Tom York wrote:
>Couldn't you try applying a well-chosen normal pattern to a simple thin box
>(aligned with the bullet but facing the camera as far as possible) with a
>single ior? I also had this variable ior problem a long time ago, but
>controlling the refraction with a normal pattern or more directly by
>choosing an appropriately shaped object proved faster and didn't have the
>max_trace_level problem. I've used this to generate "heat-wave" type
>distortions in a horizon line and simulate odd lenses.
>

Well... I've seen one animation of a heat wave in this newsgroup. The main
problem is that, in my case, the effect of the variable refraction is not
covered in all the camera viewing area. This
means that a box or a plane with a disturbed normal just won't work

I'm wondering if I can simplify the scene, speed up the rendering and
decrease memory, all at once by changing POV's source code, and doing an
alternative method of "refraction". This method would not follow any
physical law, but it would change the direction of the ray by evaluating
some noise at the intersection point. So, the ray direction will be changed
when it passes through the object, making it look "refracted".

In fact, the model isn't very realistic (because no physics are used at
all), but in this case, when the heated air's density is random, it would
not look very strange. Of course, it would need some tweaks, as taking in
account the direction of the ray vs. the normal to make it more realistic,
and maybe the distance the ray travels through the refracting object.

This is a model wich came up in my simple mind, so any sugestions are
largely welcome.
I apologize if I wasn't clear enough. Any questions?

Thanks in advance

Leonardo

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