Thomas de Groot <tho### [at] degrootorg> wrote:
>
> To test this I need the fFinal() fInpX() fInpY() fInpZ() functions too.

Okay, maybe Thomas has figured this out too. I was just trying to think it out
using other functions and got nowhere but I did suspect something I had happen
before:

I ran your files as animation and found nothing wrong...
except after about clock=0.52 and until about clock=0.72

What's going on is simply a case of max_gradient 50 being too low for that
particular segment of frames.

That isosurface requires up to max_gradient 60 from what I found during that
part of the animation.

Try this instead of max_gradient:

evaluate 15,4,0.7

That will give a minimum gradient value with a multiple of 4 (=60) and change
rate.
Better yet, read about that at:

http://wiki.povray.org/content/Reference:Isosurface

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On 3/8/2017 4:41 AM, omniverse wrote:
> Thomas de Groot <tho### [at] degrootorg> wrote:
>>
>> To test this I need the fFinal() fInpX() fInpY() fInpZ() functions too.
>
> Okay, maybe Thomas has figured this out too. I was just trying to think it out
> using other functions and got nowhere but I did suspect something I had happen
> before:
>
> I ran your files as animation and found nothing wrong...
> except after about clock=0.52 and until about clock=0.72
>
> What's going on is simply a case of max_gradient 50 being too low for that
> particular segment of frames.
>
> That isosurface requires up to max_gradient 60 from what I found during that
> part of the animation.
>
> Try this instead of max_gradient:
>
> evaluate 15,4,0.7
>
> That will give a minimum gradient value with a multiple of 4 (=60) and change
> rate.
> Better yet, read about that at:
>
> http://wiki.povray.org/content/Reference:Isosurface
>
>

That seems to work. Thank you!

Mike

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On 8-3-2017 12:52, Mike Horvath wrote:
> On 3/8/2017 4:41 AM, omniverse wrote:
>> Thomas de Groot <tho### [at] degrootorg> wrote:
>>>
>>> To test this I need the fFinal() fInpX() fInpY() fInpZ() functions too.
>>
>> Okay, maybe Thomas has figured this out too. I was just trying to
>> think it out
>> using other functions and got nowhere but I did suspect something I
>> had happen
>> before:
>>
>> I ran your files as animation and found nothing wrong...
>> except after about clock=0.52 and until about clock=0.72
>>
>> What's going on is simply a case of max_gradient 50 being too low for
>> that
>> particular segment of frames.
>>
>> That isosurface requires up to max_gradient 60 from what I found
>> during that
>> part of the animation.
>>
>> Try this instead of max_gradient:
>>
>> evaluate 15,4,0.7
>>
>> That will give a minimum gradient value with a multiple of 4 (=60) and
>> change
>> rate.
>> Better yet, read about that at:
>>
>> http://wiki.povray.org/content/Reference:Isosurface
>>
>>
>
> That seems to work. Thank you!
>
> Mike

I was not yet that far, but I was thinking in the same direction. 
Evaluate is a good tool to use in this context.

-- 
Thomas

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I haven't had a chance to look over the isosurface functions, but it looks like
the final shape is a parallelpiped.
If so, couldn't you just make a box and shear it in all 3 directions?
Simpler and lots faster, if that's the case.

I enjoy these color models you work on.
They are very pleasing to my eye.
Keep up the good work!  :)

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I am having the same problem in a different scene posted in p.t.s-f.

This time I used "evaluate" from the start. Render times are long but 
artifacts still appear.


Mike

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On 3/8/2017 10:02 AM, Bald Eagle wrote:
> I haven't had a chance to look over the isosurface functions, but it looks like
> the final shape is a parallelpiped.
> If so, couldn't you just make a box and shear it in all 3 directions?
> Simpler and lots faster, if that's the case.
>
> I enjoy these color models you work on.
> They are very pleasing to my eye.
> Keep up the good work!  :)
>

No, I don't want to do this.


Mike

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On 3/8/2017 11:58 AM, Mike Horvath wrote:
> I am having the same problem in a different scene posted in p.t.s-f.
>
> This time I used "evaluate" from the start. Render times are long but
> artifacts still appear.
>
>
> Mike


Disregard.


Mike

Post a reply to this message

Mike Horvath <mik### [at] gmailcom> wrote:
> I am having the same problem in a different scene posted in p.t.s-f.
>
> This time I used "evaluate" from the start. Render times are long but
> artifacts still appear.

Yow! I used max_gradient alone to see what POV-Ray was saying it wanted that to
be and its way beyond what the other isosurface evaluate parameters were.
Which BTW I finally ended up using MinFactor=0.7 to prevent any missing portions
of that one.

This current isosurface using max_gradient 10000 (sans evaluate) is rendering 5
minutes at only 160X120 resolution, incomplete of course.

Render message told me it needed max_gradient 7131910.500, so that really puts
the evaluate numbers up there and the render time is obviously going to increase
dramatically.

Sorry I don't have a solution, can only tell you that much. If there's a way to
reduce render times and still get a complete isosurface for this one I sure
don't know the answer. Unless something can be manipulated to do so and someone
else knows how to go about it anyway.

Bob

Post a reply to this message

On 3/8/2017 1:15 PM, omniverse wrote:
> Mike Horvath <mik### [at] gmailcom> wrote:
>> I am having the same problem in a different scene posted in p.t.s-f.
>>
>> This time I used "evaluate" from the start. Render times are long but
>> artifacts still appear.
>
> Yow! I used max_gradient alone to see what POV-Ray was saying it wanted that to
> be and its way beyond what the other isosurface evaluate parameters were.
> Which BTW I finally ended up using MinFactor=0.7 to prevent any missing portions
> of that one.
>
> This current isosurface using max_gradient 10000 (sans evaluate) is rendering 5
> minutes at only 160X120 resolution, incomplete of course.
>
> Render message told me it needed max_gradient 7131910.500, so that really puts
> the evaluate numbers up there and the render time is obviously going to increase
> dramatically.
>
> Sorry I don't have a solution, can only tell you that much. If there's a way to
> reduce render times and still get a complete isosurface for this one I sure
> don't know the answer. Unless something can be manipulated to do so and someone
> else knows how to go about it anyway.
>
> Bob
>

I think clipka told me to use this:

	#declare cie_fClip1 = function(X,A) {select(X-A,A,X)}
	#declare cie_fClip2 = function(X,A) {select(-(X-A),A,X)}
	#declare cie_fD = function(C) 
{abs(cie_fClip2(cie_fClip1(C,-0.1),1.1)-0.5)-0.5}

instead of this:

	#declare cie_fD = function(C) {abs(C-0.5)-0.5}

as a workaround.


Mike

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On 3/7/2017 12:21 PM, Mike Horvath wrote:
> I am trying to render the following isosurface.
>
> isosurface
> {
>     function {fFinal(fInpX(x,y,z),fInpY(x,y,z),fInpZ(x,y,z))}
>     threshold    0
>     accuracy    0.001
>     contained_by
>     {
>         box {0,1}
>     }
>     max_gradient    50    // was 20000
> }
>
> However, from certain angles there appear gaps or cuts in the surface,
> and you can see inside. The gaps disappear when viewed from other angles.
>
> Does anyone have any tips on how to fix this? I already tried scaling by
> 200 but it does not help.
>
>
> Mike

I wish I could replace these with meshes. Then I could make an animation 
with many frames.


Mike

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