In the SIGGRAPH 94 version of our paper, there was an error in equation (9)
that has been corrected in the Postscript file available via WWW in
this directory.
In SIGGRAPH 94, equation (9) said:
The repulsion force and desired velocity is again proportional to
the gradient of energy with respect to position:
\begin{equation}
\Pi =
-(\sigma^i)^2 E^i_{\p^i} =
(\sigma^i)^2 \sum_{j=1}^n \Bigl(
{\rij \over (\sigma^i)^2} E^{ij}
-{\rij \over (\sigma^j)^2} E^{ji}
\Bigr)
\end{equation}
The subtraction should be an addition.
The correct equation is:
The repulsion force and desired velocity is again proportional to
the gradient of energy with respect to position:
\begin{equation}
\Pi =
-(\sigma^i)^2 E^i_{\p^i} =
(\sigma^i)^2 \sum_{j=1}^n \Bigl(
{\rij \over (\sigma^i)^2} E^{ij}
+{\rij \over (\sigma^j)^2} E^{ji}
\Bigr)
\end{equation}
-Paul Heckbert, 23 Jan. 95