Let’s look at your composite so far. To do that, you need to render your tree as a flipbook into Framecycler.
Note If you’re using the PLE version of Nuke, you will not be able to preview your work using Framecycler, as it’s a blocked feature under the PLE license. If that’s the case, simply click Play in the Viewer and wait for it to cache. This might not result in perfect playback.
1 . Select Merge1 and press Alt/option-F to render a flipbook of the selected node and load it into Framecycler.
2 . In the Flipbook panel that displays, leave the frame range at 1-100 and press oK.
A Progress Bar displays to show you the frame count as they are rendered. This is slightly different than the way you used Framecycler in Chapter 1 and previously in this chapter, as you are now actually processing a tree and not just loading Read or Write nodes into Framecycler.
What’s happening now is the tree is being rendered into a temp directory, and those temp frames will get loaded into Framecycler. When you close Framecycler, those frames will be deleted.
3 . When Framecycler loads, press the Spacebar to play the clip.
Notice the dark flash that occurred during the playback. It starts at frame 42. You will need to make the doll mimic this light fluctuation. So far all the values you set for various properties were constant values—not changing from frame to frame.
Now you need to change those values over time. For that purpose you have keyframes.
4 . If Framecycler is still open, close it.
cReATiNg ANimATioN WiTh keyFRAmes
Keyframes specify that you want animation. To do this, the property needs to change its value over time. So if you want your image to have a Blur value of 20 to begin with and then, at frame 10, to have a value of 10, you need to specify these two pieces of information: a value for frame 1 and a value for frame 10, and the application will inter-polate the in-between values.
In Nuke, practically every property can be keyframed. You are going to create another Grade node and use that to change the brightness of the doll branch to match the changes to the lighting in the background.
1 . In the Viewer, go to frame 42 by clicking the Timebar (FigUrE 2.50).
FIGURE 2 .50 Move to frame 42 using the Timebar.
2 . Select Grade1 and press G on the keyboard to create another Grade node.
Your tree should now have a new Grade node in it called Grade2 (FigUrE 2.51).
FIGURE 2 .51 grade2 is inserted after grade1.
tip If, unlike my tree, your tree is really messy, it will be hard for you to understand the flow of information and therefore read your tree. Sure, this is a simple tree. But if it were bigger, and you saved it and went back to it over the weekend, things might start to no longer make sense. Keeping an organized tree is always a good idea.
Frame 42, which you are on at the moment, is the last frame of bright lighting you have before the background starts to darken. This will be the location of your first keyframe, to lock the brightness of the doll to the current brightness level.
3 . In Grade2’s Properties panel, click the Gain property’s Animation menu and choose Set Key (FigUrE 2.52).
Note You could have
This creates a keyframe for the four values (R, G, B, and Alpha) associated with the Gain property. Notice that the field turns a blueish color—this is to show that a keyframe is present on this frame for this property (FigUrE 2.53).
The Timebar also displays a blueish-colored little box to indicate on which frame you have keyframes (FigUrE 2.54). The markings on the Timebar are shown for all open property panels that have keyframes. To see the keyframes on the Timebar for a specific node, make sure only that node’s Properties panel is open in the Properties Bin.
4 . Advance one frame by hovering over the Viewer and pressing the right arrow on your keyboard.
Notice that the color of the property’s Gain field is now showing a subtler blue color (FigUrE 2.55). This indicates that there is animation for the property, but there is no keyframe at this point in time.
FIGURE 2 .55 A light blue field indicates that this property has animation, but no keyframe at the current frame.
5 . Play with the Gain slider until you reach a result that matches the doll’s brightness to that of the background. I stopped at 0.025.
A keyframe is now automatically added. once the first keyframe is set, every change in value to the property will result in a keyframe on the frame you are cur-rently on. Notice the color of the numeric box changed from the light blue color to a bright blue color, indicating a keyframe has been created for this frame.
6 . Advance another frame forward to frame 44 and adjust the gain again. I stopped at 0.0425.
7 . Repeat the process for frames 45 and 46 as well. I had 0.41 and then 1.0.
We have now created several keyframes for the Gain property, resulting in anima-tion. The animation can be drawn as a curve in a graph called an Animation curve.
The X axis will represent time and the Y axis value.
Let’s set the Animation curve for this property in the Curve Editor.
8 . Choose Curve Editor from the Gain property’s Animation menu (FigUrE 2.56).
You can see the curve for the animation you just created (FigUrE 2.57). The Curve Editor is explained in more detail in Chapter 6.
9 . Click the Node Graph tab to go back to the DAG.
Look at Grade2. What’s that on the top right? Notice it has a little red circle with the letter A in it (FigUrE 2.58). I wonder what that’s for? It’s an indicator, which is explained in the next section. values is to click in the field and then use the
FIGURE 2 .56 Using the Animation menu to load a curve into the Curve Editor.
FIGURE 2 .57 This is what an Animation curve looks like.
FIGURE 2 .58 Node indicators can be very useful at times.