Animating Gmasks


Hi everyone, Grant Kay here for the Smoke Learning Channel. In the previous video, we looked at the different mask combinations. This included combining masks, subtracting masks and intersecting masks. In this video, weíll take a look at the different type of animations available when it comes to working with Gmasks. If you would like to follow along, please click the link in the YouTube description to download the Gmask setup. Or if you are watching the podcast version of this video then type the link displayed in your internet browser. I have created a two second black segment and added ConnectFX to it. I have also added a Gmask node into the ConnectFX flow graph. Select the Gmask node and press the LOAD button to load the downloaded setup through the file browser. Double-click the Gmask node for its controls. So I am going to keep this simple with a few shapes as we have a lot of ground to cover. When it comes to working with Gmasks, you have two types of animation. You have object animation, which is animating the mask as a whole object. And than you have Shape Animation, which is animating each of the vertices on the maskís spline. Because of the variety of animation levels, you need to understand the structure of the Gmask. Select the ConnectFX schematic view and press ESCAPE to bring up the Gmask Schematic. This type of schematic is very similar to the Action Schematic. This basically shows the objects in the Gmask node and how they relate to each other. So in terms of animation, all your object animation is kept in the Axis node. The geometry node is the actual shape spline but it also keeps the spline animation. The other benefit is that you use this nodal structure to combine and concatenate a bunch of object animations together. For example, you could have one axis node controlling the overall mask movement and a series of nodes controlling any secondary movement. Iíll connect some nodes later on to make this clear. Now since each Gmask is comprised of a geometry and Axis node, it is important to remember that in order to delete a mask, you need to delete the Geometry node and the Axis node. To the bottom right of the interface, you can choose the selection mode and press delete when necessary. Undo any deletions you have made with COMMAND+Z. It is not mandatory but seeing Gmask schematic is really handy when working with more than one Gmask. Now letís do some simple animation. You can select the shape in the schematic or just click it in the viewer. When it comes to object animation, you can use the Auto-key button or hold K and click the slider to add a keyframe. So Iíll just animate the rotation of this object. Letís spin it on its Z-rotation channel. So object animation is handled by the Axis and you can adjust it on screen or in the transformation controls. This is pretty much the same as Axis behavior in Action or using the 2D transform node. And just to confirm, if you switch to the Animation menu and press SHIFT+TAB to expand the selected channels, you will be able to see the animation curves for the selected Axis. Click the animation button to return to the Gmask menus. Now letís focus on shape animation. One of the first things that catch most people out is that shape animation is not connected to Auto-key. So it does not matter if Auto-key is on or off, you will still animate the vertices of the shape. The geometry is expecting changes overtime if you make adjustments on different frames. This is what we get when I scrub the time-bar. If you want the shape to stay constant and not animate over time, just enable the CONSTANT SHAPE button. Any animation will be wiped off the shape and it will keep its shape from the current frame. Any adjustments you make will not animate the shape over time. If you want the shape to start animating again, just disable the CONSTANT SHAPE button. Now Iíll go to the first frame and position the vertices. Next, Iíll move five frames forward and reposition the vertex points. So there is the shape animation. Because it is possible to have animation in literally thousands of vertices for a single shape, the animation is consolidated into a single shape channel by default. Switch to the Animation menu and press SHIFT+TAB to expand and focus on the shape channel. So this curve illustrates the speed at which the shape animates overtime. If you did want to see the animation curves for every vertex, switch back to the Gmask menus. Disable the SHAPE ANIMATION button. Now go back to the Animation menu. A SPLINE hierarchy will appear for the selected shape. When you expand this out, you will reveal each vertex channel and you have access to all the animations for each individual vertex. This is not something you may want all the time. So switch back to the Gmask menus and re-enable the SHAPE ANIMATION. This will covert all the vertices channels into the single shape channel. Just click CONFIRM. Switching back to the Animation menu, youíll see that the shape channel is back. You can manipulate animation timings to your liking but Iíll set the extrapolation to REVERSE CYCLE. This will just ping pong my shape animation indefinitely. Scrub the time-bar to see the result. Letís go back to the Gmask menus. So we have looked at object animation and shape animation. Letís look at combining all the animation together. Select the Axis node of the second shape. Letís move it to the left of the spinning diamond shape. In order to make the second shape inherit the animation of the spinning diamond, drag a connection from first Axis to the second one. This means that the object animation of the diamond axis is driving all the Axis nodes it connects to. Pay attention to the direction of the arrows on the connection to see what is driving what. If we scale Axis 1, it scales both shapes. So we have shape animation and object animation. You can easily add another level of animation to this. Letís say we want these shapes to go up and down. Under the Object menu, change the pull down from GEOMETRY to AXIS. Click the ADD button. Now parent this Axis to the diamond Axis. The Gmask schematic clearly shows us the hierarchy of control. Now ensure that Auto-Key is on. At the first frame, position the objects down and to the left. At the middle of the composite, push the objects to the top and middle of the frame. And finally at the end of the comp, push the objects down and to the right. When we scrub the time-bar, you will see a combination of all the animations from the various different nodes. This is how you can concatenate loads of simple movements into one complex animation. So how can you apply this to a task such as rotoscoping a person moving across the screen? For example, you could have one main axis node, which follows the personís overall movements. You can than focus on simplifying the job by having lots of shapes for the arms, legs and head. By parenting the main axis to the shapes, all the shapes will have the main animation as well as their own individual animation. So combining various levels of object animation and shape animation does have its advantages. Coming soon in the next video. You can add motion blur to your animated Gmask on a series of different levels. This is very useful when masking a moving target with motion blur or motion graphics creation. Comments, feedback and suggestions are always welcome and appreciated. Thank you for watching and please subscribe to
the Smoke Learning Channel for future videos.

2 Replies to “Animating Gmasks”

  1. NEW #AutodeskSmoke Video – Animating Gmasks in #Smoke2015 – Check it out! – http://youtu.be/B8vFNEbaJEI

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