<HTML><BODY style="word-wrap: break-word; -khtml-nbsp-mode: space; -khtml-line-break: after-white-space; "><DIV>Hi Vadim,</DIV><DIV><BR class="khtml-block-placeholder"></DIV><DIV>If I understand you correctly, you would like to correlate the deformations you obtain from the FEM registration with the material properties of your registered objects. The forces that the FEM method is using to perform the registration derive from the derivatives of the available image metrics. These measurements have no relationship to the material properties of your registered objects. Therefore, trying to make biomechanical inferences from the chosen Lame constants would be incorrect. I believe Luis has explained this in previous postings. </DIV><DIV><BR class="khtml-block-placeholder"></DIV><DIV>The Crank-Nicolson solver is used for the FEM image registration filter which does utilize the rho and time step parameters. However, there are other solvers available for general FEM use.</DIV><DIV><BR class="khtml-block-placeholder"></DIV><DIV>Good luck,</DIV><DIV>Nick</DIV><DIV><BR class="khtml-block-placeholder"></DIV><DIV><BR class="khtml-block-placeholder"></DIV><DIV><BR class="khtml-block-placeholder"></DIV><BR><DIV><DIV>On Oct 30, 2006, at 10:01 PM, Vadim Stakhursky wrote:</DIV><BR class="Apple-interchange-newline"><BLOCKQUOTE type="cite"><SPAN class="Apple-style-span" style="border-collapse: separate; border-spacing: 0px 0px; color: rgb(0, 0, 0); font-family: Helvetica; font-size: 12px; font-style: normal; font-variant: normal; font-weight: normal; letter-spacing: normal; line-height: normal; text-align: auto; -khtml-text-decorations-in-effect: none; text-indent: 0px; -apple-text-size-adjust: auto; text-transform: none; orphans: 2; white-space: normal; widows: 2; word-spacing: 0px; "><DIV><FONT face="Arial" size="2"><SPAN class="Apple-style-span" style="font-family: Arial; font-size: 10px; ">Hello, Nick,</SPAN></FONT></DIV><DIV><FONT face="Arial" size="2"><SPAN class="Apple-style-span" style="font-family: Arial; font-size: 10px; ">Can you please point to the units of the parameters in the FEM routine? Pho, E, etc. g/cm^3? N/m^2? I am trying to apply the method to some biomed deformations, but without exact knowledge it's hard to interpret the result.</SPAN></FONT></DIV><DIV><FONT face="Arial" size="2"><SPAN class="Apple-style-span" style="font-family: Arial; font-size: 10px; "> Thanks a lot,</SPAN></FONT></DIV><DIV><FONT face="Arial" size="2"><SPAN class="Apple-style-span" style="font-family: Arial; font-size: 10px; "> Vadim</SPAN></FONT></DIV><DIV><FONT face="Arial" size="2"><SPAN class="Apple-style-span" style="font-family: Arial; font-size: 10px; ">P.S. Also, my understanding is the basic solver is static. Does it mean Rho and time step is not considered? Thanks!</SPAN></FONT> </DIV><BR class="Apple-interchange-newline"></SPAN></BLOCKQUOTE></DIV><BR></BODY></HTML>