William F Pokorny <ano### [at] anonymousorg> wrote:
> On 06/23/2013 04:27 AM, Le_Forgeron wrote:
> > Le 22/06/2013 15:57, Thomas de Groot nous fit lire :
> >> On 22-6-2013 10:38, Le_Forgeron wrote:
> > So, I cannot duplicate the original issue, at least on the unix port.
> >
> >> Whatever value for max_gradient I use (too low or too high) the
> >> expected warning never appears in the message window like it used to
> >> do. I need it to determine the values for evaluate.
> >
> > The only difference is less context.
> > Or is it a Windows specific issue ? (I hope not)
> >
> It seems to be the case the gradient warnings are only generated if the
> isosurface is naked. If it is wrapped in an object as was the case with
> my thread safety example, we get no warnings.
>
> Inserting some comments in the IsoSurface::DispatchShutdownMessages code
> as follows:
> //------------------------ code -------------
> mginfo->max_gradient = max((DBL)temp_max_gradient,mginfo->max_gradient);
>
>     cerr << "In DispatchShutdownMessages" << endl;
>          if (isCopy == false)
>          {
>     cerr << "isCopy false" << endl;
>                  FunctionCode *fn = vm->GetFunction(*(Function));
>
>                  if (fn != NULL)
>                  {
>     cerr << "fn not NULL" << endl;
>                          if (eval == false)
>                          {
>     cerr << "eval == false" << endl;
>                                  // Only show the warning if necessary!
> //------------------------ code -------------
> it looks like the "if (isCopy == false)" does not test positive when the
> isosurface is wrapped in an object, but it does when the isosurface is
> naked.
>
> Bill P.

First I can confirm Thomas issue, but I cannot remember if it was the change
from 3.6 to 3.7 or from a release candidate of 3.7 to the next as the
max_gradient warnings disappeared. My quick work around is simple: if you see
black holes: rise it. If you trace an isosurface (exspecially for camera
position) and you yield a black image you most likely dropped through a black
whole due to this issue: rise it too. This occurs for example using randomized
camera locations within Jaime's project tierra. It would be fine to have a guess
how much to rise it as we had in the past, which would save the one or other
rendering hour of course.

But what is a "naked isosurface"? Isosurfaces must be contained in a container
object. Having Poser, I only can imagine "naked" mesh objects ... ;-)

Best regards,
Michael

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