Hi. My first post. Yes, you need the trax editor. It's funny, cause I was in need of the very same thing a few months back and after weeks of scouring the internet, I could not find one tut on the trax so I used Maya help to try and learn it.
It's actually quite simple but I'll give you a quick overview.
1. Before keying anything, select all the handles/joints that will have "keys" on them. Create a "character set" out of them.
2. In the channel box for each of the "keyed" items, you'll now notice that the attributes are "yellowed" out. This means they are part of a "character set". If you right-click any of the attributes(scale, rotate, etc.) you can add or remove from the set.
3. In the bottom right corner of the screen, you'll notice an arrow where you can turn on/off your character set. Set it to none(I'll explain this later)
4. Key in some cycle(remember, when making cycles, the first frame and last frame are NOT identicle, rather, the last frame is ONE frame short or the first frame. This is because when you loop the "clip" in the trax editor, you don't get a "repeated" first frame, resulting in a "skip" in animation)
5. After the cycle is complete, open up the graph editor. Check how many frames the cycle is. If it's, say, 14 frames, then key in a value for every "keyable" attribute for everything in the character set at frame 1 and frame 14, even if there are no keys for certain joints/controllers(this in a sense, "isolates" the "clip", so you don't get joints interpolating due to future keys. Also, make sure there are no keys going past the end frame for anything.
6. Load up your trax editor and on the bottom right next to the timeline, select the character set to "Your Character".
7. You'll notice that ALL your keys will appear in your timeline, for all controllers/joints that you "keyed". This is why we didn't create the cycle with the Character set "on". It gets hard to manage your keys with keyticks all over the timeline.
8. Select the "+" symbol in the trax editor that says "load existing character set", and select "create clip" with animation curve checked. Name your clip.
9. You now have a clip in which you can scale, cut, blend into other clips, etc.
10. To access all your clips, open up General Editors>visor. You can delete/rename them there.
11. To add clips to the trax, goto clip>..... all your existing clips should be there.
12. To redump the keyticks of your clip back to your timeline for further editing, select the clip and rightclick "activate keys"
This is just a simple start, hope it all makes sense. YOu can do much more with the trax editor, like layering clips, create Sub character sets(for reusing upper body or lower body motions), keying "into" clips.
I used the trax extensively in creating my first character. You can download the cycle test here if you want to see: