View Full Version : KickStarting a Harley

04 April 2009, 05:47 AM
Hello all, this is my fist animation post. This is a playblast, roughed out moves. I would love any and all feedback. I will be adding to this, essentially the guy is going to walk out of a bar, kickstart his harley and then drive off. I started with what I thought would be the most difficult, kickstarting. I know that I am getting some bad deformations and pinching in the shoulders and upper body, I plan on addressing that. The rig and skinned model is referenced into the scene so I can go back and fix bad spots easily.

Thanks in advance for the feedback.

04 April 2009, 12:36 PM
this might suck to hear... but ive never seen anyone start a bike with their left foot...


04 April 2009, 01:15 PM
MAV, do you mean you have never seen someone kickstart their bike from that side of the bike rather than straddle it or do you mean from that side of the bike with their left foot? I have owned two kick only harleys and I always kicked them from that side of the bike and I kicked with both my left and my right leg. I did a search on youtube for videos to reference and found that most of the examples were people using their right leg but some with the left.

04 April 2009, 04:48 PM
I've never kick started a motorcycle, but I'm wondering why the pedal depresses so easily the first few times, but is almost immovable the last time. Well, I can recall a pull-start lawnmower being like that. Motor cycles are the same maybe?

There's just a hint of overlapping motion between upper and lower body showing (and the cycle body). More of that (properly timed, of course) might help sell the weight and effort involved.

I'm also thinking that motorcycle is too far past the balance point for it to not fall over (away from him). A motorcycle is pretty massive. It seems to be rocking too easily.

You might consider shortening this to just 2 or 3 jumps instead of seven. Less to polish and less time for the demo reel watcher to analyze what is not right.

04 April 2009, 05:04 PM
robcat, thanks for the feedback. The kicking motion, where it looks easy and then not is a combination of things. You generally have to 'set' the pedal and the pistons into a position and you can do this be simply bringing your leg down, sometimes it doesn't 'catch' which means it swings through much easier. The 'big' jump is not as much that you can't bring the pedal through without that much weight but you use all that weight to get a really sharp, violent kickthrough to get the motor to catch. But I agree that there is too many of the little kicks. I plan to cut this into a few pieces using trax editor and then create a motion with a little kick or two and then one big one.

On the overlapping motion comment, can you give me a few more details on what you mean?

Thanks for weighing in!

04 April 2009, 01:26 AM
On the overlapping motion comment, can you give me a few more details on what you mean?

Describing it is something beyond mere text messages, unless you just mean "what is overlapping motion?" but think you know the term already.

Basically you got a guy hurling himself into the air so he can land on that pedal. But he's doing it bent over. I see his spine being treated mostly as a rigid unit with just slight bending at moments.

How does he get his mass moving fast enough to get off the ground? He coudl be doing more with that spine to anticipate into jumping. His ground leg does just a slight anticipation before the jump so he's not getting much from that. I bet if we tracked his hips on that last jump we'd find it travels pretty much same speed all the way up. No object tossed into the air can do that; it will decelerate all the way up until it falls back down. So it better start out fast.

We could claim his pedal leg is helping him climb up there, but that pedal doesn't drop even a millimeter when he puts his weight on it. In fact, it seems to be drifting slightly up; that kills any illusion of force being applied there.

Not much of what I said here is about overlapping motion, but overlapping motion would enter into all of it to prevent that weightless rigid look.

This is a motion you should actually do yourself feel to how parts of your body are being moved and acted on. Keep doing it until you feel the weight in every bone and the motion of every joint. What's holding back when something else is trying to go?

That's always done more for me than reference footage.

04 April 2009, 03:11 AM
robcat, thank you very much for such a detailed response. I am actually re-working the animation as we speak, this is very helpful.

Thanks again.

04 April 2009, 03:01 PM
Thanks again for the feedback. I have made this a little shorter, with less 'setting kicks' and also tried to pay more attention to the spine, hips and some of the overlapping actions. There are some pops that I need to smooth out but I think this is better.

Camera angle one

Camera angle two

04 April 2009, 01:30 AM
Yeah, the pops are a problem, hard to tell which way those are going to go. The pop itself suggests two differing keyframes, too close together. Or perhaps a keyframe has been left on "hold" interpolation. (That's an A:M term, I dont' know what the Maya equivalent is.)

random thoughts...

-anytime you're jumping, don't leave the ground with a bent leg. It should be pushing until the last tippy toe can't reach any more. The leg should leave the ground as straight as it can be without creating an IK pop.

-This is a very interesting body mechanics challenge because it introduces the element of that pedal which has varying resistance, unlike a step which is solid.

-I think you're closer, but i wouldn't put this on a reel yet. The upper body still doesn't look right. i wish I had more specific corrections, but to get there I'd have to sit down and try animating the same move myself and go thru that whole discovery process. (Which I probably won't do.) An A-list animator could frame thru that and isolate the trouble, but I'm not one of those.

-Actually, except for the spine popping, this would pass with a lot people. We've certainly seen game animation that didn't nail the body mechanics.

- you know the pedal goes thru his ankle at the end, right?

- the rocking of the cycle itself may be too linear and too much for such a heavy object.

-I'd table this one, do some other shots, and then return to this and see if your eye has become more discerning. And hopefully get some other specific feedback besides mine. There's never a shortage of people on CGTalk to tell you what's wrong with the latest Dreamworks movie but they never seem to be around when soemone needs actual advice.

04 April 2009, 01:34 AM

Again, muchas gracias for such details feedback. Your point about a scarcity of advice when you actually need it is too true. It really makes you think that people are viewing and feel it is so bad that they don't know where to start. ah well.

I have let this go for a few days so will probably go back and give it an eye again this weekend. I will post my progress.

Where in Dallas are you? My parents have lived in the area for over twenty years and I lived in Lakewood for a few years after college (right behind the Lakewood theater).


04 April 2009, 04:16 AM
Where in Dallas are you? My parents have lived in the area for over twenty years and I lived in Lakewood for a few years after college (right behind the Lakewood theater).

Not far from there. I'm on Gaston Ave.

05 May 2009, 03:51 AM
I have done some more work on this, made some updates, added weight to the motion as well as some other bits. I think this is heading in the right direction, maybe getting close?

Thanks to all for the feedback.

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