The only way to decrease the intercolumn space is to increase the column width. You can do this manually, or you can define auxiliary lengths to do the calculations for you; in the following example, you simply set the desired value for \MyColSep
and the \MyColWd
will give you the column width producing the desired separation:
\documentclass{beamer}
\usepackage[orientation=landscape,size=a0,scale=1.4,debug]{beamerposter}
\usepackage{lipsum}
\usepackage{calc}
\beamertemplategridbackground[1cm]
\newlength\MyColSep
\setlength\MyColSep{1cm}
\newlength\MyColWd
\setlength\MyColWd{0.3333\textwidth-0.6666666\MyColSep}
\begin{document}
\begin{frame}[t]{}
\begin{columns}[t]
\begin{column}[t]{\MyColWd}
\lipsum[1-3]
\end{column}
\begin{column}[t]{\MyColWd}
\lipsum[1-3]
\end{column}
\begin{column}[t]{\MyColWd}
\lipsum[1-3]
\end{column}
\end{columns}
\end{frame}
\end{document}

To control the margins you can use \setbeamersize
,a and the onlytextwidth
option for the columns
environment:
\documentclass{beamer}
\usepackage[orientation=landscape,size=a0,scale=1.4,debug]{beamerposter}
\usepackage{lipsum}
\usepackage{calc}
\beamertemplategridbackground[1cm]
\setbeamersize{text margin left=3cm,text margin right=3cm}
\newlength\MyColSep
\setlength\MyColSep{1cm}
\newlength\MyColWd
\setlength\MyColWd{0.3333\textwidth-0.66666\MyColSep}
\begin{document}
\begin{frame}[t]{}
\begin{columns}[onlytextwidth]
\begin{column}[t]{\MyColWd}
\lipsum[1-3]
\end{column}
\begin{column}[t]{\MyColWd}
\lipsum[1-3]
\end{column}
\begin{column}[t]{\MyColWd}
\lipsum[1-3]
\end{column}
\end{columns}
\end{frame}
\end{document}
As far as I know, the only possibility is to interrupt the columns environment, include the wider material end then start a new columns environment (in fact, that's what the author of the poster you linked to does):
\documentclass{beamer}
\usepackage{lipsum}
\begin{document}
\begin{frame}
\begin{columns}[t,totalwidth=\textwidth]
\column{.5\linewidth}
Some material for the first column goes here
\column{.5\linewidth}
Some material for the second column goes here
\end{columns}
\vfill
\includegraphics[width=\textwidth,height=1cm]{cat}
\vfill
\begin{columns}[t,totalwidth=\textwidth]
\column{.5\linewidth}
Some material for the first column goes here
\column{.5\linewidth}
Some material for the second column goes here
\end{columns}
\end{frame}
\end{document}

And here's the code showing one possible approach to have an image spanning two out of three columns. The idea is to have one outer columns
environment of width, for example, \textwidth
; inside this environment two columns are created; one of them twice as wide as the other one; inside the wider column, the idea from the previous example is used: an inner columns
environment is used to produce two columns of equal width; this inner columns
environment is then ended to include the image spanning two columns, and finally another inner columns
environment is used to hold the final two columns.
\documentclass{beamer}
\usepackage{lipsum}
\begin{document}
\begin{frame}
\begin{columns}[t,totalwidth=\textwidth]
\column{.32\textwidth}
Some material for the first column goes here. Some material for the first column goes here.
Some material for the first column goes here. Some material for the first column goes here.
\hfill
\column{.65\textwidth}
\vspace*{-\baselineskip}
\begin{columns}[t,totalwidth=\textwidth]
\column{.48\textwidth}
Some material for the second column goes here.
\column{.48\textwidth}
Some material for the third column goes here.
\end{columns}
\includegraphics[width=\textwidth,height=2cm]{cat}
\begin{columns}[t,totalwidth=\textwidth]
\column{.48\textwidth}
Some material for the second column goes here.
\column{.48\textwidth}
Some material for the third column goes here.
\end{columns}
\end{columns}
\end{frame}
\end{document}

Best Answer
The
columns
environment internally usesminipage
, so you can simply useminipage
s in your document; a simple example (I added some frames just as visual guidelines). The\Colsep
length can be used to control the separation between theminipage
s:I used a fixed height (
6cm
) for the innerminipage
s and center alignment but this, of course, is optional.