View Full Version : Animating the biped GLOBAL srt or not?

01 January 2007, 12:09 PM
Hey there guys,

Very stupid question here but i need my mind laid to rest right now. What's the orthodox way to animate the xsi biped? The thing is i have a problem with that "GLOBALSRT" thing, thats the pyramid between the feet. Is that thing suposed to move if you are animating a character? I find it more comfortable to not even touch it and animate away. This reduces sliding and the animation is better... but then why is the global thing there???

I basically want to know everyones different aproach to animating the xsi biped. How many leave the "GLOBALSRT" pyramid behind when animating? and those who don't, what exectly do you then do with it???

I'd greatly apreciate all of your different views and why you all do certain things... your reasons.


01 January 2007, 12:30 PM
I normally use the global srt for intially positioning a character, or if I need a quick and dirty walkcycle that I can repeat. This will mean some feet sliding but if you're far enough away (ie crowd shots etc) it doesn't show and can be a big time saver. I also use it if a character needs to be scaled, as everything lives underneath it, and scaling model nulls themselves can result in unexepected problems.

01 January 2007, 12:38 PM
hey there,
okay... i got you, you use it for quick and dirty animations right? What about the proper animations... how do you nhandle that?

01 January 2007, 12:47 PM
If its a hero walkcycle then I may use it to initally place the character but after that I will leave it alone. I always have one in my characters though, even if I'm building my own rigs as its useful for making global changes to the character.

the clue's in the name - Global S (scale) R (rotate) T (translate)

01 January 2007, 12:10 PM

to help us get on the same page,

I understand that it's important for the GLOBAL srt to be there, Totaly. What i'm really asking is it it practical to animate a character... say walking down a road WITH the Globalsrt or not? I've found that not animating the global SRT and leaving it behind while the character walks down the road works so well.

So i wanted to find out what you all do when animating. I wanted to make sure that not animating the GLOBAL srt was orthodox


01 January 2007, 03:47 PM
I think as a general rule, the model root should not be animated.

01 January 2007, 11:47 PM
I think as a general rule, the model root should not be animated.

yes, the model root should stay put. but the root isn't the same as global SRT.
this is how i animate:
1 make a walk-cycle
2 save it as an action(including the global SRT with Translate key) and bring it to mixer
3 in the mixer i cut the last frame on cycle so it won't repeat when it meets the "first" one
4 i use a script-formula to make the global SRT to automaticaly jump when one cycle is finished in order to keep the character walking to infinite if i choose to.

Also the global SRT is useful for repositioning the character into the scene. One cannot make a general rule as "when to animtae or not to" the SRT... it comes with experience and is very related with the every particular case. So i can only advice you to work as much as you can and maybe next time you'll bring us some of your experince too.
Good luck!

01 January 2007, 06:40 AM
I don't if this'll help...

What I usually do is draw and animate a 2D skeleton (in the shots I plan to do). Sometimes for more complicated movements, I ask help from one of the animators in our 2D department.

So when I have the action I want saved as an image sequence, I rotoscope it into XSI and animate it pose to pose (using global or local SRT depending on the need). Then I tweak the curves after...

Of course, not everyone can be expected to use 2D guides all the time, just pointing out another option.

Good luck with your work!

01 January 2007, 02:06 PM

Thanks for all the input there guys, The reason i ask is that i used to try to animate with the globals srt, then i recently got hold of a copy of Jeff Lew's animation DVD. The way his character reacted to animation is the same way the biped reacts when you animate it and not touch the global srt. I tried it out and animating withoiut touching the global srt is a breeze... there's no sliding and stuff.

I really wanted to find out what everyone else was doing when animating this so i dont meet problems in a long term project...


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