How to make the graph edges in TikZ trees rounded? (preserving the clean syntax)

rounded-cornerstikz-pgftikz-trees

I am a beginner in TikZ and I tried to search for a solution to the best of my ability, but it's just too obscure of a topic to have a proper answer yet. To start off, this is my code:

\begin{tikzpicture}[
    every node/.style = {draw, circle, minimum size = 1cm},
    grow via three points = {one child at (1.25,1.25) and two children at (1.25,1.25) and (2.5,1.25)},
    edge from parent path = {(\tikzparentnode.east) -| (\tikzchildnode.south)}
]
\node{}
child {
    node{}
    child{node{}}
    child{node{}}
    child{node{}}
}
child[missing]{}
child[missing]{}
child[missing]{}
child {
    node{}
    child {
        node{}
        child {node{}}
    }
    child[missing]{}
    child{node{}}
};
\end{tikzpicture}

Here's how it looks like when rendered:

enter image description here

This code was originally more complicated, with lots of repetitive commands, but I managed to simplify it using this convenient child/node syntax. I also tried looking into the forest package, but it didn't seem to allow for these kinds of trees. Anyways, my issue is that the edges have very sharp turns, and I would like to make them more rounded. The following post seems to contain the solution I am seeking, but it didn't work when I tried it: Round corners in connections between nodes

(That is, I tried adding every edge/.style = {draw, rounded corners = 0.5cm},, but it didn't seem to do anything.)

So this is where I am stuck now. I do not want to use any other kind of syntax (more complicated than the node/child one), considering how many of these images I ultimately want to create. The more I can simplify and automate the actual code, the better. I also do not want to rotate or reflect the tree in any way for the sake of migrating over to a different solution (i.e. forests), it must grow from the bottom left and upward. And once more, just to be absolutely clear about what I intend to achieve, here's an illustration, rendered using draw.io:

enter image description here

Thanks for any answers.

Best Answer

Add the rounded corners option to edge from parent path.

edge from parent path = {[rounded corners=3mm](\tikzparentnode.east) -| (\tikzchildnode.south)}

enter image description here

\documentclass{article}
\usepackage{tikz}
\usetikzlibrary{trees}
\begin{document}

\begin{tikzpicture}[
    every node/.style = {draw, circle, minimum size = 1cm},
    grow via three points = {one child at (1.25,1.25) and two children at (1.25,1.25) and (2.5,1.25)},
    edge from parent path = {[rounded corners=3mm](\tikzparentnode.east) -| (\tikzchildnode.south)},
]
\node{}
child {
    node{}
    child{node{}}
    child{node{}}
    child{node{}}
}
child[missing]{}
child[missing]{}
child[missing]{}
child {
    node{}
    child {
        node{}
        child {node{}}
    }
    child[missing]{}
    child{node{}}
};
\end{tikzpicture}

\end{document}
Related Question