attaching Nulls

[lightningad]

after staring at loads of tutorials i am beginning to wonder if i have missed something fundamental somewhere....

 

i need to use a Null, attached to the wrist of a character so that i can move the entire arm and hand model realistically, but i can't find out how to do this! I can create the Null, i just don't see how it relates to the model.

 

I'm not using any pre-made skeleton, as the model does not lend itself to that, and because i think you learn more from making your own than by dragging in anothers. I am also finding the concept of modelling in one window, and adding constraints in another to be rather bizarre...maybe i'm just not in the correct window?

 

 

any advice would be appreciated

[KenH]

I'm not sure what constraint you would use to do that, but the constraints can be made almost anywhere.....Action/Chor/Pose windows. It's just in a pose window, the constraints are saved "inside" the model and stay with it.

[lightningad]

Ken - what is a pose window? it was mentioned on a few tutorials as well. I am running on a mac and my system only shows the options of choreography,model,action or material windows.

[KenH]

If you right click(not sure about the mac) in a model window, you'll see New>Pose>Slider. This will open a new window where you can make a pose and/or add constraints to the model. The pose will be under the "User Properties" in the model and goes where ever the model goes.

[lightningad]

ahh, thanks Ken.

 

i think the fog is begining to lift!

[seven]

3DArtZ - please - explain to us how to make and use nulls!

giving a simple example - perhaps doing a WINK tutorial on it...

[Tunames]

I think what you are looking for is a kinamatic constraint in a pose or action window postion the null over the wrist select it,right click, select new contraint,kinamatic constraint, you'll get an eyedropper cursor ,select the forearm bone as the target and there ya go you've created a kinamatic chain also known as IK. which can be useful for animating when you want the arm to stay in place I prefer FK for the arms in most cases though.......Hope this helps

[Tunames]

Some one smarter than me please explain IK vs. FK

[Dearmad]

I think what you are looking for is a kinamatic constraint in a pose or action window postion the null over the wrist select it,right click, select new contraint,kinamatic constraint, you'll get an eyedropper cursor ,select the forearm bone as the target and there ya go you've created a kinamatic chain also known as IK. which can be useful for animating when you want the arm to stay in place I prefer FK for the arms in most cases though.......Hope this helps

This is reversed, I think, if you want the null to control the position of a model's geometry.

 

FK is basically that if you move the parent bone, the children move as you might expect, stiffly, as the parent bone moves; they rotate at the tip of the parent bone, and translate with the parent bone, but do not rotate independently unless you rotate them. If you move a child, the parent is unaffected. Lock all your bones in an IK chain to see this effect- or jsut don't conenct them.

 

IK is that if you move a child, the parent bone moves, more or less, as you might expect a connected object to move. If you move the parent, the children will have a tendency to remain in place, but will move. Connect the bones in a chain and you have this.

[JoshB]

Create your arm--shoulder bone, bicep, forearm, hand (these bones have CPs assigned to them--this controls your geometry).

 

Add your null and position it to the wrist. Nulls cannot effect geometry by themselves--however, they can effect other bones. Place the null at the wrist. One of a dozen solutions would be as follows.

 

For the handbone place an orient like constraint to the null:

 

This will cause the handbone to roll, and rotate just like the null.

 

For the forearm bone place a kinematic constraint to the null:

 

This will cause the tip of the forearm bone to reach the base of the null bone without effecting the chain.

 

Now when you move the null the forearm will move to reach the base of the null--and when you rotate the null the handbone will done the same. This is VERY basic--but it should give you enough info. to figure out a more complex method--should you desire one.

 

J

[lightningad]

Tunames and JoshB - you have both answered my question in slightly differing ways....but both bery useful and illuminating ways.

 

Thanks all for responding.