying this new coin  but what you don't realize is happening is that
102. 10:11this function is being called and we've added  in a weit statement here where we're literally
103. 10:17telling the script to stop what it's doing for  5 seconds and then destroy the new coin before
104. 10:23ending the function and then jumping back down  to here to start the script all over again the
105. 10:29reason this is ineffective is because we're  actually telling the script to wait 6 seconds
106. 10:35instead of one before spawning in another coin  so 5 Seconds here for it to be destroyed and
107. 10:42then another second here in order to spawn the  coin again when in actuality we want we want
108. 10:48the loop to go every second rather than every 6  seconds and so when we use debris it's actually
109. 10:55not dependent on the previous coin before it  it spawns in the next one so if I go back to
110. 11:01the script and quickly comment these two points  out and then uncomment the new one game. debris
111. 11:08add item new coin 5 Seconds we will see that  it's not dependent on the previous coin before
112. 11:14spawning in the next one so instead of waiting 6  seconds so waiting 5 seconds for the first one to
113. 11:20despawn and then wait another second to spawn in  the next one it just simply Waits 1 second before
114. 11:27spawning in the next one and then independently  each coin will despawn after 5 Seconds that's
115. 11:33why I think using ad item for game. debris is a  better method of when you want to get rid of an
116. 11:40item after a specific number of time so in summary  remove basically just sets the parent of whatever
117. 11:46instance you're trying to get rid of to nil and  I'm just going to say do not use move it is not
118. 11:53a very effective strategy to get rid of stuff  but it it's still great to understand how this
119. 11:58stuff works Works destroy gets rid of whatever  instance you're trying to get rid of in the most
120. 12:05optimal way possible and you should only use this  if you want to immediately get rid of an object
121. 12:13without having to wait for it and then debris  should be used when you want to get rid of an
122. 12:19instance after a set amount of time that you give  it it's important to know when to use debris and
123. 12:26when to use destroy I hope you found this episode  to be helpful uh be sure to check out my other
124. 12:31videos on my Advanced scripting tutorial series  and I will see you in the next one take care