On Mon, Mar 9, 2009 at 7:09 AM, Jason Grout <[email protected]> wrote: > I've noticed on this and several other interacts I've done where the > tangent plane looks ugly because right around the point of tangency, > jmol apparently gets confused with the two surfaces. > > Is this numerical error? Is there anything we can do to fix it or at > least make it better?
In computer graphics, this is known as "Z-fighting". You can do a google search to see lots of discussion of the problem. There's no really satisfying solution in general, although there are lots of things that can help in special cases. For this special case of drawing tangent planes, the first thing I would try is to manually (in your interact) shift the tangent plane so that it's not actually tangent, but sits 0.01 units (say) off the surface. Hopefully this will fix the problem. Of course, this is easier said than done... to make this work with arbitrary functions, you would ideally compute the local curvature to decide which direction to shift the tangent. (And if the function is saddle-shaped, there's no way to shift the plane and still look correct.) Carl --~--~---------~--~----~------------~-------~--~----~ You received this message because you are subscribed to the Google Groups "sage-edu" group. To post to this group, send email to [email protected] To unsubscribe from this group, send email to [email protected] For more options, visit this group at http://groups.google.com/group/sage-edu?hl=en -~----------~----~----~----~------~----~------~--~---
