WEBVTT 00:00.360 --> 00:03.140 Welcome to copying physics properties. 00:03.150 --> 00:06.500 So where is the physics data actually stored. 00:06.600 --> 00:08.030 Well see in a few moments. 00:08.040 --> 00:11.580 Physics properties are not linked to the objects or data. 00:11.580 --> 00:12.980 Data block. 00:12.990 --> 00:17.460 As you might think they are like the materials are when you set those up. 00:17.460 --> 00:23.430 Now they are part of the scene data block and this means that unfortunately when you append an object 00:23.460 --> 00:25.450 that you've set physics up. 00:25.650 --> 00:30.780 Well the actual data itself is not going to come across for the physics set up you'd actually have to 00:31.080 --> 00:37.980 import or sorry in append the scene itself into a new blender far because that's where all the properties 00:37.980 --> 00:39.080 are stored. 00:39.090 --> 00:42.300 Now you cannot make links to the physics either. 00:42.300 --> 00:48.180 So when you used to use and control an L to steal the material data from another area there's no option 00:48.180 --> 00:48.870 for physics. 00:48.870 --> 00:53.460 Perhaps that will change in the future that will be very useful but it's not possible at the moment 00:53.790 --> 00:57.090 simply because we're stored in the scene data block. 00:57.090 --> 01:02.160 Again it's not stored as part of it objects or the object data day to block. 01:02.160 --> 01:09.000 You can however still copy from an active mesh object and will it go explore that now and hop on over 01:09.420 --> 01:10.450 into a blender. 01:11.540 --> 01:17.270 Okay so were over in blender here we have aged the standard cubes we would do normally that sets some 01:17.270 --> 01:18.500 physics up on it's us. 01:18.500 --> 01:20.180 Go ahead and just add it. 01:20.230 --> 01:24.920 A rigid body like we've done before and let's go ahead and play that. 01:24.950 --> 01:32.720 So one of the ways that you can get data from one object to another is of course copying or duplicating 01:32.720 --> 01:34.310 the object itself. 01:34.310 --> 01:40.460 So let's go ahead and stop that from playing that's go back to frayne's ZERO again and using shift and 01:40.460 --> 01:46.670 D we can duplicate our cube and both of them now have physics properties apply to them because it's 01:46.670 --> 01:49.190 derived from the original. 01:49.230 --> 01:55.400 Now if we change it with let's say we go in use all the and make a linked duplicate and just to remind 01:55.400 --> 01:57.530 you that means that they are linked. 01:57.530 --> 02:02.690 If we scale them in edit mode they will scale on both of them scale because they are actually the same 02:02.690 --> 02:03.560 mesh data. 02:03.720 --> 02:04.430 Now. 02:04.510 --> 02:10.700 They will all have the same ply But of course if we set this one having a mass of 5 If we go to this 02:10.700 --> 02:15.260 one it will have a mass of one and this one will have a mass of 1 as well. 02:15.260 --> 02:19.720 And of course that in itself you would think would be a little bit problematic. 02:19.720 --> 02:22.060 It is if you don't know how to handle it. 02:22.100 --> 02:26.300 So first of all before we go any further Where is all of this data stored. 02:26.300 --> 02:29.150 Well it's actually in the scene itself. 02:29.150 --> 02:34.370 And if we scroll down so in the Properties window there is the scene tab it looks like a ball in the 02:34.370 --> 02:35.410 cylinder and a. 02:35.600 --> 02:37.840 I suppose it's a lamp next to it as well. 02:37.830 --> 02:41.330 I can't quite make all of that out but we've got a series of options. 02:41.330 --> 02:47.840 We've got gravity in here now that does affect our scene so if we changed to where the gravity was coming 02:47.840 --> 02:52.760 from at the moment it's set to nine point eight one which is meters per second in this case. 02:52.940 --> 02:57.120 And if we end up just playing it by default. 02:57.350 --> 02:57.940 There we go. 02:57.980 --> 02:59.290 The others just disappeared. 02:59.570 --> 03:05.150 So that basically means that after one second these queues will be travelling as they've accelerated 03:05.150 --> 03:07.670 at nine point eight 1 meters per second. 03:07.700 --> 03:12.650 They'll be travelling at nine point eight one meets per second so after a second if you want to know 03:12.650 --> 03:18.530 the full equation you can go hop over onto Wikipedia but they will have travelled around 5 meters or 03:18.530 --> 03:25.400 so after a second or in this case blender units B because one blend the unit and one meter are pretty 03:25.400 --> 03:28.980 interchangeable when it comes to the default scene that we have. 03:30.280 --> 03:31.650 Now these are falling away. 03:31.650 --> 03:32.530 That's absolutely fine. 03:32.530 --> 03:39.390 If I Antec rigid body world well the physics just stops working because that's where this data is stored. 03:39.400 --> 03:43.620 Now we've got some other options down here the useful ones down here. 03:43.690 --> 03:48.640 And these are some of the trip ups that you'll come across the gotcha's. 03:48.640 --> 03:54.820 We can change the steps per second we can change the solver iteration the higher these numbers the slower 03:54.820 --> 03:58.640 your calculations are going to be but the more accurate they should become. 03:58.810 --> 04:04.330 Don't go too high though other ways you can also give some very undesirable results where things just 04:04.330 --> 04:07.300 go flying off into the aether to stop these things falling. 04:07.510 --> 04:07.860 Okay. 04:07.900 --> 04:12.480 The one that usually gets people is this rigid body cache. 04:12.520 --> 04:17.480 Now if we open that up we can see it starts at 1:00 and goes to 250. 04:17.500 --> 04:22.420 And it says we got 50 frames in memory and it's taking up 12 killer bytes. 04:22.540 --> 04:23.140 That's fine. 04:23.140 --> 04:28.480 That makes sense if we change any of the settings to do with the physics that's go over here and make 04:28.480 --> 04:31.360 the maths two and go back here. 04:31.450 --> 04:33.490 We should see that it says outdated. 04:33.490 --> 04:34.310 No it doesn't. 04:34.310 --> 04:39.000 Let's just change something else the friction and go back here. 04:39.010 --> 04:41.410 Perhaps it needs to be running to be outdated. 04:42.250 --> 04:42.670 There we go. 04:42.670 --> 04:44.810 Cash is out. 04:44.810 --> 04:47.920 And if I pull this open he says outdated. 04:47.920 --> 04:48.540 There we go. 04:48.550 --> 04:50.060 So the cash is outdated now. 04:50.170 --> 04:53.840 The important thing here is the start frame and the end frame. 04:54.040 --> 05:00.670 Now if you were doing quite a long simulation at the moment it would literally stop after 250 frames. 05:00.670 --> 05:09.300 It doesn't matter if you've changed the setting down on the time line to be 300 400 500 It doesn't matter 05:09.310 --> 05:10.480 2000. 05:10.480 --> 05:16.140 It will still stop the simulation after 250 frames and that is something that will catch you out. 05:16.210 --> 05:21.590 If you all do less doing a Domino's scene for instance where one block is hitting another and there 05:21.590 --> 05:28.490 cascading down well after 250 frames or 10 just over 10 seconds at 24 frames per second. 05:28.510 --> 05:34.000 Its just going to stop and if you wonder why go and check out this setting here the rigid body cache 05:34.000 --> 05:36.360 is literally storing the information. 05:36.370 --> 05:41.830 Now what we don't see with these simple cubes falling Let's go back over here is it's kind of locked 05:41.900 --> 05:43.720 24 frames per second. 05:43.930 --> 05:50.230 If it was a more complicated simulation we would see it drop down perhaps even less to one frame per 05:50.230 --> 05:50.860 second. 05:50.860 --> 05:56.940 But once it's run that it's actually stored those 50 frames in this case into cash. 05:57.040 --> 06:00.550 So it doesn't have to recalculate the movements every time. 06:00.640 --> 06:06.810 However everything that you change will actually make the whole cache out of date. 06:06.940 --> 06:12.260 And that's that's the case sometimes you'll do something whilst the animation is running and things 06:12.260 --> 06:16.050 just explode or fly over the place and you just wonder what's going on. 06:16.180 --> 06:21.850 Well if that does happen just reset the simulation or let it loop round any way especially if it's a 06:21.850 --> 06:23.960 short simulation like 50 frames. 06:24.160 --> 06:31.360 So now we've got all of these cubes all set up what we can do is copy the physics from one to another. 06:31.540 --> 06:37.280 Now this is available in the tool shelf under the physics pane and every year. 06:37.300 --> 06:39.110 That's the fifth one down here. 06:39.250 --> 06:41.290 Now we've got a button that says copy from active. 06:41.290 --> 06:46.350 So the easiest way of doing this is well there are a couple of ways of doing it. 06:46.360 --> 06:51.940 But the easiest I've often found is to move all of your objects that you're working with to a separate 06:51.940 --> 06:52.390 layer. 06:52.390 --> 06:58.900 That's one way or in the outline a D select the selection for things you don't want or that you're not 06:58.900 --> 07:01.920 working with at the moment so we've got these three cubes. 07:01.960 --> 07:07.570 Now if I select everything with the aiki is only those three being selected and I can also move them 07:07.570 --> 07:15.160 to another layer like layer 2 and then when I'm looking at that I can simply just hit a and select everything 07:15.160 --> 07:16.960 that's on that layer. 07:16.960 --> 07:23.290 Now I select the one hour and want to copy the information from first it will go that light orange colour 07:23.560 --> 07:24.640 on the origin. 07:24.760 --> 07:26.260 Now because they got physics applied. 07:26.260 --> 07:30.650 Unfortunately we can't look at the actual outline because that's just gone green. 07:30.730 --> 07:32.940 Now let's have a look and see the settings. 07:32.950 --> 07:40.330 Let's give it a friction of one a bounciness of point five and a mass of 10 which we definitely can't 07:40.330 --> 07:44.480 see and let's change it from convects hole to mesh just for this instance. 07:44.590 --> 07:51.610 Now now we've got all that set up we can hit the A key twice and you see that the other origins for 07:51.610 --> 07:59.530 these particular cubes are a dark orange in now if we hit copy from active it's copied the physics data 07:59.770 --> 08:05.260 from this cube to the other two and if we can go and click on them we can see that that is in fact the 08:05.260 --> 08:05.600 case. 08:05.600 --> 08:08.800 They're now all contain the same physical properties. 08:08.800 --> 08:14.530 Now this can be a great way of let's say setting up a scene with multiple lights and you just all set 08:14.530 --> 08:17.590 them up with the same physical properties and then go in to tweak them. 08:17.590 --> 08:24.400 Or indeed if you've got lots of duplicate objects that are actually the same that do need the same physical 08:24.400 --> 08:27.580 properties you can apply across the board. 08:27.580 --> 08:31.500 So now just to practice this I've got a small challenge for you. 08:31.960 --> 08:35.370 I'd like you to go ahead and copy some properties. 08:35.470 --> 08:42.250 So go ahead and set up a scene with five falling primitives and a slightly sloped ground plane so it's 08:42.250 --> 08:48.190 a bit more interesting when they hit it make all of these mesh objects saying that they share the same 08:48.250 --> 08:49.610 physical data. 08:49.750 --> 08:53.510 So they're all going away the same have the same bounciness et cetera. 08:53.800 --> 08:56.950 Now remember to make the ground plain passive. 08:57.010 --> 09:01.840 Otherwise it's going to disappear with all the others and nothing will hit one another which wouldn't 09:01.840 --> 09:02.990 be that exciting. 09:03.010 --> 09:03.670 So go ahead. 09:03.680 --> 09:06.200 Pause video now and give that a go. 09:08.430 --> 09:09.960 Okay guys welcome back. 09:09.960 --> 09:13.670 Let's get set up a scene and hop on over into a blender. 09:14.040 --> 09:15.150 Okay welcome back sir. 09:15.150 --> 09:17.730 We have three cubes here. 09:17.730 --> 09:19.440 I'm going to get rid of two of them. 09:20.300 --> 09:20.960 That's fine. 09:20.990 --> 09:21.400 Okay. 09:21.410 --> 09:27.440 I'm going to add in a plane and just scale that up massively So we've got something there and I'm going 09:27.440 --> 09:34.250 to save my file as well and call it 5 falling objects. 09:34.370 --> 09:40.370 I cannot see my microphone so hopefully that's I can't see through my microphone five falling objects 09:40.450 --> 09:42.110 just got capital in the wrong place. 09:42.110 --> 09:44.730 Anyway enough of my keyboard wizardry. 09:44.750 --> 09:51.740 Let's just play Well let's set all let's add are other objects him first so what else can we have. 09:51.740 --> 09:52.970 Let's have a cone. 09:53.210 --> 10:00.520 And for excitement's Let's actually have the cone rotated X by one eighty six pointing down. 10:00.530 --> 10:02.730 Who knows which way it will actually fall. 10:02.960 --> 10:03.430 Let's hear. 10:03.440 --> 10:09.430 Add in a nother meche let's add in Suzanne the monkey she's always useful to have in a scene keeping 10:09.450 --> 10:11.630 an eye on us and our antics. 10:11.630 --> 10:17.150 There we go there's Suzanne a schifter over here so she's not getting a cone falling right on top of 10:17.150 --> 10:17.600 her. 10:17.630 --> 10:20.540 And then of course that's three so let's go in. 10:20.540 --> 10:24.110 Now I've got three extra things added in so let's see. 10:24.110 --> 10:31.460 That's all teapots are that's going to come in pretty large that's shrink it down just a little and 10:31.460 --> 10:32.570 move over here. 10:32.570 --> 10:33.500 And what else have we got. 10:33.500 --> 10:34.450 We got one more object. 10:34.450 --> 10:35.460 What shall we have. 10:35.540 --> 10:36.770 Choices choices choices. 10:36.770 --> 10:42.410 Let's go for a cylinder and let's tilt it on its side. 10:42.410 --> 10:45.380 So I'm going to rotate it round the y axis by 90. 10:45.380 --> 10:45.950 There we go. 10:45.950 --> 10:48.410 So that's a great starting point. 10:48.500 --> 10:49.610 And now I'm going to. 10:49.610 --> 10:54.800 This one's already got physics properties enabled so I'm going to select everything from that go over 10:54.800 --> 11:01.730 to the physics tab and copy from active and then remembering to set this to passive. 11:01.790 --> 11:04.190 In fact I can just hear and passive over here. 11:04.190 --> 11:09.370 That should work it's not rotated yet so that's were it's hates it ever so slightly. 11:09.620 --> 11:11.930 And let's see what happens when we go ahead and play. 11:11.930 --> 11:17.520 Now we've only got 50 frames so I'm going to up this now to 200 just to see what happens. 11:18.450 --> 11:19.880 It turns out yes. 11:19.920 --> 11:20.320 There we go. 11:20.320 --> 11:22.410 The cone does indeed fall over. 11:22.410 --> 11:27.270 Now of course we could make things a bit more interesting we could make the floor a little bit more 11:27.270 --> 11:27.990 bouncy. 11:28.010 --> 11:32.580 And let's go to this cuber make that very bouncy in the friction a little low. 11:33.490 --> 11:33.910 There we go. 11:33.910 --> 11:39.310 So the cubes bouncing about was probably a bit too much bouncing this bouncing. 11:39.340 --> 11:40.150 This a new word. 11:40.150 --> 11:47.350 Never mind let's select these other objects and then copy from active which will be this first one again 11:47.650 --> 11:48.480 copy from active. 11:48.490 --> 11:49.180 Let's see what happens. 11:49.180 --> 11:50.880 Now they're a bit Pouncy Yeah. 11:50.980 --> 11:51.910 Excellent. 11:52.060 --> 11:52.960 Lots of fun. 11:52.960 --> 11:54.010 How did you guys get on. 11:54.010 --> 12:00.250 I hope you're getting the hang now of the physics engine as you can see it's got quite a bit of potential 12:00.520 --> 12:03.750 and quite a bit of confusing settings over here. 12:03.880 --> 12:08.950 But rest assured we'll get to the bottom of most of it and we'll have lots of fun whilst doing it. 12:09.130 --> 12:15.220 Please share your five falling objects in the discussions on the forum and I will see you guys in the 12:15.220 --> 12:16.280 next lecture.