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### Wanted: More sophisticated 3D car rig

Posted: 08/26/2016, 10:10 pm
I have a vehicle with multi-object wheels - tire on spoke rim, and wheel hub with visible brake pad. I would like to create a rig so that I can push the car and turn the steering and have the wheels rotate and turn properly. Is this possible? Does it already exist? I have not been able to find anything in my searches.

I realize that Andrew did a simple car rig tutorial, and that worked pretty well - except the wheel rotation was hand animated and the wheels were all just one piece. I am looking for a more sophisticated set up.

I am a rank beginner with expressions and math is NOT my friend. Can anyone help me with setting this up? All I have available to me is AE and the bundled C4D lite and E3D.

Thanks for any tips, suggestions, links, etc.

-Tom

### Re: Wanted: More sophisticated 3D car rig

Posted: 08/27/2016, 12:09 am
Aux channels and expressions is the way to go. It might be better to do this with a motion path null rather than steering wheel and speed controls. I could take a look at the task next week if no one else gets there first.

### Re: Wanted: More sophisticated 3D car rig

Posted: 08/27/2016, 8:00 am
Very cool! Thanks, star+circle, you've been really helpful to me previously.

### Re: Wanted: More sophisticated 3D car rig

Posted: 08/27/2016, 12:05 pm
Hello TGlinskas,

attached you find a basic AE-Project with a simple Car-Rig.

https://youtu.be/UopRVLQ-468

There are two Compositions, Comp1 and Comp2. They are nearly
the same, only in Comp2 i have linked the "car y rotation"
to the "front wheels y rotation" (with a multiplier 0.5), so
if you turn the front wheels, the car turns also.

of the wheels and the car to the right Positions !
Also for the Subfolders "front right" and "front left".

Hierarchy:

E3D
Group1 >> Car (all parts) >>AUX5
Subfolders:
>>(Subfolder)backwheels
>>back left >>AUX2
>>back right >>AUX2
>>(Subfolder)front right >>AUX3
>>front right >>AUX1
>>(Subfolder)front left >>AUX3
>>front left >>AUX1

Group2 >>Floor

AUX1 = front wheel rotation
AUX2 = back Wheel rotation
AUX3 = turns the front wheels (y-rotation)
AUX5 = y-rotation car

The movement of the car is transformed into the wheel rotation:

d = 100
c = -(2*Math.PI*d);
x = 360/c*Position value;

It's not easy to measure the diameter of the wheel, so i set
a initial value of 100. But this value is linked to a slider,
so you can modify or animate this (acceleration/deceleration),
don't set this value to 0 !

See my post here (animation diameter value):
viewtopic.php?f=42&t=127135#p383707

Should be only a basic idea. Have fun !

Hans

### Re: Wanted: More sophisticated 3D car rig

Posted: 08/29/2016, 8:11 am
Thanks, hans123. I will check that out!

EDIT:
Ok, I swapped out parts using parts from Motion Graphics 2 and after some tinkering and adjusting orientation, got it to work. Thank you very much! I will now try this setup with my car model and see if I can get it to drive across the parking lot and into a space.

I do have one question, can I have a part of the wheels that track and turn, but do not rotate?

-Tom

### Re: Wanted: More sophisticated 3D car rig

Posted: 08/29/2016, 3:52 pm
Hello TGlinskas,

you can use a "Checkbox" to stop the Expression (example wheel rotation) at a given point
and use instead of this another value.

I have explained this here:

viewtopic.php?f=4&t=124906&hilit=+stop+expression#p375782

for the front wheel rotation:

control =thisComp.layer("Null 1").effect("Checkbox Control")("Checkbox") ;

if (control == 1){
d = thisComp.layer("Null 1").effect("diameter front wheels")("Slider");
c = -(2*Math.PI*d);
x = 360/c*effect("Element")("1. Position XY")[0];;
}else{
[100];
}

If the Chechbox is ON, the wheels rotate with the car movement, if the Checkbox is OFF
the Wheels stay by 100° (you can use another value or link this to a Expression control).

If you want to separate the front wheels, you must use different AUX Channels for the left and right wheels.

Hans

### Re: Wanted: More sophisticated 3D car rig

Posted: 08/30/2016, 5:22 pm
I am having trouble getting the rig to work with a different model. The axis of rotation is off. I spent quite some time trying to make adjustments, but to no avail.

The model is too big to attach, so I am attaching a RAR file with the AE file and E3D file of the car as well as a link to the freebie download where I originally got it.

Hopefully these files and the link below will be enough for you to check them out.

http://tf3dm.com/3d-model/maserati-gt-86966.html