How To Keep Feet From Sliding

[brucegregory]

What is the most straightforward method for keeping a set of feet, (connected to legs), firmly planted on the ground and prevent them from sliding? What is most direct method for using an animated walk cycle, and advancing the character, naturally, across the floor or ground, (an additive walk cycle, if you will)? I read somewhere that you can lock translation and rotation for any joint via some OP or something, which seems like that might keep feet steady until you desire to move them, but I can't find any other reference in the documentation or by searching the forum that addresses this issue.

Thanks for helping,

Greg Smith

[calin_casian]

you have to be carful how you key your foot because most of the sliding problem is in the way that houdini and other pakages interpolates between keys (in Houdini by default: cubic function). So you may want to go into channel editor and set that particular segment to "linear" function instead of cubic. IMHO you shouldn't worry about the sliding in the first animation pass, just get the timing right and fix the sliding later because you have to go to channel editor anyway to adjust your animation curves.

[edward]

I assume you're IK on your legs?

[brucegregory]

Edward:

Sorry for the delayed response. Yes, IK on the legs, and you can assume it is a simple biped rig.

Greg Smith

[edward]

Uh ... what Calin said ... it's all in the curves ...

[doc]

you have to be carful how you key your foot because most of the sliding problem is in the way that houdini and other pakages interpolates between keys (in Houdini by default: cubic function). So you may want to go into channel editor and set that particular segment to "linear" function instead of cubic. IMHO you shouldn't worry about the sliding in the first animation pass, just get the timing right and fix the sliding later because you have to go to channel editor anyway to adjust your animation curves.

13185[/snapback]

Just to add to Calin's comment, I usually set the default function to constant() and set my key poses.

Once I'm happy with the poses and the timing I'll change the functions of the curve to linear or cubic. You can you set the defaults in settings>main preferences>animation.

Luca

[Jason]

Also, dont forget the "Hold" function on the Playbar to key held poses. This is MMB on the playbar handle to hold all scoped channels. You *have* to channels scoped for this to work - if you don't nothing happens when you MMB drag and there is no message telling you have you have nothing scoped so it seems like it doesn't work.

So when you're setting up your initial walkcycle, plant the foot, MMB drag to when the foot should lift and set another key. And so on.

[Dezra]

Hi

Just to get my terminology right, what is a segment? Is it the part of the curve that resides between two keys or another name for the whole curve? If it is the former , is it possible to set the function of the curve (segment in that case) between two keys to a different type than the segment before it or after it? For example say I have 3 keys on tx. Is it possible to set the curve between the 1st-2nd keys to constant() and between 2nd-3d keys to cubic(). I've tried doing it but the whole channel curve gets converted. Maybe there is a not so obvious way to to that?

[thekenny]

Just to get my terminology right, what is a segment? Is it the part of the curve that resides between two keys or another name for the whole curve?

Yes, a segment is found between two keys. If you have one key you still have the ablity to set a segment function IF you select the the key itself. The function bit should be available via the channel Editor.

I think you need to break the key handles which control the slope of the curve between keys. You can press 't' to break a tie and then use the zero key to flatten if needed.

IMHO sliding feet is all in the keys. Keep at it you will find a way.

hth

-k

[Dezra]

I think you need to break the key handles which control the slope of the curve between keys. You can press 't' to break a tie and then use the zero key to flatten if needed.

IMHO sliding feet is all in the keys. Keep at it you will find a way.

hth

-k

14329[/snapback]

Thanks thekenny

I didn't know the break tie functionality existed. Just did a quick test and it is just what I wanted!

[edward]

Is it possible to set the curve between the 1st-2nd keys to constant() and between 2nd-3d keys to cubic(). I've tried doing it but the whole channel curve gets converted. Maybe there is a not so obvious way to to that?

14328[/snapback]

To answer your questions,

1. Yes

2. There is an obvious way. Select the segment (ie. the curve in between two keys) in the Graph Mode of the Channel Editor. At the bottom, there should be something that says Function: cubic() that becomes enabled. In the right arrow menu, click on it and choose constant(). Done.