GameMaker Changing Physical Position VS Changing Regular Postion? (SOLVED)

[Fixer90]

So I've got an object to be moved around via inputs, and this object has physics on and a physics-collision circle as well; it moves based on 2 variables: xspeed and yspeed. How these 2 variables are determined is not important - what is important is this:

x += xspeed;
y += yspeed;

phy_position_x += xspeed;
phy_position_y += yspeed;

What's the difference between these two? How will my object act one way in comparison to another way?

 

[Bayesian]

If I understand correctly when an object has physics enabled x and y are basically read only. You can change them but this won't move the object and will de-sync x and y from phy_position_

 

[Jezla]

If you're going to move your instances in this fashion, you're better off not using physics. As @Bayesian said, x and y are read-only with physics turned on, and manipulation them (or the physics position) directly breaks the simulation. If you're going to move an instance using physics, apply a force or an impulse instead.