Yes, snapping is very complex in Inkscape. I'd guess it took me a couple of years, before I felt like I had a solid understanding. Although part of the reason it took so long is because I didn't ask questions right away, and as long as I found other ways to achieve something, I didn't need to ask. But anyway, continuning with your questions...
After you draw a rectangle, with Rectangle tool
, you need to do Object menu > Object to Path. Then when you switch to the Node tool
, you will see the nodes.
Actually, I think the corners of the rectangle might snap together.... Hah -- yes, they do!
Generally with snapping (and especially for newbies) it's best Not to have all the options enabled at the same time. Sometimes newbies get desperate and have them all enabled. But really what that does, is allow every snappable element to try to snap to every available target. It's kind of a crazy and unmanagable situation.
So attached is a screenshot of snap settings which I find to be useful for most situations. I leave mine like that, and when I need something different, I just change whatever I specifically need. And when I'm finished, I change them back. I've noticed a lot of newbies seems to use the bounding box options for snapping, but I find it limiting. Only rarely do I find a situation where I have to use snapping to a bounding box.
I also find it very helpful to use Inkscape Preferences > Behavior > Snapping > Only snap the node closest to the pointer. Then when I'm dragging something to snap it to something else, I grab the object with the mouse close to that node. I find it helps to prevent accidentally snapping the wrong thing to the wrong target. Although, since Inkscape added the snap indicator (the small text which pops up when the snap happens) I guess it's not as important as before that. Maybe it's just a habit now?
1) Can they be edited after the fact? For example, each part seems to be a unique element (the vertical and then the angles).
I'm not sure what you've found or what you mean. After what fact?
I think you might have found the Pencil tool, where you click once to start a path, and click once to end a path. However, the Pencil tool is primarily a freehand drawing tool. So you press the mouse and keep it pressed while you drag it around. Inkscape automatically creates and places the nodes for you.
The Pen/Bezier is the main path-drawing tool. With that, you click once to start, and every time you click after that, you place another node. Then you double-click (or press Enter, if you like key shortcuts) to end the path.
You might want to look at a tutorial I wrote some time ago. It's very long, but it's written in a way that you can find the section you need, and only read that. Plus, after you read a little bit of it, the rest becomes more and more predictable. Plus, it takes 10 or 20 times longer to read, than to actually perform the steps. It covers all the path tools.
https://forum.inkscapecommunity.com/index.php?action=articles;sa=view;article=72) I drew two verticals and found that they didn't line up on a grid as expected and even though I had two path lines of the same thickness, I couldn't get them to line up on top of each other perfectly.
If you hold the Ctrl key while you draw, it will constrain the tool to vertical or horizontal, or also to 15° angles, if you move the mouse too far out.
Or if you have snapping enabled at the same time the grid is enabled, the Pen or Pencil tool will snap the nodes to the grid intersections.
3) They seem to be all stroke. If I draw a "line" with one and fill it, it fills to the right empty space. Perfect would be a line with a center file and a stroke around the entire path as a border. I can't get that to go at all unless I'm not supposed to be making this shape with just one "line".
You can make a rectangle in just one line, using the Pen tool. (Now I'm pretty sure you discovered the Pencil tool.) Click once to start, click once again at the next 2 corners of the rectangle (using Ctrl to keep straight) (or use a grid). When you come back around to start, click once inside the tiny box, to end. If the mouse isn't exactly inside the box, the path will look like it's closed, but it won't be closed. The tiny box will become red, when your mouse is in the right place.
Technically, what you draw with the Pen or Pencil tools, are stroked paths. Technically, paths are invisible. If the path has no stroke, you won't be able to see it, even though it will exist. If it's selected, and you have the Node tool enabled, you will be able to see the nodes, but you won't see the path. Since that would make it nearly impossible to get much work done, Inkscape makes paths that are automatically stroked when you draw them with Pen or Pencil tools.
You can fill a path whether it's open or closed. But if it's an open path, the fill will only show when the path has a shape which acts like a container. Attached is an example of what I mean. Maybe it would be better to say that it will only fill the concave portions. Most of the time, you'll want to make sure paths are closed, to give them a fill. (The Paint Bucket tool
allows to fill spaces which are entirely enclosed, but not by a single path -- a whole different way to give color.)
4) How do I get the 45-degree part of the line to be of a reliable length? I draw one of these shapes and simply cannot replicate it (as I need them with different heights, but all with identical angled pieces).
It's better to draw the path the right length first, and then rotate it after. If you are doing a lot of this.... If the angled piece is always the same length, you can draw one, and just keep it outside the page border. Then whenever you need one, just duplicate that one, and move it into place. (Duplicated objects are right on top of the original - there's no obvious clue about it, so you just need to know it's there, and move it wherever you need it.) If it's in a different file, you can copy it out of one file and paste into another.
Or, you could draw the whole object - the vertical line with the 2 pieces attached already. Then when you need another one, duplicate it, scale it to the size you need, and move it into place. If you have a series of different sizes, which are always needed at the same sizes -- same routine -- make one set, and just duplicate it as needed.
If you make a whole shape or a whole series, I would suggest joining all the pieces together. Using the Node tool, drag a tiny selection box around 2 overlapping nodes. (If you use snapping, the nodes will be exactly overlapping.) Then either click this button on the Node tool control bar
, or use the key shortcut (whatever it is, I always use the button - look in Help menu > Key and Mouse Ref, to find the shortcut).
