I wasn't sure if it were to be done via Data or Triggers, so I'm posting this here.

How do I make a unit drift when it turns, like a race car?
And is there a way to make this toggle-able on a unit?

The easiest way would be to just give the unit a ridiculous turn radius, but that wouldn't give the visual effect you probably want.

There's probably a good way to do it with the Data Editor, but I'm more of a Trigger Editor guy. My general suggestion for the trigger approach would be to reduce the unit's speed and have a micro periodic event (every 0.05 seconds of the game) activated while the unit is moving. Record the facing direction of the unit, and then after a small delay (depending on how long you want the drift to happen, maybe 1 second) move the unit in that direction by a minuscule amount (the fact that this trigger runs so often will create a sliding effect). The only problem is you'll probably get weird results for people who spam different directions, but tuning the times can vary this effect. This would take care of things like trying to suddenly stop, though, and you'll have a neat effect where it takes some time to accelerate to full speed from a stationary position.

The other approach with triggers would be to detect a significant change in direction while the unit is moving. You can detect the event that the unit is issued an order, and then compare the angle from that unit to the new order to the angle of the unit's current facing direction, and if the change is significant enough, make a loop that slides the unit for however long you want the slide to last.

The only slightly annoying thing is figuring out when the unit is currently moving or not. The best you can do (to my knowledge) is to use the "Unit Is Issued Order" and "Unit Becomes Idle" events and keep track with a global variable.

This is definitely not working.
The problem is that ordering the unit replaces the order, so it'll get in the way of the gameplay a lot. If the player wants to cast an ability while this thing runs, there is a chance the ability won't be cast. And if I don't set it to "Replace Existing Orders", a player that spams order will never be affected by the drifting effect (and all players, in this context, will be spamming orders).
As it is, it just makes the movement of my Probe racer unit all clunky.
I also haven't bothered with making an "Is Moving" detection trigger since all the racers will basically be moving all the time (though I would add this safe-proof later on, but for testing, I don't think it was necessary).

As an ode to SC1 I'll remind you that "Move Unit" and "Order Unit" are two completely different actions.

Also, you need to store the facing angle of the picked unit into a variable before you do your wait; otherwise it will just get the direction they've been moving toward.

I don't have time to look through what else may be wrong with the trigger, but I'd work on those two issues first. Also, a distance of 1.1 is probably going to be too large a distance.

I would move it with blend & calculate a speed and a max facing change of the direction you are pushed into.

Ah! That makes more sense.

Sorry for not following, but I'm not sure I understand what is the purpose of calculating the max facing change.

Current trigger:

I've tried tweaking the numbers, but I just can't get the effect I want. I see the unit drifting slightly, but it's nothing ever near what I am expecting. I want a big sliding effect with decently high speed unit.
I wasn't sure about adding that "Position" variable, but it seemed to increase the sliding effect as long as certain parameters' values were kept within a certain range.
It seems like the solution could be to increase the Move value, but restrict it to when the players are not moving precisely forward, and thus to increase its value based on the Turn Angle compared to the last Forward Angle?

I quickly wrote up a little something that should be easy to use:

And a simpler action definition to call it:

Here's an example of using these new action definitions:

That complicated If/Then condition is just me being bad at math - all it's doing is checking to see that the angle change is greater than 40 degrees.

Basically, you can just call Slide Unit and give it the unit and its facing angle and it will automatically drift (distance and duration based on its speed), or if you want to fine tune it more, you can call the Drift Unit action instead and specify a distance over a period of time.

Note that without checking to see if the unit is already drifting, you can get interesting results by spamming different directions in rapid succession. But I'll leave that up to you on how you want to handle that (if at all).

Attached is the test map I made. You can just copy pastarino the Drift/Slide actions into your own map, and then use them like you would any other trigger action.

Attachments:

I ended up using a friend's work:


Along with:


Works wonders.

Thanks for you work anyways, though.