how to make a boomerang spin?

[rossk]

I was working on a little short animation where a character throws a boomerang... and ran into some problems on making the boomerang spin. Basically I want to be able to position the boomerang in several different places (ex: I want the boomerang over here, at this angle) and then use the curves or some sort of pose to control the speed and direction with which the boomerang spins along its axis as it travels between these points.

 

I was thinking of some sort of rig for the boomerang that allows me to make its position and orientation seperate from the spinning.

I've tried several things with no success... I don't really know whats going on... but it seems that the spin of the boomerang gets weird when the x-axis rotation curve crosses the white-line curve (w-axis?)...

 

Thanks for any help,

--Ross

[robcat2075]

I was working on a little short animation where a character throws a boomerang... and ran into some problems on making the boomerang spin. Basically I want to be able to position the boomerang in several different places (ex: I want the boomerang over here, at this angle) and then use the curves or some sort of pose to control the speed and direction with which the boomerang spins along its axis as it travels between these points.

Boomerangs pretty much spin one axis. I'm not sure I understand the problem.

 

 

I was thinking of some sort of rig for the boomerang that allows me to make its position and orientation seperate from the spinning.

but spinning is orientation

I've tried several things with no success... I don't really know whats going on... but it seems that the spin of the boomerang gets weird when the x-axis rotation curve crosses the white-line curve (w-axis?)...

I'd change the rotation channels to Euler instead of Quat . It's done in the properties for that bone I think.

[ddustin]

Ross,

I used the approach in this link to control wheel spin via an expression, a null and pose slider.

http://www.hash.com/forums/index.php?showtopic=21797&st=30

It would give you the control over the rotational speed of your boomerang.

 

There were a bunch of other potential solutions as well.

 

Robcat is right when he says you should use the Euler rotation.

 

Expressions are really cool when you understand them.

 

David

[rossk]

Thanks!

Yeah, I guess what I meant by orientation is controlling the rotation of the boomerang in the 2 axises not dealing with the spin of the boomerang... so if spin is a rotate on the boomerang's x-axis, I want to be able to independantly change the y-axis and z-axis rotation without touching the x-axis spin part at all.

 

What's the difference between Euler and Quatern(?) rotation channels? I've heard something about gimble lock with Euler? But Euler allows you to set larger rotation values (like 720) without it reverting to 0 degrees rotation?

 

Thanks for the link ddustin, it looks like a good solution. I'll work on that later today... right now I'm late to my job though!

[robcat2075]

Thanks!

Yeah, I guess what I meant by orientation is controlling the rotation of the boomerang in the 2 axises not dealing with the spin of the boomerang... so if spin is a rotate on the boomerang's x-axis, I want to be able to independantly change the y-axis and z-axis rotation without touching the x-axis spin part at all.

 

Easiest solution is to have a spin bone that is a child of the bone you use to position the boomerang

 

[attachmentid=17511]

look at rotate-z channel of spin axis bone for control of spin separate from position.

 

 

What's the difference between Euler and Quatern(?) rotation channels? I've heard something about gimble lock with Euler? But Euler allows you to set larger rotation values (like 720) without it reverting to 0 degrees rotation?

Quat does better interpolation between weird angles, like a shoulder bone might have to do. It can't do 0 to 360 degrees of rotation in just two keyframes, however. Euler can do 0 to anything in two keyframes

flyingBoomerang.zip

[rossk]

Excellent, thanks Robert!

I know how to change between quat and euler in the options menu, which affects the entire project (I think)... is there any way to have my character use quat rotation channels and the booomerang use euler?

 

And-- Which type of rotation do you usually use as a default? Quat, Euler, Vector?

 

Thanks again Robert!

 

I'm also trying the method offered by David. Right now I'm taking a quick break on that though to download the expressions tech talk... since I've forgotten a bit about how to do those (like how to choose the null's position as one of the variables for the expression controlling the z-axis rotation).

 

Thanks again both!

--Ross

[robcat2075]

Excellent, thanks Robert!

I know how to change between quat and euler in the options menu, which affects the entire project (I think)... is there any way to have my character use quat rotation channels and the booomerang use euler?

Don't change the whole project

 

Make a rotation key for the bone (to create a channel) and then right-click on it's rotation properties.

 

[attachmentid=17513]

 

And-- Which type of rotation do you usually use as a default? Quat, Euler, Vector?

Leave everything at the Quat default except for things like wheels or propellers or boomerangs that need to spin many times. Those are good choices for Euler.

[ddustin]

Excellent, thanks Robert!

I know how to change between quat and euler in the options menu, which affects the entire project (I think)... is there any way to have my character use quat rotation channels and the booomerang use euler?

 

And-- Which type of rotation do you usually use as a default? Quat, Euler, Vector?

 

Thanks again Robert!

 

I'm also trying the method offered by David. Right now I'm taking a quick break on that though to download the expressions tech talk... since I've forgotten a bit about how to do those (like how to choose the null's position as one of the variables for the expression controlling the z-axis rotation).

 

Thanks again both!

--Ross

 

Ross,

If you email your boomarang, I'll see if I can set up the spin control for you.

Once you see how it works you'll be amazed how easy it is.

Course if you want to figure it out yourself you will ultimatley be better off.

 

I'm going to dinner then some volleyball, but should be able to look at it later.

 

David

[rossk]

Robert-- Thanks, that really helped me out on understanding how to deal with that stuff.

 

David-- Thanks for the offer! I'll watch that expressions video quick and then take another go at doing it myself, but if I can't get the expression to work then I'll take you up on your offer.

 

--Ross

[rossk]

Haha, my trouble with expressions was alleviated by realizing that the "show properties triangle" option should be enabled so that I can access the null's translate x property... I knew building expressions seemed more difficult than before

 

Thanks David! That is a nice pose-based solution for the spinning boomerang.