Hi ccp4bb, Apologies for a cross-post. I previously asked this question on the pymol-users mailing list, but I thought I'd ask here as well, in case someone who doesn't follow that bb might have run into my problem rendering maps in PyMol. I'm starting to think it's a non-trival problem to solve.
I'm drawing a mesh based on a ccp4 map exported from coot. To get finer sampling, I use the map_double command (twice sequentially, but the problem is visible after the first). Doubling the map introduces a discontinuity. The second doubling introduces a gap, but even even the first has a visible distortion. (see linked images below) This discontinuity lines up with the unit cell boundary, so it has something to do with sampling at the unit cell edge (the cell boundary is faintly visible in the background of the linked images). Not sure if there's a simple fix I'm overlooking or if it's a fundamental limitation of the sampling algorithm. Any help you can provide would be great! I've linked images of the same map at all 3 samplings below: Parent map: http://imgur.com/i46YH6r Doubled once: http://imgur.com/Vy8oJfx Doubled twice: http://imgur.com/q3gO0cI Thanks for your indulgence! Shane Caldwell McGill University
