Whenever you want to make a sketch either complex or simple in 3D space, you can intersection tool. This become handy tool for making complex sketch out of simple sketches. The principle of working of this tool is simple but sometime tricky.
In intersection tool 2 sketches have to be drawn on different planes. These two sketches will act as the components for your final sketch. So you should know how your final 3D space sketch will look like in certain plane. For example an arc will look like a straight line in some plane or a cylinder will look like a rectangle in a plane and a circle in some other plane.
Let’s start the exercise then it will become clear.
Open creo parametric create a new part file by following the path
File > new > part
Select the front plane and click on sketch icon
Front-plane > sketch
In sketching window make an arc as look like in the figure. Dimensions are not critical and can be chosen accordingly.
After this select any other plane either top-plane or right-plane and again go into sketching window by clicking at sketch icon. In sketching windows make another arc.
After completing both sketch, just change the part view to see how both section have been placed this is optional.
Now select one sketch and intersection tool become active. Now click at the intersection tool.
This tool will ask to select the second sketch so now just select the second sketch. You can see change of states in the tool as shown in figure below.
After selecting the second sketch just click on the OK button to complete the intersection ( creation of single sketch by combining two other sketch on different planes). In the following figure you can see that final sketch (the arc with dark blue color) will look same in planes upon which we have drawn sketches earlier.