How does Beamer's incremental specification work?

Question

I am trying to animate as follows:

1. Slide 1 should show only Bullet 1
2. Slide 2 should add root and child1
3. Slide 3 should add child2
4. Slide 4 should add Bullet 2

Thanks in advance.

\documentclass{beamer}
\mode<presentation>{\usetheme{Madrid}}


\usepackage[utf8]{inputenc}
\usepackage{tikz}
\usetikzlibrary{shapes.geometric, arrows}

%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
\tikzstyle{process} = [rectangle, minimum width=3cm, minimum height=1cm, text centered, text width=3cm, draw=black, fill=orange!30]
\tikzstyle{arrow} = [thick,->,>=stealth]

%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
\begin{document}
\begin{frame}

\begin{itemize}[<+->]
\item Bullet 1

\begin{tikzpicture}[node distance=3cm]

\node (root) [process] {root};
\node (child1) [process, below of=root, xshift=-4cm] {child1};
\draw [arrow] (root.south) -- (child1.north);


\node<+(1)-> (child2) [process, below of=root, xshift=4cm] {child2};
\draw<.(1)-> [arrow] (root.south) -- (child2.north);


\end{tikzpicture}

\item Bullet 2
\end{itemize}
\end{frame}

\end{document}

Answer 1

Update 2 :Some explanations on incremental overlays specifications

The specifics of overlays can be absolute or relative.

When they are absolute:

we put the slide number as <3> which means that this command will be visible on slide #3.

When they are relative:

the value of the counter beamerpauses is represented by the + symbol (Please note the + sign is not an addition).

So if the slide is number 3 and an order:

• specifies <+->, then this is expanded to <3->;
• specifies <+(1)->, then this is expanded to <4->;
• specifies <+(-1)-+>, then this is expanded to <2-3>;

The other symbol to understand is the dot symbol . When presented in an overlay specification, it represents the previous value of the counter.

So if the slide is number 3 and an order:

• specifies <.->, then this is expanded to <2->;
• specifies <.(1)->, then this is expanded to <3->;
• specifies <.(-1)-.>, then this is expanded to <1-2>;

Update 1: With Incremental Specifications

\begin{document}
\begin{frame}

\begin{itemize}%[<+->]
\item<1-> Bullet 1

\begin{tikzpicture}[node distance=3cm]

\node<+(1)-> (root) [process] {root};
\node<.(1)-> (child1) [process, below of=root, xshift=-4cm] {child1};
\draw<.(1)-> [arrow] (root.south) -- (child1.north);


\node<+(1)-> (child2) [process, below of=root, xshift=4cm] {child2};
\draw<.(1)-> [arrow] (root.south) -- (child2.north);


\end{tikzpicture}

\item<+(1)-> Bullet 2
\end{itemize}
\end{frame}

\end{document}

---

Old answer: With overlay specifications

\documentclass{beamer}
\mode<presentation>{\usetheme{Madrid}}


\usepackage[utf8]{inputenc}
\usepackage{tikz}
\usetikzlibrary{shapes.geometric, arrows}

%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
\tikzstyle{process} = [rectangle, minimum width=3cm, minimum height=1cm, text centered, text width=3cm, draw=black, fill=orange!30]
\tikzstyle{arrow} = [thick,->,>=stealth]

%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
\begin{document}
\begin{frame}

\begin{itemize}[<+->]
\item Bullet 1

\begin{tikzpicture}[node distance=3cm]

\node<2-> (root) [process] {root};
\node<2-> (child1) [process, below of=root, xshift=-4cm] {child1};
\draw<2-> [arrow] (root.south) -- (child1.north);


\node<+(1)-> (child2) [process, below of=root, xshift=4cm] {child2};
\draw<.(1)-> [arrow] (root.south) -- (child2.north);


\end{tikzpicture}

\item<4-> Bullet 2
\end{itemize}
\end{frame}

\end{document}