Circular motion is a constant topic in the forums, so, I decided to put together a simple and direct tutorial covering the basics.
Here's what we're going to achieve.
See the attached .capx file.
First things first, there are some basic elements of circles that you'll need to understand.
Diameter (D): the length of a line whose endpoints lie on the circle and which passes through its center.
Radius (R): the length a line which joins the center of the circle to any point on the circle itself. It measures half the Diameter.
Pi (π): a mathematical constant. There's a System Expression in Construct 2, called pi (isn't that awesome?), for that.
Circumference (C): the length of one circuit along the circle. It measures the diameter times Pi (D x π or 2 x π x R).
In order to achieve the desired effect, we need to move the avatar, represented in our tutorial by the cute little moons and the devil moon, in a way that the distance to a fixed point (the Radius) is constant, thus, making a circular pathway.
Here's how we control the Radius! There are two main elements that will affect the radius of the pathway in circular motion:
Speed (spd): the amount of pixels the avatar moves in a tick. The higher the Speed, the longer the Radius.
Rotation (rot): the amount of degrees the avatar rotates in a tick. The higher the Rotation the shorter the Radius.