Animating a Car on a Path in 3ds Max - Part 03 - Turning the Wheels

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Industry
  • Design Visualization
Subject
  • Animation
  • 2015
Products
  • 3ds Max
Skill Level
  • Intermediate
Duration
9 min

Animating a Car on a Path in 3ds Max - Part 03 - Turning the Wheels

In this tutorial, you establish the relationship between the car’s front wheels and the steering wheel, so that the front wheel’s turn when the steering wheel rotates.

Notes
  • Recorded in: 3ds Max 2015
  • This tutorial is intended for use with 3ds Max version 2015 or higher.

Transcript

00:00:06 --> 00:00:13
Now that you have the car wheels spinning properly based on car travel, the next step is to control the turning of the front wheels.

00:00:14 --> 00:00:20
What I call Turning in this case is a rotation you apply to the front wheels as the car steers left or right.

00:00:21 --> 00:00:28
Here you will establish a link between the turning of the front wheels and the rotation of the steering wheel.

00:00:28 --> 00:00:36
This way, you'll be able to keyframe the rotation of the steering wheel and the front wheels will react to that change.

00:00:36 --> 00:00:44
Continue working on your file. You can also use the file named Car-Rig_wheel-turn.max if you need to catch up.

00:00:44 --> 00:00:51
Select the steering wheel and set your rotation mode to Local.

00:00:53 --> 00:01:04
As the steering wheel rotates on its local Z-axis, you want the front wheel helpers to also pivot on their local Z-axis.

00:01:04 --> 00:01:09
Make sure the steering wheel is selected and right-click to access the Quad menu.

00:01:10 --> 00:01:18
Choose Wire Parameters > Transform > Rotation > Zero Euler XYZ > Z Rotation.

00:01:19 --> 00:01:23
With the rubber band appearing, the next step is to select the Front Left wheel helper.

00:01:23 --> 00:01:29
As mentioned in the last movie, it's easy to make a mistake and pick the wrong object instead.

00:01:29 --> 00:01:37
Rather than risk that, use the H key or the Scene Explorer to select the Car_hlp_FL helper object.

00:01:37 --> 00:01:45
Wire the steering wheel to the helper's Transform > Rotation > Zero Euler XYZ > Z Rotation

00:01:46 --> 00:01:52
In the Wiring dialog, set the direction so that the steering wheel controls the helper,

00:01:54 --> 00:01:56
and click Connect.

00:01:57 --> 00:02:06
Do not dismiss the dialog just yet. Make sure the steering wheel is selected and test out the results by rotating it locally on its Z-axis.

00:02:06 --> 00:02:09
Not bad but the rotation is inverted.

00:02:10 --> 00:02:14
Place a - (minus) sign in front of the formula and update it.

00:02:16 --> 00:02:17
Try it again…

00:02:18 --> 00:02:22
Much better but you still need to fine-tune it.

00:02:22 --> 00:02:29
Usually, a steering wheel lock-to-lock range as it is called is far superior to that of a turning wheel.

00:02:30 --> 00:02:38
The front wheels on an average car may turn to about 45 degrees left or right giving them a range of about 90 degrees.

00:02:38 --> 00:02:45
A steering wheel however typically has about 3.5 revolutions, from left lock to right lock.

00:02:45 --> 00:02:53
In fact, the ratio between steering wheel and front wheel rotations is often about 14:1 on a regular car.

00:02:54 --> 00:02:57
Sports car may have a smaller ratio, maybe 9:1 or 10:1.

00:02:58 --> 00:03:04
It's even smaller on race cars. A Formula 1 car for example is probably closer to a 3:1 ratio.

00:03:05 --> 00:03:11
On your average every-day car, especially one built in the sixties, the ratio is around 14:1

00:03:11 --> 00:03:16
Therefore, divide the formula by 14 and update it again.

00:03:18 --> 00:03:23
Test the results; they should be quite a bit more natural this time around.

00:03:28 --> 00:03:31
Copy the formula using Ctrl+C,

00:03:36 --> 00:03:40
and repeat the procedure for the right wheel helper.

00:04:02 --> 00:04:05
Dismiss all wiring dialogs when done.

00:04:06 --> 00:04:12
With the car animated to travel along the path, you will now animate the steering wheel based on the path curves.

00:04:13 --> 00:04:17
Select the steering wheel and make sure you are in Local Rotate mode.

00:04:17 --> 00:04:25
Also, switch back your Time Display to Frames only, to ensure keyframes do not fall into the subdivisions.

00:04:26 --> 00:04:30
Enable Auto Key and take a global look at the animation.

00:04:31 --> 00:04:36
For the first 10 frames or so, the car is practically moving in a straight line.

00:04:37 --> 00:04:39
Go to Frame 10,

00:04:40 --> 00:04:42
and right-click the Time Slider bar.

00:04:43 --> 00:04:49
In the Create Key dialog, make sure only Rotation is enabled and click OK.

00:04:49 --> 00:04:55
This creates a rotation key at frame 10 ensuring no rotational changes happen before that frame.

00:04:56 --> 00:05:01
Now scrub the animation until the car is in the middle of the first turn.

00:05:02 --> 00:05:05
Frame 52 looks about right.

00:05:06 --> 00:05:15
Zoom in for a better view and rotate the steering wheel on its local Z-Axis until the front wheels are aligned with the turn.

00:05:26 --> 00:05:33
Zoom back again and scrub the animation until the car is in the middle of the second turn.

00:05:34 --> 00:05:37
Frame 112 looks good.

00:05:38 --> 00:05:43
Zoom in again and rotate the steering wheel the other way,

00:05:47 --> 00:05:50
until the front wheels look properly aligned.

00:05:58 --> 00:06:03
Finally go to the frame where you feel the wheel should be straight again,

00:06:08 --> 00:06:11
frame 140 seems like a good fit.

00:06:12 --> 00:06:16
Here you need to bring back the steering wheel to its original position.

00:06:16 --> 00:06:23
Although we didn't take note of the rotation values we established a second ago, there is an easy way to reverse them.

00:06:23 --> 00:06:30
One way is to copy the keyframe at frame 10 which represents the steering wheel at the original 0 angle.

00:06:31 --> 00:06:37
This can be done by holding the Shift key and moving the keyframe from 10 to 140.

00:06:41 --> 00:06:46
Another easier way comes courtesy of freezing the transforms earlier in the tutorial.

00:06:47 --> 00:06:54
Because of that, you can use Alt with a right-click and then choose Rotation to Zero.

00:06:54 --> 00:07:01
This realigns the steering wheel to its original state and creates a keyframe since Auto Key is enabled.

00:07:06 --> 00:07:08
Exit Auto Key when done.

00:07:10 --> 00:07:12
Adjust your view,

00:07:15 --> 00:07:18
and scrub the animation to test the results.

00:07:24 --> 00:07:31
At this point, you may want to reset the Time Display to Frames and Ticks to smooth the viewport playback.

00:07:36 --> 00:07:40
The animation is getting better but you can improve on it still.

00:07:41 --> 00:07:46
A heavy car from the sixties tends to have a lot of body roll when taking a turn.

00:07:46 --> 00:07:50
You need to establish a link between the body rotation and the steering wheel.

00:07:51 --> 00:07:57
This way, every time the car makes a turn, the body will lean a bit towards the outside of the turn.

00:07:58 --> 00:08:00
This is what you do in the next movie.
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Tags
  • 3ds Max
  • Animation
  • 2015
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