Hi everybody

As some of you will know I have been attempting to model rough water.

I could not understand why I had no control of the textures until I tried
adding some transparent cones for the spray - they showed...I eventually
traced the problem to ior, turn the ior off in the water HF and the cones
became transparent.

The same applies to stacked hf, the ior in the water makes some of the
higher hfs (I think the parts above the water surface)visible.

Unfortunately turning off the ior changes the waves considerably

Is this a variant of the double illumination bug? is there a fix?

I can partially fix it by placing other completely transparent Hf in the
stack but this only partially solves the prob and I hav'nt been able to work
out the mechanics of it, let alone understand or control it.

any ideas?

Mick

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Watch out for total internal reflection.  If the angle of incidence is
too shallow (the threshold angle is dependent on IOR), it will be reflected
instead of refracted.

-Nathan

Mick Hazelgrove wrote:
> 
> Hi everybody
> 
> As some of you will know I have been attempting to model rough water.
> 
> I could not understand why I had no control of the textures until I tried
> adding some transparent cones for the spray - they showed...I eventually
> traced the problem to ior, turn the ior off in the water HF and the cones
> became transparent.
> 
> The same applies to stacked hf, the ior in the water makes some of the
> higher hfs (I think the parts above the water surface)visible.
> 
> Unfortunately turning off the ior changes the waves considerably
> 
> Is this a variant of the double illumination bug? is there a fix?
> 
> I can partially fix it by placing other completely transparent Hf in the
> stack but this only partially solves the prob and I hav'nt been able to work
> out the mechanics of it, let alone understand or control it.
> 
> any ideas?
> 
> Mick

Post a reply to this message

Hmm, could It have someeething to do with the fact that a HF isn't a
"solid" that way??
Try using a box/HF intersection and I think you should get a better
result.



Mick Hazelgrove wrote:
> 
> Hi everybody
> 
> As some of you will know I have been attempting to model rough water.
> 
> I could not understand why I had no control of the textures until I tried
> adding some transparent cones for the spray - they showed...I eventually
> traced the problem to ior, turn the ior off in the water HF and the cones
> became transparent.
> 
> The same applies to stacked hf, the ior in the water makes some of the
> higher hfs (I think the parts above the water surface)visible.
> 
> Unfortunately turning off the ior changes the waves considerably
> 
> Is this a variant of the double illumination bug? is there a fix?
> 
> I can partially fix it by placing other completely transparent Hf in the
> stack but this only partially solves the prob and I hav'nt been able to work
> out the mechanics of it, let alone understand or control it.
> 
> any ideas?
> 
> Mick

Post a reply to this message

Spider <spi### [at] bahnhofse> wrote:
: Hmm, could It have someeething to do with the fact that a HF isn't a
: "solid" that way??

  HF is as solid as a plane.

-- 
main(i,_){for(_?--i,main(i+2,"FhhQHFIJD|FQTITFN]zRFHhhTBFHhhTBFysdB"[i]
):5;i&&_>1;printf("%s",_-70?_&1?"[]":" ":(_=0,"\n")),_/=2);} /*- Warp -*/

Post a reply to this message

Nieminen Mika wrote:
> 
> Spider <spi### [at] bahnhofse> wrote:
> : Hmm, could It have someeething to do with the fact that a HF isn't a
> : "solid" that way??
> 
>   HF is as solid as a plane.
ok.
I havent experimented with the solidity of it..
. 
> --
> main(i,_){for(_?--i,main(i+2,"FhhQHFIJD|FQTITFN]zRFHhhTBFHhhTBFysdB"[i]
> ):5;i&&_>1;printf("%s",_-70?_&1?"[]":" ":(_=0,"\n")),_/=2);} /*- Warp -*/

Post a reply to this message

On 10 Apr 1999 19:33:04 -0500, Nieminen Mika <war### [at] cctutfi> wrote:

>Spider <spi### [at] bahnhofse> wrote:
>: Hmm, could It have someeething to do with the fact that a HF isn't a
>: "solid" that way??
>
>  HF is as solid as a plane.

Which is to say "not as solid as a sphere."  At least, not as far as
media is concerned.  But both should work okay with ior, as POV
doesn't need to know the exit point for simple refraction
calculations.  Is it possible that our protagonist is not specifying
the same IOR for the cones?

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Mick Hazelgrove wrote in message <370f663b.0@news.povray.org>...
>Hi everybody
>
>As some of you will know I have been attempting to model rough water.
>
>I could not understand why I had no control of the textures until I tried
>adding some transparent cones for the spray - they showed...I eventually
>traced the problem to ior, turn the ior off in the water HF and the cones
>became transparent.
>
>The same applies to stacked hf, the ior in the water makes some of the
>higher hfs (I think the parts above the water surface)visible.
>
>Unfortunately turning off the ior changes the waves considerably
>
>Is this a variant of the double illumination bug? is there a fix?


I don't know if it is, but the double illumination bug effects only smooth
height fields (as opposed to non-smooth ones that is).  You could try
removing the smooth keyword (if present) and seeing if that effects
anything.  Otherwise, I doubt it's a double_illuminate problem...


Matt

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