If you have a 3D deer in your yard....here's something I do with my son, every year...
Go out and take an arrow....and place it entering the deer at varying angles. Then I ask him what that arrow is going to take out (on that angle) as it passes through the animal. It's a great lesson on deer anatomy. I want my arrow to do the most damage to the internal vitals as it can (on a particular angle). We all do. Common sense. A sever qtring angle (though not "ideal" may not even have the arrow entering in the "kill zone". What's important is......the "kill zone" shifts, as angles are introduced. Entering behind the ribs is a great shot on a hard qtring away animal. Would I take this shot from 10yds? Yeah. 20yds? Not ME. Treestand height also plays a BIG role in shot placement. Again.....just think about the path of the arrow all the way through your target.
Here's a ggod anatomical representation of a whitetail deer....
Here's an example of an entrance hole on a qtring away doe...shot from 18' up.....
Same doe....and the exit hole....
Good luck.