<HTML><BODY style="word-wrap: break-word; -khtml-nbsp-mode: space; -khtml-line-break: after-white-space; "><DIV><DIV>On Aug 10, 2007, at 4:04 PM, Elaine Meng wrote:</DIV><BR class="Apple-interchange-newline"><BLOCKQUOTE type="cite"><P style="margin: 0.0px 0.0px 0.0px 0.0px"><FONT face="Monaco" size="4" style="font: 14.0px Monaco">To manually position a structure relative to another, you could<SPAN class="Apple-converted-space"> </SPAN></FONT></P> <P style="margin: 0.0px 0.0px 0.0px 0.0px"><FONT face="Monaco" size="4" style="font: 14.0px Monaco">interactively rotate/translate and/or use the "move" (translation) and<SPAN class="Apple-converted-space"> </SPAN></FONT></P> <P style="margin: 0.0px 0.0px 0.0px 0.0px"><FONT face="Monaco" size="4" style="font: 14.0px Monaco">"turn" (rotation) commands.<SPAN class="Apple-converted-space"> </SPAN>You can freeze/unfreeze a copy using the<SPAN class="Apple-converted-space"> </SPAN></FONT></P> <P style="margin: 0.0px 0.0px 0.0px 0.0px"><FONT face="Monaco" size="4" style="font: 14.0px Monaco">Active checkbox in the Model Panel (in the Favorites menu by default),<SPAN class="Apple-converted-space"> </SPAN></FONT></P> <P style="margin: 0.0px 0.0px 0.0px 0.0px"><FONT face="Monaco" size="4" style="font: 14.0px Monaco">the command "select," or the little checkboxes under the Command Line<SPAN class="Apple-converted-space"> </SPAN></FONT></P> <P style="margin: 0.0px 0.0px 0.0px 0.0px"><FONT face="Monaco" size="4" style="font: 14.0px Monaco">(also under Favorites).</FONT></P> <P style="margin: 0.0px 0.0px 0.0px 0.0px; font: 14.0px Monaco; min-height: 19.0px"><BR></P> <P style="margin: 0.0px 0.0px 0.0px 0.0px"><FONT face="Monaco" size="4" style="font: 14.0px Monaco">If you did manage to position copy 2 relative to copy 1 to your liking,<SPAN class="Apple-converted-space"> </SPAN></FONT></P> <P style="margin: 0.0px 0.0px 0.0px 0.0px"><FONT face="Monaco" size="4" style="font: 14.0px Monaco">you could write the transformation matrices out (see "matrixget"<SPAN class="Apple-converted-space"> </SPAN></FONT></P> <P style="margin: 0.0px 0.0px 0.0px 0.0px"><FONT face="Monaco" size="4" style="font: 14.0px Monaco">command).<SPAN class="Apple-converted-space"> </SPAN>From those you could calculate the transformation of 2<SPAN class="Apple-converted-space"> </SPAN></FONT></P> <P style="margin: 0.0px 0.0px 0.0px 0.0px"><FONT face="Monaco" size="4" style="font: 14.0px Monaco">relative to 1 and also generate appropriate matrices that would then<SPAN class="Apple-converted-space"> </SPAN></FONT></P> <P style="margin: 0.0px 0.0px 0.0px 0.0px"><FONT face="Monaco" size="4" style="font: 14.0px Monaco">position 3, 4, ... correctly (see "matrixset" command).<SPAN class="Apple-converted-space"> </SPAN>I admit I<SPAN class="Apple-converted-space"> </SPAN></FONT></P> <P style="margin: 0.0px 0.0px 0.0px 0.0px"><FONT face="Monaco" size="4" style="font: 14.0px Monaco">don't know how to do those calculations.<SPAN class="Apple-converted-space"> </SPAN>Anyone?</FONT></P> </BLOCKQUOTE><BR></DIV><DIV>It's a little tricky. Basically, you want to get copy 1's matrix to be the identity matrix while keeping copy 2 in the same relative position. Here's one way to do it (and maybe someone can suggest something better):</DIV><DIV><BR class="khtml-block-placeholder"></DIV><DIV>1) open yet another copy (copy 3) as a reference</DIV><DIV>2) use "matrixset" to set copy 3's matrix to be the identity matrix</DIV><DIV>3) use the "match" command with the 'active' keyword to match copy 1 onto the reference (copy 3) while also moving copy 2 appropriately</DIV>4) use "matrixget" to get copy 2's new transformation matrix<BR><DIV><BR class="khtml-block-placeholder"></DIV><DIV>I would imagine that copy 2's matrix is essentially all translation components (i.e. the upper 3x3 is all zeroes or near-zeroes) so all you need to do to place additional copies to multiply the translation components by 2, 3, etc.</DIV><DIV><BR class="khtml-block-placeholder"></DIV><DIV>--Eric<BR><DIV><DIV style="margin-top: 0px; margin-right: 0px; margin-bottom: 0px; margin-left: 0px; "><BR class="khtml-block-placeholder"></DIV><DIV style="margin-top: 0px; margin-right: 0px; margin-bottom: 0px; margin-left: 0px; "> Eric Pettersen</DIV><DIV style="margin-top: 0px; margin-right: 0px; margin-bottom: 0px; margin-left: 0px; "> UCSF Computer Graphics Lab</DIV><DIV style="margin-top: 0px; margin-right: 0px; margin-bottom: 0px; margin-left: 0px; "> <A href="mailto:pett@cgl.ucsf.edu">pett@cgl.ucsf.edu</A></DIV><DIV style="margin-top: 0px; margin-right: 0px; margin-bottom: 0px; margin-left: 0px; "> <A href="http://www.cgl.ucsf.edu">http://www.cgl.ucsf.edu</A></DIV></DIV><BR></DIV><DIV><BR class="khtml-block-placeholder"></DIV></BODY></HTML>