Samuel Benge wrote:
>>
>> That is not true.  Black spots on isosurfaces can have multiple 
>> reasons, the most common being an insufficient max_gradient.  The idea 
>> of using interpolation for the final root position is good but it is 
>> not a panacea for all kind of isosurface problems.  In other words it 
>> will only improve the results if the isosurface root finder has 
>> already successfully found the root.
> 
> I understand this, but did you look at the comparison images? 
> Interpolation after the last step 'glues' the isosurface together, so it 
> doesn't have holes that really shouldn't be there in the first place. 
> The isosurface renders up to (and more than) two_times_faster. His patch 
> sure seems like a bug fix to me.

No, the examples Wolfgang shows on his page show the patch improving the 
results in cases of self shadowing and intersecting surfaces.  None of 
the samples shows a case where the root is not found reliably (no holes 
in any of the images).

There is no speedup either but a slight slowdown in fact, the faster 
results are due to the use of a higher accuracy value which will work 
well in cases like these where the accuracy is much smaller than the 
features of the isosurface function anyway but this can't be 
generalized.  A two times speedup in all isosurface renders because of 
this change is illusory.

Christoph

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