I'm working on a new learning model and I needed a vector graphics tool to help me produce a visual representation of the model. I came across
Inkscape, with which I'm quite impressed. It's an open source product that strives to capture some of the functionality of Illustrator, Corel Draw, and Visio. It appears to do most of what I need. One of the great things I realized while playing with Inkscape was the ability to pull a vector image in from the Microsoft Clipart library and edit it in Inkscape. Just copying from PowerPoint won't bring over the vectors; instead, you must copy the item from the clipart library, as shown here.
Then, just Paste in Inkscape and the individual vector pieces are placed. The image below shows where I've updated an avatar with a better wardrobe and hair style. I also changed his eye color and moved the corners of his mouth down in protest. '-)
Inkscape produces SVG graphics, so the edited images looked nice and clean in Inkscape; I just did a copy and paste back into PowerPoint to illustrate the changes. Here are a couple of samples in Inkscape. Context menus provide you plenty of options, including the ability to ungroup grouped vectors:
Below, you can see that vectors come through quite well and can easily be modified.
Again, for my needs, it's a pretty robust tool...and certainly worth investigating.
Have fun! Joe