I'm currently trying to practice stop motion and improve my skill. I have a few questions:
When animating a walk, is it essential to have a rigging, or are tie downs sufficient enough to do the walk?
Do you all buy a rigging system or do you create your own? I didn't think to put a screw into my armature for rigging, should I start over and make a new one with a nut?
How do you practice stop motion? Specifically controlling the armature and attaining a sort of "fluid" look. Is there any exercise that is most effective?
I'm new to this as well, but I would think a rig would help a lot. I'm sure some of the more experienced members will chime in on this subject. When looking at behind the scenes videos on YouTube, I've seen quite a few rigs being used on walk cycles and such. I guess it depends on the quality of your armature as well. I'm in the process of building mine and am adding a spot on the waste for rigging in the event I'll need it. As far as buying a rig, they seem awful expensive. I would build my own. It doesn't have to be pretty, it just has to work. Just my opinion.
I would recommend practising animation with tie-downs, not rigging. There's lot of reasons to use rigging for animation- such as heavy characters or small feet. But it's an extra level of complication that you should avoid if you're still learning. When your characters feet are tied down, you get a natural movement a little easier, because you can move the body and the foot stays in place, like it would if the character had weight.
The best exercise in my opinion is still a simple walk- there are a lot of animation techniques packed into this one action (weight, overlap, consistency, etc.), and walking is a natural movement you see everyday, so it's easy to see if your animation is working or not.
The other reason walking is good practise is because a good walk has repetition- each step is exactly the same. I don't think it's immediately obvious, but one of the hardest things to do in stop-motion is animate the exact same thing for hours without changing or modifying anything. You get two steps in to a 10 step shot and think "maybe something else should happen to make things interesting". This is ok sometimes, but the discipline of animation sometimes requires you to do the shot exactly how you planned it, and this is a skill that takes time to develop.
I agree with Evan. Tie-downs are a great way to go. The rig often ends up getting in the way and distracting from the animation. The rule of thumb is that if it is possible to do without a rig, never use a rig. If you must use a rig, hide it. If you can't hide it and must use it, pay someone to remove the rigs for you...haha. Really though, doing it without rigs is best. Once you can do that you will be able to enjoy rigs when they come as they will allow you to do things you weren't previously able to do.
As far as smooth animation goes, just keep moving forward in continuously increasing or decreasing increments and in a specific (often curved) path. Think about the bouncing ball and pendulum and it will all make sense soon enough.