A shape builder tool is a fonction that is in adobe illustrator and is the most usefull tools that i know in but corel vector don't have it.
You can combine multiple shapes to make a more complex shape using the Shape Builder Tool. Let’s see a simple example of how to create a cloud shape.
Step 1: Use the Ellipse Tool to create four to five circles (however you like to make a cloud). The bottom two circles should align.
Step 2: Use the line tool to draw a line. Make sure the line is perfectly intersecting with the bottom two circles.
Step 3: Select the Shape Builder tool in the toolbar.
Step 4: Click and draw through the shapes you want to combine. an shadow area shows the area you combine.
example with images at the methode two of the site :