WEBVTT 1 00:00:00.740 --> 00:00:04.770 Hello and welcome to another episode of scripting for artists. My name is civilian. 2 00:00:04.770 --> 00:00:08.100 And in this episode we will talk about modal operators. 3 00:00:08.109 --> 00:00:11.110 So the reasons free episodes of scripting for artists 4 00:00:11.110 --> 00:00:13.680 have been part of the open up project. 5 00:00:13.690 --> 00:00:17.110 You can read about this on blended at ERG in the new section. 6 00:00:17.170 --> 00:00:19.510 This open up project was all about providing some 7 00:00:19.510 --> 00:00:23.480 relief during the corona lockdown and slowly but steadily, 8 00:00:23.480 --> 00:00:27.480 at least here in the Netherlands things are opening up a little bit again. 9 00:00:27.490 --> 00:00:29.990 So this means the open up project is also coming to 10 00:00:29.990 --> 00:00:32.860 an end because this is the last episode for now. 11 00:00:32.870 --> 00:00:35.390 I wanted to do something a little bit more complex. 12 00:00:35.400 --> 00:00:37.580 So that is why we're looking at model operators. 13 00:00:37.580 --> 00:00:40.250 They are a bit more complex but there is a very powerful and 14 00:00:40.250 --> 00:00:43.450 they opened up a whole range of new possibilities for your adults. 15 00:00:44.440 --> 00:00:49.960 So first of all, what is Model? I looked it up on Dr go and it gives me some information. 16 00:00:49.960 --> 00:00:54.270 Some useful links. Well, you apparently Model is also kind of fabric. 17 00:00:54.280 --> 00:00:55.730 I'm not that interested in it. 18 00:00:55.740 --> 00:00:59.850 But the second link was to the Merriam Webster dictionary and it has 19 00:00:59.850 --> 00:01:04.620 all kinds of definitions from Model for example of or relating to modality. 20 00:01:04.620 --> 00:01:06.060 So let's take a look at that. 21 00:01:06.640 --> 00:01:10.480 A modality. The quality of state of being model. Yeah, well thank you very much. 22 00:01:10.490 --> 00:01:14.450 But it also says the classification of logical propositions 23 00:01:14.460 --> 00:01:17.130 according to their asserting or denying the possibility, 24 00:01:17.130 --> 00:01:20.760 impossibility, contingency or necessity of their content. 25 00:01:21.840 --> 00:01:25.550 I still don't quite get it. But it has something to do with logic. 26 00:01:25.560 --> 00:01:27.690 So let's take a look at another dictionary in this 27 00:01:27.690 --> 00:01:31.490 case the Oxford learner's dictionary and it says for modality. 28 00:01:31.500 --> 00:01:36.150 The particular way in which something exists is experienced or is done. 29 00:01:36.540 --> 00:01:41.390 And this starts to look more familiar. If you think about edit motor object mode 30 00:01:41.790 --> 00:01:45.960 it is a particular way in which blender exists at that moment. 31 00:01:46.440 --> 00:01:47.460 For example pressing G. 32 00:01:47.460 --> 00:01:51.600 In edit mode will move a vertex whereas an object mode it will move an 33 00:01:51.600 --> 00:01:55.500 object so things can have different meanings depending 34 00:01:55.500 --> 00:01:57.140 on the mode that blender is in. 35 00:01:57.420 --> 00:01:59.530 And this is also what a model operator does. 36 00:01:59.540 --> 00:02:04.260 It basically adds another mode to blender which is then defined by your operator. 37 00:02:04.340 --> 00:02:07.900 It can take over your complete blender interface and swallow 38 00:02:07.900 --> 00:02:10.509 up all the user input events that there are. 39 00:02:10.520 --> 00:02:13.320 Or it can just respond to one or two things and then 40 00:02:13.320 --> 00:02:16.140 pass on the rest of blender so that it behaves it's normal. 41 00:02:16.160 --> 00:02:19.350 Let's see what that looks like in code so that things become 42 00:02:19.350 --> 00:02:22.410 a bit more concrete to demonstrate how a model operator works. 43 00:02:22.410 --> 00:02:24.460 Have made a small little add on. 44 00:02:24.540 --> 00:02:27.710 It's just a silly little thing and the ingredients will look pretty familiar. 45 00:02:27.710 --> 00:02:29.900 But now it has a little info. It imports. 46 00:02:29.900 --> 00:02:34.050 Beep I it has the operator and then it registered and unregistered when needed. 47 00:02:35.240 --> 00:02:38.220 So of course the interesting bit is inside the operator. 48 00:02:38.220 --> 00:02:42.320 It starts in the same way as you're used to with bill I. D. Name br label. 49 00:02:42.320 --> 00:02:45.460 The naming is consistent with the I. D. Name your idea. 50 00:02:46.040 --> 00:02:49.160 But instead of an executed has a model and an invoke 51 00:02:49.540 --> 00:02:51.770 now mind you it could also have an execute function. 52 00:02:51.770 --> 00:02:54.940 It is not the lack of execute function that makes this model. 53 00:02:55.410 --> 00:02:57.600 The invoke function is called the blender whenever 54 00:02:57.600 --> 00:02:59.810 the operator is run from the user interface. 55 00:02:59.810 --> 00:03:03.470 So from a hotkey or a menu item or a button on a panel 56 00:03:03.650 --> 00:03:06.730 and this is the function where you would start the model operator. 57 00:03:06.830 --> 00:03:08.410 This invoke function does two things. 58 00:03:08.410 --> 00:03:11.740 It tells blenders Window manager that we should receive events. 59 00:03:11.940 --> 00:03:16.650 And then by returning running model it was blended that we want to run model 60 00:03:17.040 --> 00:03:19.680 and that's the basic of getting a model operator. 61 00:03:19.690 --> 00:03:23.870 Now when there is a window manager event like a mouse move click key, 62 00:03:23.870 --> 00:03:25.930 press anything like that. 63 00:03:25.940 --> 00:03:28.770 Our model function will be called and of course it gets the 64 00:03:28.770 --> 00:03:32.960 context but it will also get information about which event triggered it. 65 00:03:33.340 --> 00:03:37.320 So these events objects are documented in the python api reference that if you 66 00:03:37.320 --> 00:03:41.160 want to find that for the version of blender using at the moment just go 67 00:03:41.160 --> 00:03:45.360 to help and then python api reference and that will bring you here you search 68 00:03:45.360 --> 00:03:49.120 for event and then you find to be part of types of event structure. 69 00:03:49.130 --> 00:03:51.500 This has all kinds of useful properties that are set 70 00:03:51.500 --> 00:03:53.760 by blender before it sends the event to our code. 71 00:03:54.040 --> 00:03:57.190 So from movement of the mouth we have a few different options. 72 00:03:57.190 --> 00:03:59.000 We have mouths previous X. 73 00:03:59.010 --> 00:04:02.640 So as the previous location of the mouth combined that with mouse X. 74 00:04:02.650 --> 00:04:04.390 And then you get a sense of the motion 75 00:04:04.390 --> 00:04:07.330 that somebody did rather than the absolute position. 76 00:04:07.340 --> 00:04:09.230 There's the mouth region X, 77 00:04:09.230 --> 00:04:13.590 which is the region relative horizontal location of the mouse and there's mouth X. 78 00:04:13.590 --> 00:04:16.660 Which is the window relative horizontal location of the mouse. 79 00:04:17.339 --> 00:04:20.130 The most important property here is the type. 80 00:04:20.140 --> 00:04:22.250 This tells us what kind of event this is in 81 00:04:22.250 --> 00:04:24.480 the first place is the left miles is middle miles, 82 00:04:24.480 --> 00:04:27.240 right mouse keyboard, trackpad events here. 83 00:04:27.240 --> 00:04:28.380 Also the timer event. 84 00:04:28.380 --> 00:04:32.240 This one can be very important if you want to do something every once in a while. 85 00:04:32.250 --> 00:04:36.390 So that could be every second, every millisecond every 30 seconds. 86 00:04:36.390 --> 00:04:37.350 Just what you need 87 00:04:38.040 --> 00:04:42.300 back to our code. I want to print some different things based on the type of the event. 88 00:04:42.310 --> 00:04:48.370 So if event type is mouse move, then I just print mouse move with the mouse, X and 89 00:04:48.540 --> 00:04:53.540 Y coordinates. If the event type is left mouse, I say left click at X and Y. 90 00:04:53.550 --> 00:04:56.800 Else if the event type is in this set and this is a 91 00:04:56.800 --> 00:05:00.330 quick and easy way to just check for a bunch of different values. 92 00:05:00.340 --> 00:05:04.230 So if it's either right mouse or escape, I just say right click stopping, 93 00:05:04.240 --> 00:05:05.540 it may also be escape. 94 00:05:05.550 --> 00:05:07.100 I don't care. This is fine. 95 00:05:07.110 --> 00:05:08.440 Then it says return finished, 96 00:05:08.440 --> 00:05:11.370 which tells blender that we want to stop the model operators. 97 00:05:11.370 --> 00:05:14.630 So at this time it will no longer be receiving any events. 98 00:05:14.640 --> 00:05:16.220 If that does not happen, 99 00:05:16.230 --> 00:05:19.600 it returns running model just like the invoke function did 100 00:05:19.610 --> 00:05:22.160 to indicate that it should still be kept running. 101 00:05:22.840 --> 00:05:25.020 Let's see what we can get into print. 102 00:05:25.030 --> 00:05:29.240 Have installed the add on and enabled it in the user preferences as you can see. 103 00:05:29.250 --> 00:05:32.580 So here we are in blender and I've also put my terminal 104 00:05:32.590 --> 00:05:35.240 on the screen so you can see what it prints Now. 105 00:05:35.250 --> 00:05:37.360 This is still without are operated running. 106 00:05:37.360 --> 00:05:41.220 You can see that the menu items and everything is responding to our clicks. 107 00:05:41.230 --> 00:05:43.030 This problem normally responds. 108 00:05:43.040 --> 00:05:47.690 I pressed F3 to go through the search box and then I looked for the silly example, 109 00:05:47.700 --> 00:05:50.060 I press enter so you can see that it already 110 00:05:50.060 --> 00:05:53.160 received its first mouth move event in the terminal. 111 00:05:53.640 --> 00:05:55.670 And when I move the mouse it keeps going. 112 00:05:55.680 --> 00:05:57.540 Remember the difference between the window 113 00:05:57.540 --> 00:06:00.130 relative and the region relative coordinates. 114 00:06:00.140 --> 00:06:02.940 Three D view port is a region. The outline is a region. 115 00:06:02.940 --> 00:06:04.530 The properties panel is a region. 116 00:06:04.540 --> 00:06:08.490 So if you want to do something that is relative to the three D view port. 117 00:06:08.500 --> 00:06:11.660 The region relative coordinates will probably be what you need. 118 00:06:11.840 --> 00:06:14.400 Now I'm printing the window relative coordinates. 119 00:06:14.400 --> 00:06:16.500 So that means that so that means that 120 00:06:16.510 --> 00:06:20.580 in the bottom right corner the coordinates are 00 121 00:06:20.590 --> 00:06:25.360 and in the top right we get to what is almost the resolution of my desktop. 122 00:06:25.840 --> 00:06:28.940 One thing you may have noticed is that blender doesn't respond anymore 123 00:06:28.940 --> 00:06:32.500 to these mouths over is because we swallowed up all the events. 124 00:06:32.510 --> 00:06:38.760 Also when a middle click and drag to change the view port, it doesn't do anything 125 00:06:39.240 --> 00:06:43.560 but it does show a left click and right click and then it stops and now 126 00:06:44.740 --> 00:06:49.700 it's back to normal Again, our operator has stopped and blender responds as usual. 127 00:06:49.710 --> 00:06:54.460 One thing you might notice is that one click caused to print statements 128 00:06:55.040 --> 00:06:57.610 so the print isn't exactly correct. 129 00:06:57.620 --> 00:06:59.150 It's not a left click, 130 00:06:59.160 --> 00:07:04.130 it's the mouse down and then the mouse up event that you receive again the python, 131 00:07:04.130 --> 00:07:06.190 api documentation to the rescue. 132 00:07:06.200 --> 00:07:08.560 There is a value property that will tell you more 133 00:07:08.560 --> 00:07:10.850 about the type of event that you're looking at. 134 00:07:10.860 --> 00:07:12.760 Let's add this to our print statement 135 00:07:13.340 --> 00:07:18.300 who are in the code. We know it's about the left mouse so we can leave the left in there. 136 00:07:18.300 --> 00:07:23.450 But here we just do event value at a certain location. 137 00:07:23.940 --> 00:07:26.760 And then instead of right click, let's just say 138 00:07:27.140 --> 00:07:30.460 event type, event value 139 00:07:30.940 --> 00:07:32.650 and we'll still be stopping there. 140 00:07:34.740 --> 00:07:35.850 Reload the script. 141 00:07:37.140 --> 00:07:38.100 Rerun it. 142 00:07:38.410 --> 00:07:39.960 The mouse move hasn't changed. 143 00:07:40.840 --> 00:07:43.150 But you can see there is a left press and left 144 00:07:43.150 --> 00:07:46.860 release and then a right mouse press we can run it again 145 00:07:47.540 --> 00:07:49.340 like press left release 146 00:07:49.460 --> 00:07:53.270 and from your press escape we can escape, press and then it's over. 147 00:07:53.280 --> 00:07:55.790 So that's the basics of modal operators. 148 00:07:55.790 --> 00:07:58.160 Let's start looking at something a bit more useful. 149 00:07:58.170 --> 00:08:01.000 We're going to follow what is pretty much in the template. 150 00:08:01.000 --> 00:08:04.360 So if you go to the scripting tab in blender and then templates python, 151 00:08:04.370 --> 00:08:07.760 you will find a bunch of examples for modal operators. 152 00:08:07.940 --> 00:08:11.010 So we're going to do is follow the view through the operator. 153 00:08:11.010 --> 00:08:14.670 But I'm going to do things in a slightly different way than is in this code. 154 00:08:14.680 --> 00:08:18.350 And then you can just make up your mind about which approach you like more 155 00:08:18.740 --> 00:08:21.300 First a little demo of what it does. 156 00:08:21.310 --> 00:08:25.540 I've run the code in the template and then press F three simple view operator. 157 00:08:25.550 --> 00:08:26.090 You presenter? 158 00:08:26.090 --> 00:08:27.970 It starts in the top left corner, 159 00:08:27.970 --> 00:08:31.260 you can see the offset which is now moving if I 160 00:08:31.260 --> 00:08:34.429 move the mouse in the X direction of the window, 161 00:08:34.440 --> 00:08:36.440 it also moves the view port in the X. 162 00:08:36.440 --> 00:08:37.549 Direction of the world. 163 00:08:37.840 --> 00:08:39.460 And the same for why? 164 00:08:40.539 --> 00:08:43.480 Now if I rotate then you can see the difference 165 00:08:44.740 --> 00:08:46.510 are moving the X direction and you can see 166 00:08:46.510 --> 00:08:49.460 that the movement is still in the world X direction 167 00:08:49.670 --> 00:08:51.550 and the same for the Y direction. 168 00:08:53.240 --> 00:08:57.550 If a right click we end up where we started off so that's a council 169 00:08:58.140 --> 00:09:00.160 and of course left click is confirmed. 170 00:09:00.540 --> 00:09:04.920 So let's look at the invoke function. It does a bit more than we did in our code. 171 00:09:04.930 --> 00:09:07.720 Of course, this only works in the three D view Putin. 172 00:09:07.720 --> 00:09:11.340 That's the first thing that's being checked on if contacts of space data, 173 00:09:11.340 --> 00:09:12.920 that type equals for you three D. 174 00:09:12.920 --> 00:09:13.930 Then the work is done. 175 00:09:13.940 --> 00:09:18.370 Otherwise a warning is shown and the operator is canceled personally. 176 00:09:18.380 --> 00:09:20.060 I would flip this. 177 00:09:21.440 --> 00:09:21.640 Yeah, 178 00:09:22.040 --> 00:09:22.240 yeah. 179 00:09:22.640 --> 00:09:25.060 Into if it's not three D. 180 00:09:25.840 --> 00:09:29.950 Give a warning stop and then invent the whole thing. 181 00:09:30.940 --> 00:09:33.470 So now that we know it's a three D view port, 182 00:09:33.480 --> 00:09:37.750 we can access context of space data and call it the three D. 183 00:09:37.760 --> 00:09:39.660 And then we can get the three D. Region. 184 00:09:40.040 --> 00:09:43.350 So a space is made up of regions and in the three D view 185 00:09:43.350 --> 00:09:46.690 port case a region is the three D view but also a header, 186 00:09:46.690 --> 00:09:49.090 maybe a full term, maybe some panels on the sides. 187 00:09:49.100 --> 00:09:50.780 And we have to have the three D view port. 188 00:09:50.780 --> 00:09:53.500 If you want to change its camera around then changing the three 189 00:09:53.500 --> 00:09:56.950 D view port camera only works if you're actually looking through it, 190 00:09:56.960 --> 00:09:58.760 if you're looking through the same camera, 191 00:09:59.040 --> 00:10:00.940 this whole thing has to do something different. 192 00:10:00.940 --> 00:10:04.150 It would have to move the same camera around to fix that it 193 00:10:04.150 --> 00:10:08.890 just switches it over to perspective you and then finally we have to store 194 00:10:08.900 --> 00:10:12.940 the initial location of the mouse so that we can track the motion 195 00:10:12.940 --> 00:10:17.250 of the mouse relative to the point where it was when this operator started 196 00:10:17.460 --> 00:10:21.780 and then we have to remember the original location of the view port camera so 197 00:10:21.780 --> 00:10:25.370 that we can restore that when we right click and it has to be cancelled. 198 00:10:25.380 --> 00:10:29.950 And then finally we have the known bit which is registering this operator as 199 00:10:29.950 --> 00:10:34.700 a model operator and then returning running model as a side note in python, 200 00:10:34.710 --> 00:10:38.090 it's possible to just write stuff to self dot something. 201 00:10:38.100 --> 00:10:42.860 You don't have to declare it as a property, you can just add a new property like this. 202 00:10:43.740 --> 00:10:47.680 So these kind of things would not be stored by blender if you do this on an object. 203 00:10:47.690 --> 00:10:50.110 So it's very limited in its use but for 204 00:10:50.110 --> 00:10:53.370 storing temporary data on an operator like this, 205 00:10:53.380 --> 00:10:54.150 it's fine. 206 00:10:54.540 --> 00:10:56.650 Now let's look at the model function and the 207 00:10:56.650 --> 00:10:58.660 structure of this is pretty much the same as 208 00:10:58.660 --> 00:11:03.470 we did before we look at different event types and then execute a little bit of code. 209 00:11:03.480 --> 00:11:05.510 We can change some things around in this code 210 00:11:05.510 --> 00:11:07.810 to make it a little bit easier to understand. 211 00:11:07.820 --> 00:11:12.750 This bit is only used down here, so let's move it there. 212 00:11:13.040 --> 00:11:14.480 It's the same thing as before. 213 00:11:14.490 --> 00:11:18.310 It just gets the three D view port region so that the view 214 00:11:18.310 --> 00:11:22.240 location that is the camera that is used for the view port, 215 00:11:22.250 --> 00:11:24.380 The location of it is set back to the 216 00:11:24.390 --> 00:11:27.620 initial location when we press right mouse or escape. 217 00:11:27.630 --> 00:11:29.420 This causes it to cancel it, 218 00:11:29.420 --> 00:11:32.240 then clears the header text that is set while 219 00:11:32.240 --> 00:11:35.150 we're moving the mouse and then it returns council. 220 00:11:35.150 --> 00:11:39.050 So that tells blender that this operator is no longer supposed to be running 221 00:11:39.350 --> 00:11:41.160 in the case of the left mouse. 222 00:11:41.240 --> 00:11:45.180 All that's done is that the offset taxes removed from the header. 223 00:11:45.220 --> 00:11:47.880 And then blender is told that we're finished 224 00:11:47.890 --> 00:11:51.750 because during the interaction during the mouse move we're 225 00:11:51.750 --> 00:11:55.050 already changing the view port confirming doesn't need to 226 00:11:55.050 --> 00:11:57.560 do anything because the view port already changed. 227 00:11:57.580 --> 00:11:59.860 And then finally we get to the interesting bit. 228 00:11:59.940 --> 00:12:02.290 What should happen when the mouse is moving 229 00:12:02.540 --> 00:12:04.590 this line is already doing a lot. 230 00:12:04.600 --> 00:12:08.320 So let's split that up into a few easily digested parts. 231 00:12:08.330 --> 00:12:12.720 First of all it's converting event of mouse X and event miles wide to 232 00:12:12.720 --> 00:12:16.500 a vector so that we can do some three D math with it. 233 00:12:16.660 --> 00:12:21.210 Of course the camera location in the three D view port Is a 3D position. 234 00:12:21.210 --> 00:12:24.140 So there's a vector and converting things to a vector. 235 00:12:24.140 --> 00:12:26.850 Makes all those computations a little bit easier. 236 00:12:27.740 --> 00:12:27.940 Yeah 237 00:12:28.740 --> 00:12:30.260 so we have a mass position. 238 00:12:32.740 --> 00:12:33.060 Okay. 239 00:12:34.840 --> 00:12:35.040 Yeah. 240 00:12:35.740 --> 00:12:35.950 Okay. 241 00:12:37.840 --> 00:12:41.350 Which is the vector consisting of mouse X miles y 242 00:12:41.360 --> 00:12:44.460 and zero because we don't have a three dimensional mouse. 243 00:12:45.640 --> 00:12:45.880 Yeah 244 00:12:46.840 --> 00:12:52.980 the amount that the mouse moved by is self that initial mouse minus mouse position. 245 00:12:52.990 --> 00:12:55.950 So that is the difference between the starting position of 246 00:12:55.960 --> 00:12:58.060 the mouse and the current position of the mouse. 247 00:13:00.330 --> 00:13:05.050 And then finally we scale the mouse movement because otherwise you would move 248 00:13:05.060 --> 00:13:08.740 at around one blender unit for every pixel that you move your mouse. 249 00:13:08.750 --> 00:13:11.770 So how do you get to this number? Well that's just trial and error. 250 00:13:11.780 --> 00:13:16.490 You first tried without the scaling and then you see that things move way too quickly 251 00:13:16.500 --> 00:13:19.960 and then he starts killing it down and you get to something that works for you 252 00:13:20.340 --> 00:13:22.560 finally self executed called. 253 00:13:22.840 --> 00:13:25.620 Normally blender would do this for us and it will 254 00:13:25.620 --> 00:13:28.820 still do this when we call this operator from python. 255 00:13:28.830 --> 00:13:33.810 However, there is nothing stopping us from calling execute ourselves as well. 256 00:13:33.960 --> 00:13:37.660 We'll take a look at what execute is doing exactly in a moment 257 00:13:37.940 --> 00:13:41.750 and then finally the header taxes said to offset with the X, 258 00:13:41.750 --> 00:13:44.960 y and z coordinates of self offset. 259 00:13:45.640 --> 00:13:48.090 This notation is called percent formatting. 260 00:13:48.100 --> 00:13:51.750 It consists of a format string than a percent and then one 261 00:13:51.750 --> 00:13:54.930 or more things that are supposed to go into the format string. 262 00:13:54.940 --> 00:13:58.920 So in this case our format string has three fields they start with a percent. 263 00:13:58.930 --> 00:14:02.170 The end with an f to indicate a floating point and 30.0.4 in 264 00:14:02.170 --> 00:14:05.350 there means that we want to have four decimals in the number. 265 00:14:05.740 --> 00:14:08.620 So let's take a look at that offset and the execute 266 00:14:08.620 --> 00:14:11.750 function because those are the final parts we haven't seen yet. 267 00:14:11.760 --> 00:14:14.910 The offset is a property as we've seen before. 268 00:14:14.920 --> 00:14:18.420 It's a float vector property and this is imported here 269 00:14:18.430 --> 00:14:21.200 as from b point props import flood vector property. 270 00:14:21.210 --> 00:14:25.750 So it's just a shorter version of writing be pie dot props dot flood vector property. 271 00:14:25.940 --> 00:14:28.410 So the name is offset the sizes three, 272 00:14:28.420 --> 00:14:32.400 which means that we have three values in our float vector. 273 00:14:32.410 --> 00:14:36.560 And this is because the view port camera position is of course three dimensional. 274 00:14:36.740 --> 00:14:39.490 And then finally we look at the execute function again, 275 00:14:39.500 --> 00:14:42.090 it gets the 3D region from the context. 276 00:14:42.100 --> 00:14:44.180 What's going on here is a little bit confusing 277 00:14:44.180 --> 00:14:47.740 because the property type is float vector property, 278 00:14:47.900 --> 00:14:52.550 but the value that it produces is not a vector, it is something else. 279 00:14:52.640 --> 00:14:54.870 So that means that if we want to do some vector math, 280 00:14:54.870 --> 00:14:56.810 you first have to convert it to a vector. 281 00:14:56.820 --> 00:14:58.260 So that's what's happening here. 282 00:14:58.270 --> 00:15:00.610 It's converted to a vector and then it's added 283 00:15:00.610 --> 00:15:02.970 to the initial location of the view port camera. 284 00:15:02.980 --> 00:15:05.360 And that new location is then assigned to the view 285 00:15:05.360 --> 00:15:08.500 location property of the three D view port region. 286 00:15:08.510 --> 00:15:12.730 So as a quick overview in the invoke, we did some preparatory work, 287 00:15:12.740 --> 00:15:15.560 we registered that this is a model operator. 288 00:15:15.570 --> 00:15:17.920 Then in the model function when the mouse moved, 289 00:15:17.920 --> 00:15:21.060 we computed an offset and then in the execute function, 290 00:15:21.070 --> 00:15:24.010 we add that offset to the initial location of the view 291 00:15:24.010 --> 00:15:27.350 port camera to compute the new view port camera location. 292 00:15:27.740 --> 00:15:32.140 Now, I wanted to show you how we could call it, execute function from python. 293 00:15:32.150 --> 00:15:35.750 But the problem is that in the console you can see that 294 00:15:35.760 --> 00:15:38.890 the operator is there and that we can even pass an offset. 295 00:15:38.900 --> 00:15:42.560 But if you try to use it, let's see what happens 296 00:15:42.940 --> 00:15:46.140 if you do it like this, then you get an error. 297 00:15:46.160 --> 00:15:50.290 That space console object doesn't have an attribute region three D. 298 00:15:50.300 --> 00:15:53.160 And that is because currently when you run it here, 299 00:15:53.740 --> 00:15:56.600 the context is set to the console. 300 00:15:56.610 --> 00:16:00.360 So context of space data is a space console and 301 00:16:00.360 --> 00:16:02.760 other space few three D in the error message. 302 00:16:02.760 --> 00:16:08.370 You can see that the execute function is actually corporate blender 1 18 is the 303 00:16:08.370 --> 00:16:13.860 problematic one and that is indeed getting few three D dot region three D. 304 00:16:13.940 --> 00:16:18.290 A console doesn't have original 3D property. So that is the issue here. 305 00:16:18.300 --> 00:16:22.870 But it does show the idea behind it that you can have an execute function on there, 306 00:16:22.870 --> 00:16:27.560 that you can call from Python and then invoke to get something that is interactive. 307 00:16:28.040 --> 00:16:32.740 As I said in the beginning, a model operator takes over all of blender 308 00:16:32.940 --> 00:16:36.360 but it's also possible to do that selectively whether 309 00:16:36.360 --> 00:16:39.020 an event should be passed through to blender itself 310 00:16:39.030 --> 00:16:41.540 or should be used by the modal operator that's 311 00:16:41.540 --> 00:16:44.570 determined by the return value of your model function. 312 00:16:44.740 --> 00:16:49.470 This operator now only responds to mouse motion and we cannot zoom in or out. 313 00:16:49.740 --> 00:16:53.080 So let's say we want to allow the scroll wheel up 314 00:16:53.090 --> 00:16:56.170 and scroll wheel down to be passed through to blender so 315 00:16:56.170 --> 00:16:59.280 that blender can take care of the zooming for us and 316 00:16:59.280 --> 00:17:02.280 then all the other events that they're still gobbled up. 317 00:17:02.280 --> 00:17:05.920 So you can't do shift a to get the AD menu for example, 318 00:17:05.920 --> 00:17:09.450 while you're also moving around, this is quite simple to do 319 00:17:09.640 --> 00:17:13.770 first. We have to figure out what event of type is that belongs to the scroll wheel. 320 00:17:13.839 --> 00:17:15.760 So either you look that up in the python, 321 00:17:15.760 --> 00:17:18.910 api reference or you do like me and you just added print 322 00:17:18.910 --> 00:17:22.630 statement that prints out all the event of types that you see. 323 00:17:22.640 --> 00:17:26.930 So by that you can figure out that it will up mouse and well down mouse. 324 00:17:26.930 --> 00:17:28.720 Those are the events were interested in. 325 00:17:28.730 --> 00:17:31.900 Now if the event is of any of these two types, 326 00:17:31.910 --> 00:17:34.740 we can just return paths for this tells blender. 327 00:17:34.750 --> 00:17:36.700 Just use the event is normal. 328 00:17:36.710 --> 00:17:40.300 This we could also do for the mouse move we could do also about 329 00:17:40.300 --> 00:17:45.080 default and then the model operator would be more like an addition to blenders, 330 00:17:45.080 --> 00:17:46.170 regular behavior 331 00:17:46.440 --> 00:17:49.290 rather than taking over all of the user interface. 332 00:17:49.300 --> 00:17:52.740 And this is up to you to determine what your adult should do. 333 00:17:52.750 --> 00:17:55.090 An example of passing through all the events you 334 00:17:55.090 --> 00:17:58.830 can find in the timer example also in templates, 335 00:17:58.830 --> 00:18:00.930 python and than operator. 336 00:18:00.930 --> 00:18:05.140 Model timer using a timer is basically the same as you've seen before, 337 00:18:05.140 --> 00:18:09.880 is just adding yet another registration function and of course when you stop, 338 00:18:09.880 --> 00:18:13.610 you also have to unregistered your timer this time it's the execute 339 00:18:13.610 --> 00:18:17.380 function that returns running model So you can start a model operator 340 00:18:17.380 --> 00:18:21.450 not only from an invoke but also from an execute and here 341 00:18:21.450 --> 00:18:25.690 you see self timer equals window manager of the event timer. 342 00:18:25.700 --> 00:18:26.170 Ad, 343 00:18:26.840 --> 00:18:29.620 this is the number of seconds between timer events that 344 00:18:29.620 --> 00:18:31.530 you want to have and you have to pass the 345 00:18:31.530 --> 00:18:34.320 window so that it knows which window your operator belongs 346 00:18:34.320 --> 00:18:37.960 to and then model handler ad and return running model. 347 00:18:37.970 --> 00:18:40.130 And then when you want to cancel your timer, 348 00:18:40.140 --> 00:18:43.140 you have to tell the Window manager instead of event timer. 349 00:18:43.140 --> 00:18:48.240 Ad, you say event timer removed with the thing that you got from event timer. 350 00:18:48.240 --> 00:18:51.210 Ad and in your model function you will get an event with 351 00:18:51.210 --> 00:18:54.060 typist timer and there you can do all kinds of stuff. 352 00:18:54.070 --> 00:18:57.830 We can see here in the model function is that by default it returns passed through. 353 00:18:57.840 --> 00:19:01.140 So this does not get in the way of your blender usage, 354 00:19:01.150 --> 00:19:05.660 except that it changes the theme all the time, so it might get in the way after all. 355 00:19:06.040 --> 00:19:09.220 So this is it for this episode of scripting for artists. 356 00:19:09.230 --> 00:19:12.660 If you have any questions or remarks, please leave a comment below. 357 00:19:12.670 --> 00:19:16.390 If you want to get more help or you want to just talk about 358 00:19:16.390 --> 00:19:20.940 what are good approaches when it comes to add ons and python and scripting 359 00:19:20.950 --> 00:19:26.090 pop over to blender dot chat is the official blender chat platform and there 360 00:19:26.090 --> 00:19:29.270 is the python channel where you can ask all these kind of questions, 361 00:19:29.270 --> 00:19:31.560 as many people helping each other out over there. 362 00:19:31.840 --> 00:19:35.050 In any case, this is it for now, See you later.