Join Steve Wright for an in-depth discussion in this video Camera tracking preparations, part of NUKE Compositing: Alien Portal.
Before we can do our camera tracking we need to do some preps to kind of sweeten the shot for the camera tracker. So let's cruise over here, get a little working space, let's add a dot here as a home for our camera tracker. So we'll come down here and select the camera tracker, and I'll move it over there and I'll switch my viewer to the camera tracker node. If you do not have NUKEX you cannot perform the camera tracker steps in this video but you can use the results of it in the following videos.
So let's open up the camera tracker property panel I've moved the properties bin up here now so I'll double-click on this, we're now on the properties bin looking at the camera tracker property panel. I'm going to go to the settings tab and turn on preview features so we can get a sense of what the camera tracker is looking at. I don't want any points out here in the sky because the sky represents a vague, bland area with lots of bouncing data points so I need an ignore mask for the sky so the camera tracker doesn't look at the sky.
So we'll do that with illuma key, back to the node graph I'm going to select the same point here and come to the keyer tab, I'll shift-click on the keyer node I'll move the keyer node down here and camera tracker over there to kind of keep things a little bit neat. Ok, let's go take a look at our keyer. I'll hook my viewer up to the keyer node and then let's go to the property panel to see what we have. Switching the viewer to the alpha channel I'll now hold down on the darks to something like about so, OK, and we'll pull up on the whites, harden that matte, OK, something like that.
OK let's say we like that. We'll go back to the node graph and what I need to do is hook that up to the mask input of the camera tracker node. OK now if we look at the camera tracker node, switch back to the RGB channels. If we double-click on the camera tracker node to look at the property panel we'll now go to the camera tracker tab and tell it that the mask is going to be the mask alpha. Now do you see? Some of the tracker points jumped off the sky.
You have a couple left over here because there's actually a key on some light posts there. But the large, bland uniform sky is now masked off. Now let's go back to the settings tab and increase the number of features to something like 300, so we've got some more points. Now I want to make sure that I have a good, uniform distribution of trackers. So let's go over here where we've got lots of ceiling and floor as it were, and see if we can't make the tracker appreciate a more uniform distribution.
We'll go back to the node graph and I'm going to add a grade node right here to set up the clip to sweeten it up for the camera tracker, alright? So, let's add a grade node and then I'll hook it in here right above the camera tracker. Now let's double-click on the grade node to start setting the properties. Now as I turn the gain up watch how the points spread out. So I'm making this more attractive to the camera tracker.
I'd also like to have some more stuff down here so let me drop the gamma a bit, let's see if some of those points don't pop down there, there we go, there, that's nice. OK. We've prepared the the clip for the camera tracker. So in the next movie we'll do the camera tracking.
Each step of the process is rich in valuable production techniques, but is best for artists who are already familiar with NUKE. For more training on the basics, see Nuke X Essential Training.
- Compositing the alien character
- Creating holdout mattes
- Camera tracking
- Animating the portal rays
- 3D rendering the effects
- Adding interactive lighting
- Animating a flashing light
- Finishing a NUKE composite