Front Wheel Control
If you don't need to control the turning of the front wheels right and left and only want the wheels to spin (like on a skateboard) then skip to section 3
1) If you have multipole cars in the animation, it would be a very good idea to rename all your surfaces with the surface name and then the name of the car or something similar.
2) Now go to each wheel layer and move them into their appropriate positions. If you followed the way I ordered everything, put layer 2 in the front left wheel well, layer 3 in the front right wheel well, layer 4 in the rear right wheel well, and layer 5 in the rear left wheel well. Make sure all the wheels are alighed. you can also make the wheels high up in the wheel well so the car looks lowered.
3) Next, on the "items" tab go to "add," "object" and "add Null" name it like this: NAME OF CAR_front_rotation Mine looks like this eg6_front_rotation Now press OK and place it infront of the car's front valence.
4) Add another Null object and name it like this: NAME OF CAR_front_rotation_balancer Mine looks like this: eg6_front_rotation_balancer Place it in front of the front valence and just in front of the other Null object.
5) Now go to layer 2 and on the "items" tab click on "motion options" (or press M on the keyboard) and parent layer 2 to layer 1 (which should be the body of the car). Do the same for layers 3,4,5 and your 2 Null objects.
6) This is very confusing so please refer to the thumbnail pictures below for help. Now it's time to put in the expressions. Go to the graph editor and click on the "Expressions" tab to the right and click "New" Name is "NAME OF CAR follow front" (for me, EG-6 Follow Front) and set the value to " value+([NAME OF CAR_front_rotation.Rotation.H/2) "(do not put the quotations in) mine is Value+([eg6_front_rotation.Rotation.H]/2) Now, in the channels window at the top, highlight all the channels in there and clear them by pressing SHIFT+D. Next, click on the channels tab at the bottom and expand layer 1 and drag and drop the Rotation H channel into the channel window at the top. Highlight it and on the expressions tab to the right and click apply.
7) On the "expressions" tab click new and anme it "NAME OF CAR Front Wheels Turn", mine is "EG-6_Front_WHeels_Turn" In the top channels window, clear everything. Now drag and drop your front wheel Rotation H channels into the top channel window. For me, it was layer 2 and layer 3. The Expression is [NAME OF CAR_front_rotation.Rotation.H]-[NAME OF CAR_front_rotation_balancer.Rotation.H] mine is [eg6_front_rotation.Rotation.H]-[eg6_front_rotation_balancer.Rotation.H] now highlight the 2 channels and click apply.
That's it for section 2. These expressions allow you to control the front wheel directions. To control it, go to your front rotation balancer Null object and rotate it on the H direction. It is an inverse relationship so when you move the mouse right the wheels will turn left and the opposite is true. On to section 3.
On to section 3.
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