<html><head><meta http-equiv="Content-Type" content="text/html charset=windows-1252"></head><body style="word-wrap: break-word; -webkit-nbsp-mode: space; -webkit-line-break: after-white-space; ">Hi Joel,<div><br></div><div> I don't think surface curvature will be helpful understand the differences between two EM maps. But I was curious what it would look like. So here's a Python script and an image on a simulated map at 15 Angstroms. You use the script by opening your map, selecting the surface (ctrl-click on it), then open the curvature.py script (menu File / Open…). Here's a description of the method it uses from the comments at the top of the curvature.py file.</div><div><br></div><div><div># Color selected surface pieces by mean curvature.</div><div>#</div><div># Gray at the average curvature value over the surface, and blue and red</div><div># at +/- 3 standard deviations of curvature values across the surface.</div><div>#</div><div># The curvature is estimated from the vertices and normals of the triangulated</div><div># surface in simple way which will show artifacts from non-isotropic meshes.</div><div># For each triangle edge it computes the normal vector rotation from one vertex</div><div># to the other divided by the edge length. The vertex mean curvature is the</div><div># mean of the curvatures computed for each edge.</div><div>#</div></div><div><br></div><div>And the steps to make the example image</div><div><br></div><div><span class="Apple-tab-span" style="white-space:pre"> </span>open 1grl</div><div><span class="Apple-tab-span" style="white-space:pre"> </span>molmap #0 15 grid 2 model #1</div><div><span class="Apple-tab-span" style="white-space:pre"> </span>select #1</div><div><span class="Apple-tab-span" style="white-space:pre"> </span>open ~/Desktop/curvature.py</div><div><br></div><div> Tom</div><div><br></div><div><br></div><div></div></body></html>