Filter the surface to display only values above a given "trigger"

[GoogleCodeExporter]

What steps will reproduce the problem?
1.
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What is the expected output? What do you see instead?

What version of the product are you using? On what operating system?

Please provide any additional information below.

Original issue reported on code.google.com by alan.rad...@gmail.com on 20 Mar 2012 at 6:09

[GoogleCodeExporter]

Sometimes we want to be able to plot values without reference to the edge of 
the array - in other
words set a discriminator value above which values are plotted but below which 
nothing appears on the graph. Otherwise one ends up with only being able to 
plot rectangular shaped functions (x,y)  or else having large (un-real) jumping 
lines at the edge of values where no value has been set. (discriminator 
nominally 0 - but settable) 

Original comment by alan.rad...@gmail.com on 21 Mar 2012 at 3:19

[GoogleCodeExporter]

It's possible to workaround it right now, using a "versatible" surfacemodel: 
value below the trigger return NaN value above return the value.

Anyway it seem a good way to "explorer" a 3D function anyway.

Original comment by e...@ericaro.net on 21 Mar 2012 at 7:56

• Changed title: Filter the surface to display only values above a given "trigger"
• Changed state: Accepted
• Added labels: Type-Enhancement
• Removed labels: Type-Defect

[GoogleCodeExporter]

Another point relates to the fact that the graph should not display anything 
whatsoever where a value is
below the trigger - and also importantly the edge of the function should be 
bounded with a line - so
if the accepted values made a circular shape when looked at from above then the 
outline of the shape should
be a connected line - this is to avoid "ragged" edges - wheras before the edges 
were nicely jioned into a square shape here they would make any shape 
whatsoever.  By the way this software is fantastic - thankyou and well done. - 
Alan Radley

Original comment by alan.rad...@gmail.com on 22 Mar 2012 at 1:05