Animation diagnosis exercise #3

[robcat2075]

This one is a bit more involved than I might otherwise target, but our own forum member steve392 has daringly volunteered it for inspection, so have at it!

 

The centaur nature of the character complicates things a bit, but I think you can still examine this mostly in terms of a biped doing a standing jump. Which is a good basic body mechanics challenge for an animator.

 

There's quite a bit going right here. Can you spot what's going wrong?

 

side_jump.mov

 

3/4 view same jump

[bighop]

Is it that her head doesn't look up (that much) as she jumps?

[Rodney]

Thats a pretty tough character to animate from the get go.

 

We work with what we have here but the design of the character makes this one hard. On most centaurs I would expect the front legs to act more like arms. This isn't so much a crit of the design as it is a possible insight into the animation and the jump.

 

If the rear legs can be seen as bearing the majority of the character's weight during the time of the jump the rest of the diagnosis should be a little easier.

 

At a minimum the character's rear quarter/butt should move forward more to assist with the jump. The entire body crouching down in support of the anticipated effort to push the characters weight at the front upward as the front legs push up.

 

I'd say an anticipated movement back via all four legs should be followed by a movement down with the front. The rear should then follow through and assist as the front quarter launches up and off the ground.

 

Thats my initial diagnosis of the jump up.

There should be an adequate recovery as well.

 

Thats a fun one.

[TheSpleen]

there should be more bending of the knees at first. She seems to jump from her toes.

She should bend her knees more on the landing as well. it is more of a stiff legged hop to me than a jump.

[robcat2075]

I found a bit of footage of a horse doing the "Hi-O Silver" style jump which is somewhat like Steve's animation in that the back feet stay on the ground while the front feet go up.

 

http://www.youtube.com/watch?v=ZMtp9eFnb8w

 

But after watching it a bit it's all rather mysterious. The horse doesn't seem to be pushing off with the front feet much nor is it moving to counter balance its weight over the back legs.

[TheSpleen]

I found a bit of footage of a horse doing the "Hi-O Silver" style jump which is somewhat like Steve's animation in that the back feet stay on the ground while the front feet go up.

 

http://www.youtube.com/watch?v=ZMtp9eFnb8w

 

But after watching it a bit it's all rather mysterious. The horse doesn't seem to be pushing off with the front feet much nor is it moving to counter balance its weight over the back legs.

by that video it appears as though the horse merely changes it's center of gravity and uses it's hind legs as shock absorbers.

[AMSpector]

Apparently, a horse can shift its weight to its hindquarters and launch its front half into the air (using its head as the lead), without any effort from the front legs at all:

[Rodney]

But after watching it a bit it's all rather mysterious. The horse doesn't seem to be pushing off with the front feet much nor is it moving to counter balance its weight over the back legs

 

Not mysterious... a horse's weight/base is at its rear.

Shift that weight/draw it back and the front will automatically lift.

 

The problem with mythic creatures is that they don't quite fit into the realm of real world physics.

Case it point the Satyrs with the backward bending knees.

If you joined a Satry with a horse... that'd probably be closer to the reality of 'centaurs' than having human legs on the front of a horse. The front legs of a centaur would be more like arms than legs.

 

If you try this at home the results will be the same.

Go on try it. I'll wait.

 

Unless you are a considerable athlete...you can't push up very much with your arms. It'll be your weight and base that helps shift your torso and your legs/base will take over to push everything upward. As the horse has considerable weight and base at the rear the front is easily lifted.

 

Like most quadripeds Horses can walk on their hind legs but they usually have to be trained to stand on hind legs for more than mere moments unless provoked to fight or in heat.

[steve392]

This is very interesting and informative .I am sure this is going to help me get it to look a lot better and understand the way it should work much better ,keep going folks

[robcat2075]

Not mysterious... a horse's weight/base is at its rear.

Shift that weight/draw it back and the front will automatically lift.

 

There's just as much in the front as the rear and the horse is only barely moving back at all. Not enough to counter balance what is in the front.

[Jeetman]

I found a bit of footage of a horse doing the "Hi-O Silver" style jump which is somewhat like Steve's animation in that the back feet stay on the ground while the front feet go up.

 

http://www.youtube.com/watch?v=ZMtp9eFnb8w

 

But after watching it a bit it's all rather mysterious. The horse doesn't seem to be pushing off with the front feet much nor is it moving to counter balance its weight over the back legs.

 

After watching this a few times, I do see the horse pushing off but not upwards. It's pushing back to try to change it's center of gravity. The reason I think it looks mysterious is because of a second movement the horse makes. As the horse is pushing back with his front legs, he lunges slightly forward with his/her hind legs to try to get under the push from the front legs (much like a powerlifter does in a clean and jerk movement). The momentum the horse creates by pushing back with the front legs is then shifted instantly forward and up with a push from the hind legs. He/she didn't quite get under the push back and it caused him/her to fall forward. The movements are almost simultaneous which is why it is confusing.

 

That's my take on it.

 

George

[Rodney]

There's just as much in the front as the rear

 

I'm hardly an expert on horses so I'm not sure how to convince you that this is an incorrect statement if you are talking about the base of the horse. Weight on the other hand is pretty evenly distributed with a 60/40 ratio with dead weight in the front.

 

Horses have a base in the rear that they do not in the front. (Examine the differences in their front and rear legs closely and this is readily apparent). Hardly Trex porportions mind you but if that comparison helps... there you are.

 

Combine that base with the musculature and weight in the main body versus the head and natural leverage of the bones supports the weight down and to the rear.

 

 

More than anything this is a study in anatomy and bone structure.

The bones carry the weight no matter what the weight distribution is.

In this case, with the base being at the rear legs... the leverage flows from there.

 

Its interesting to note that a horse kick rearward demonstrates the legs operating very differently. For instance, a horse can continue walking forward while using its front legs but when using its back legs the front legs tend to stay firmly planted on the ground to maximize stability. I'm not sure I've ever seen a horse walk on its front legs.

 

My initial look for websites didn't turn up anything ideal for the discussion of weights/counterweighting etc. There is a lot of information out there. I did find this article from 3D world that introduces the subject of anatomy for 3D artists:

 

http://mos.futurenet.com/pdf/3dworld/TDW89_t_tips.pdf

 

If you purchase 3D world you may have already seen it.

[Rodney]

Books I don't have in my library but probably should have:

 

http://store.doverpublications.com/0486429806.html

[Gerry]

I just wanna know what her bikini bottom is covering!

[Rodney]

I just wanna know what her bikini bottom is covering!

 

Gerry wins the prize.

[alano]

I think your initial analysis of this as essentially a biped doing a standing jump is a good one for this character. That said, I'd start with the knees already slightly broken so they don't pop as she crouches. Bend the head forward, elbows back and stick the biped butt out which will push the rear hips rearward. Start the jump with the head, then the arms and finally the legs which will tuck in the biped butt thus pushing the rear hips forward. She also needs more settling time after the landing but maybe you didn't get that far.

 

The model, while well done, is disturbing.

 

Alan