Constant Keyframe & Peg Questions

2 burning questions.
Most tutorials on cut-out animation recomend checking the Set Constant Keyframes box in the preferences. Then recomend setting non-constant keyframes between moves in the timeline. What are the advantages of checking Set Constant Keyframes?
Also, what is the difference between a Peg and a Parent Peg. Do they have different attributes? Are there times when you would want to use one over the other? A pre-thanks for any help. Thank You

When you are keyframe animating you are essentually setting keys to create key drawings. Now that might sound confusing because the term key is used to mean two different things. A key drawing is a basic animation term for a drawing or picture that establishes an important pose in a sequence. I often like to call these boundary poses because they establish the boundaries of movements. If you can establish good strong key poses the animation is mostly defined and is in many cases totally understandable and viewable. It may not be complete or as smooth in transition but it is well defined. The part that is missing is the inbetween pictures or drawings that add that additional interest and smoothness to the motion. When you set keys as in keyframes you are setting parameters that also set up boundries to define the beginning and ending of a sequence. So the terms are similar but not exactly the same thing. A single key picture may be established by using many keyframe key settings.

Now non-constant segments are in fact instructions to the render engine as to how to create inbetween keys between two keyframe settings. In fact it is possible to have keyframes that are connected by constant segments and keyframes that are connected by non-constant segments and they can span the exact same sequence of frames for the same element. As an example, an animator may be tweening location keys and not tweening rotation keys for the same object between the same two frames. So to just automatically tween everything by default is not always what the animator wants done. But the animator does want to establish key poses and view and check the quality of those poses to see if the overall animation is working as desired. Then once the key poses are the way the animator wants them to look, they can then “fine tune” the animation by adding inbetweens and adjusting spacing that make sense or not adding unneeded inbetweens. Thus for keyframe animating using constant segments as the default is a more logical approach, you establish your key poses and get them right then you decide how you want to inbetween or not inbetween to add to your action, that is when you want to turn on a non-constant segment for that specific inbetweening situation. Animators don’t just inbetween to be inbetweening. Inbetweens are only added when they enhance the animation.

A peg is a sequence of containers that hold keyframe settings and the transition instructions between those settings (segments). Those keyframe settings describe to the TBS render engine how to display drawing or image objects frame by frame. Pegs can be independent elements or they can be integrated parts of drawing or image elements. But their basic purpose is the same, they contain sequences of keyframe settings and also the instructions for the transitions (inbetweens or no inbetweens as well as spacing) between keyframe setting pairs.

Pegs are also used as connectors to create control hierarchies. They connect elements. An element can be attached to another element in such a way that one element is the parent and the other element is the child. Two elements attached to the same parent element are called siblings (brother and sister). Children are influenced by their parent, what the parent does causes the child or children to follow. Parents are not influenced by their children. So a parent peg is used to establish a control relationship over subordinate elements (children).

Hierarchical structures can be very complex and are often referred to as a rig ( a puppetry term I believe). Children have parents who can be children of other parents who can be children of other parents and so on to establish a complex control relationship between a whole group of elements such as a cut-out characters body parts. I hope this helps you to have a clearer understanding of these important concepts. -JK

JK-TGRS Thank you for your response. Your generosity with knowledge is greatly appreciated. But, let me rephrase one of my questions. In the timeline mode where there is one button to add a Peg and another button to add a Parent Peg, at which occassion would you choose one over the other? Thank you very much.

The add parent peg button is a ‘left over’ from the pre-version 3.5 days of TBS. Its main purpose was to let you select drawing or image elements in the timeline and then in one click add and attach a peg to each of them.

This was important and useful when there were only independent peg elements and all pegging required adding a peg and attaching other element types to it. Since version 3.5, drawing and image elements now have integrated (embedded) pegs so they by definition have an included parent peg.

The button can still be used to add and attach a peg to any selected element and there is still a value in doing that as a bit of a time saver on occasion but it isn’t as significant a feature as it once was.

Independent pegs have important uses and are still valuable particularly for motion keyframing, like adding motion paths to cycles, they also are great as folders to help organize the timeline list and as hierarchical grouping connectors, but most of the usage of independent pegs pre-version 3.5 has now shifted to the integrated drawing and image element’s pegs which is a great enhancement. -JK