Page Layout ⇒ strange big gap between two paragraphs

[neumannturing]

There is a big gap between two paragraphs(the gap is about 1 inch). This segment is in the middle of the whole paper. The spacing between all other paragraphs is fine. What is wrong?

Code: Select all

paragraph 1 bla bla bla
\begin{figure}[t]
\newlength{\modelsize}
  \modelsize = \linewidth
  \advance \modelsize -\columnsep
  \divide \modelsize 1
  \centering
  \includegraphics[scale=0.4]{picture file}
  \caption{bla bla bla}
  \label{fig:mciso}
\end{figure}

paragraph 2 bla bla bla.

[daleif]

full minimal example please.

BTW: what are that length calculation for?