Motion Tracking & Object Tracking inside Cinema 4D: Solving and Calibrating the Object

Share this video
  • Duration: 08:11
  • Views: 4396
  • Made with Release: 18
  • Works with Release: 18 and greater

Once the Manual tracking is complete, and all the requirements are met, it's time to Solve and Calibrate our 3D Object Track.

Once the Manual tracking is complete, and all the requirements are met, it's time to Solve and Calibrate our 3D Object Track. Always remember, that you need 7 very good tracks to successfully solve an Object, but it's better to have a few more, for safety.



After a fair amount of manual labor, I have managed to track all the manual trackers that belong to the object. Let me scrub so it goes a bit faster. There you go, you can see them moving over their features. Fantastic. So how do we solve for this object? Well let me show you. Go to the motion tracker and go to the 2D tracking manual tracking and you will see all the user tracks so make sure they're selected. They were but I'm showing you you can do this by clicking and then shift clicking over here and we have all of them selected. The next thing we need to do is go to the motion tracking menu and add an object tracker to the scene and let's call this weapon. You don't have to but why not? And with the weapon selected, go to trackers and because we have all these trackers selected, we can see them in the viewport. Click on assign selected and then all these manual tracks are going to be assigned to the object tracker called weapon. Now if I got to the motion tracker, you can see that they have the prefix weapon and that's because in the options I turned on this. If I turn it off, you won't be able to see it, if I turn it on. Currently, we only have one object tracker so we won't get confused. If you more than one, it's good to know which ones belong where. Fantastic. So don't forget, in our motion tracker we have this on, lock solve data before we started tracking these manual tracks and now all we have to do is go to weapon, reconstruction, and press this button. It's going to take a couple of hours, no I'm joking. It's just going to take three seconds and it's already done. That's it. That was it. Now, look at this. You can see that the axis of the weapon is moving because now we have key frames, these are the calculated key frames. Let's take a look at something before we do anything else. You can't see the object here, can you? Now let me zoom out and zoom out and zoom out. The object is somewhere down here. You can see it moving. Now, that's odd. Well, actually it's not odd. How can the tracker know that our object is of a certain size? This can be a cannon that's 200 miles down the road or this can be a very small weapon that someone's holding in their fingers. So we need to actually calibrate it for size. Let's go and do that. Here we are in our viewport and we can go and add some of these calibration tags. So, right click, motion tracker tags, and what I'm going to do is assign a vector constraint and what I'm going to do here is scrub to a frame where I can see, there you go. I can see these two, this one and this one, and I think that this one and this one are about 15 centimeters away. So I'm going to grab this, put it here, click here. You have to click first and then drag it and it has a snapping. If I release here, it's going to snap. What I'm going to do, I'm going to forget about the axis for now and I'm going to say the length is known and it's 15 centimeters. When I say okay, you won't see anything really happening here but when I go to my top view now, let me deselect this so I can go in, now you can see that the weapon is pretty much where we expect it to be because we calibrated the camera approximately and now we're calibrating the weapon approximately and that's good enough to see a, so to speak, realistic view of what's going on. Now, of course, I can tell this that it's on the Z-axis as well so this will allow me to calibrate so that I can go and assign some sort of object. Well, let's go and see how that works. So let's go to the preview and what can I do, I want to make it a bit fancy here. I am going to create some text and the text is going to say weapon and make it a child of the weapon object and make sure all the coordinates are zeroed out. Good and you can see that it's moving. There you go, fantastic. I'm going to do certain adjustments here. For example, I'm going to add an extrude object so it's nice and 3D. Select this and scale it down, scale it, scale it, scale it. Now let's see again, you can see it's moving with this lady but I'm going to rotate it so it's 90 degrees that way and then I'm going to move it that way and then bring it down then you can see now that she is carrying a weapon. Look at that. Now, because we have all these nulls here, you can always go to auto features and make them invisible. Look at that. Isn't that interesting? Now, if you want to fine tune it, there are a couple of tricks you can do. So I'm going to select this null here. Go to the top view and you can see that the word is sort of aligned to this null and that's all fine. Let me go to another view and say all right this is the back end of it. I need to find that little null, there you go. Where is that null? Oh, it's over there. So, our orientation is actually quite good but basically you eyeball it by going to one of your top views, selecting your nulls, and adjusting the model to fit your 3D object. So, that is how we solve and how we calibrate our 3D object and if you actually create a proper model like I did for the final view, you can place it here and it looks absolutely fantastic. I'm going to just copy and paste it in here. So, I have my weapon here. I modelled this. Fantastic, isn't it? Anyway, I'm going to copy it and go to my other scene and paste it. I'm going to make it a child of weapon and get rid of the text and I'll need to make sure that the coordinates are zero, zero, zero and zero, zero, zero. Now let's see how this looks. Not bad. I think I need to adjust it's position ever so slightly because this is in the front so I'm going to move it that way and a bit further down. Let's see what this does. There you go and I need to rotate it ever so slightly and again I need to follow the rule I set earlier. You can see that it's ever so slightly off because I need the tip to be here but I need the back to be over here. So, I'm using my nulls to place it properly. Let's go and see in another view if we can do some corrections over here. Let's see. And let's a take a look in our 3D view if we did something interesting and yes we did. The good lady is holding a weapon and I can now make these invisible, rewind, press play, and enjoy my masterpiece.
Resume Auto-Scroll?