```Date: Mar 9, 2013 5:26 AM
Author: David Park
Subject: Re: dark halo around gaussian peak in Plot3D?

Michael,It looks to me like a numeric problem with very small numbers.  You can workaround it by clipping the function. Here I also scaled up the function by100 just to get a convenient range.Plot3D[100 Clip[   PDF[BinormalDistribution[0], {x, y}], {10^-150, 20}], {x, -40,   40}, {y, -40, 40}, PlotRange -> All, PlotPoints -> 30, Mesh -> None] If you decrease the lower Clip value by much you will get the "dark halo"back. It seems to be associated with the front FaceForm losing its color.Plot3D[100 Clip[   PDF[BinormalDistribution[0], {x, y}], {10^-200, 20}], {x, -40,   40}, {y, -40, 40}, PlotStyle -> Directive[FaceForm[Gray, Red]], PlotRange -> All, PlotPoints -> 30, Lighting -> "Neutral", Mesh -> None]David Parkdjmpark@comcast.net http://home.comcast.net/~djmpark/index.html From: Michael B. Heaney [mailto:mheaney@alum.mit.edu] Here is simple example that demonstrates the problem:Plot3D[PDF[BinormalDistribution[0], {x, y}], {x, -40, 40}, {y, -40, 40}, PlotRange -> All, PlotPoints -> 200]Thanks,MichaelOn Thu, Mar 7, 2013 at 8:49 PM, Bob Hanlon <hanlonr357@gmail.com> wrote:> I don't see a "dark halo" with the following>> Plot3D[>  PDF[BinormalDistribution[0], {x, y}],  {x, -3, 3}, {y, -3, 3}]>> Can you send a simple example that demonstrates the problem?>>> Bob Hanlon>>> On Thu, Mar 7, 2013 at 10:51 PM, Michael B. Heaney > <mheaney@alum.mit.edu>> wrote:> >> > Hi,> >> > When I plot a gaussian peak in Plot3D, there is a dark halo around > > the peak. Why is this? How can I get rid of it?> >> > Thanks,> >> > Michael> >> > --> > ----------------------------------------------------------> > Michael B. Heaney> > 3182 Stelling Drive> > Palo Alto, CA 94303 USA> > mheaney@alum.mit.edu> > www.linkedin.com/in/michaelbheaney> > ----------------------------------------------------------> >> >>------------------------------------------------------------Michael B. Heaney3182 Stelling DrivePalo Alto, CA 94303 USAmheaney@alum.mit.eduwww.linkedin.com/in/michaelbheaney----------------------------------------------------------
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