Digital humans the art of the digital double
Ever wanted to know how digital doubles are created in the movie industry? This course will give you an insight into how it's done.
# 1 13-11-2003 , 04:46 AM
Registered User
Join Date: Jun 2003
Posts: 8

car animation/model help!

i am new to maya and trying to animate a car crash as a visual aid for a school assignment. 2 questions:

1. Are there any tricks that would turn the wheels of the car in relation to the distance that the car travels.

2. Is there an easy way to define the path that the car travels other than just keyframing it?

I would appreciate any tips on this: drumstyk1@hotmail.com
AIM: Drumstyk1

P.S. My models are obviously really basic, so if any of you have some spare models of any types of cars and you want to help out your fellow man...i would greatly apreciate it!!! (It would be used in my high school physics class)

THANKS GUYS!!
~Eric

# 2 13-11-2003 , 05:02 AM
NitroLiq's Avatar
Moderator
Join Date: Nov 2002
Location: New York
Posts: 2,133
1. Check out some of the freebie video tutorials on set driven key (SDK). They might give you some ideas of having the car "drive" the rotation of the wheels (no pun intended).

2. Draw a cv curve from the top view and then select your car and the path. Go to animate>motion paths>attach to motion path. Your car should now animate along the path you drew.


"Terminat Bora Diem, Terminal Auctor opus."
# 3 13-11-2003 , 03:00 PM
Alan's Avatar
Moderator
Join Date: Oct 2002
Location: London, UK
Posts: 2,800
your first question is answered in this book I used to have around, it gives you the equation perfectly and then you can just put it into an expression and hey presto turning wheels... I dont have the book but I just tried this out on paper and it might work.... but dont quote me on that!

Ok let d be diametre of your wheel, pi is 3.14, m is distance travlled and n is the number of rotations of your wheel.

m = n * pi * d
so the distance travelled is the number of rotations times pi times the diametre of the wheel.

thus:

n = m / pi *d (i think that's right)

this will give you the number of rotations to make and then if you times it by 360 you should get the value to put into maya's rotational value.... user added image in theory anyways. So you need to calculate the distance you've travelled (which is easy enough using 2d vector math)

I hope this helps I can't test it out really but if you are near a library check out some basic math and physics books and they might tell you how to do it exactly.

Alan


Technical Director - Framestore

Currently working on: Your Highness

IMDB
# 4 15-11-2003 , 08:15 PM
Registered User
Join Date: Jun 2003
Posts: 8

Originally posted by NitroLiq
1. Check out some of the freebie video tutorials on set driven key (SDK). They might give you some ideas of having the car "drive" the rotation of the wheels (no pun intended).

2. Draw a cv curve from the top view and then select your car and the path. Go to animate>motion paths>attach to motion path. Your car should now animate along the path you drew.

Nitro, when you place the car in the animation path can you set the SDK's to trigger the rotation of the wheels when there is any movement of the car instead of in a specific direction?
for example, i want to have the car make a right angle turn...would i just have to do a new SDK for after the turn?? I hope that makes sense. Thanks for your help!!

# 5 15-11-2003 , 08:34 PM
NitroLiq's Avatar
Moderator
Join Date: Nov 2002
Location: New York
Posts: 2,133
The best way would probably be by writing an expression for the wheels as pure morning suggested. I did a quick search around and found something that may specifically help you with your wheel dilemma here.


"Terminat Bora Diem, Terminal Auctor opus."

Last edited by NitroLiq; 15-11-2003 at 09:19 PM.
# 6 20-11-2003 , 05:14 AM
Registered User
Join Date: Jun 2003
Posts: 8
That is all extremely helpfull, the only other thing that i can't figure out is that i would like my car to get hit and then travel sideways. I have it set to a motion path and if i rotate it at one point, it rotates for the whole thing. I also tried to tweak the shape to simulate car crash damage but it changed for the entire animation!! How do i get these to happen at specific times?? Sorry, I try to be as clear as possible but i just barely know what i am talking about. You can see how beginner i really am!! THANKS GUYS!!

~eric

# 7 20-11-2003 , 05:51 AM
NitroLiq's Avatar
Moderator
Join Date: Nov 2002
Location: New York
Posts: 2,133
Have you thought of setting up a couple different cameras? This way, you could render out your animation of the car on the motion path then, using the same scene without the motion path and a different camera do another animation by manually setting keys for the hit/slide. Then composite the whole thing in a compositing application.

You also might try creating several animations and layer them using the trax editor...bit more advanced though. I haven't really done much with it.


"Terminat Bora Diem, Terminal Auctor opus."
Posting Rules Forum Rules
You may not post new threads | You may not post replies | You may not post attachments | You may not edit your posts | BB code is On | Smilies are On | [IMG] code is On | HTML code is Off

Similar Threads