This is a post that was created 2 years ago talking about creating bounding boxes with cornered edges, and the answer was posted:
Sorry, no there is currently no way of doing that. In most cases you can use a masking image though, like in our pin demo: http://fancyproductdesigner.com/product/bagde-pin/
Can anyone explain how I can do this? Is there still a requirement to do this or is the feature added?
No, bounding boxes can still only be rectangles. There is one new feature called masking, which allows using a .svg file as mask for a whole view (product builder, edit mask button directly above the product preview) or the old masking image trick.
This does not explain how to do it.
I also need to do a circle bounding box. I would gladly use the image trick, but what is this image trick
There are two ways to achieve this:
1. Using a svg mask
2. Using an overlay image as mask