Alain <ele### [at] netscapenet> wrote:
> Andreas nous illumina en ce 2008-07-06 08:46 -->
> > Hi!
> >
> > I'm relatively new to POV-Ray, and I have some questions regarding a small
> > project I'm working on.
> >
> > For one thing, I'd like to create a lava flow of sorts, which would illuminate
> > the surrounding area. I've tried to make the flow hollow and use it as a light
> > source, but that didn't seem to work. So I made a flow with high ambiance
> > levels, and used radiosity, which would light up the the canal in which the
> > lava flows. However, this does not light up any objects further away. Any
> > suggestions on this matter?
>
> "hollow" enable an object to contain some media, it don't have any other function.
> You can make the lava transparent, or add "no_shadow", and put some light_source
> inside of it.
> Your idea of using radiosity is the more realist way of doing it. If it don't
> light up farther objects, it can be because:
>   - there is some obstacle between the "lava" ant that object. (very probable)
> If the lava is inside a trench, it will only light the trench and things that
> are over it.
>   - the object is to far away for the "light" coming from the lava to have a
> significant offect. Give the lava a very high ambient value to thest that, like
> ambient 100000. ANYTHING that is still dark don't have a line of sight to the lava.
>   - you may not have enough radiosity ray traced and you miss the lava. Try
> increasing the count value, it can go as high as 1600, to something like 200 to 500.
> If the scene is inside something like a cave or tunel, you may need to increase
> recursion_limit to 4, 5, or maybe some more. Don't overdo that, there is a point
> of reduced return.
>
> Do you have some fumes that you'd like to be lighted by the lava? In that case,
> you need to have actual lights as radiosity don't shine on media.
>
> >
> > The second question is about texturing. I'd like to make a whip (bullwhip to be
> > exact..), but I can't seem to get the texture (braids) to follow the surface.
> > So far I've tried sphere_sweep and a 3D model which I've made, but nothing
> > seems to work correctly.
> > On the topic of texturing, I've thought about using two layered textures rotated
> > to be perpendicular to each other to simulate the braids, but does anyone have a
> > better approach?
> >
> > Thank you for any tips and tricks you can share
> >
> >
> > Andreas
> >
> >
> You can go the hard way of using 3 sphere_sweep to actualy make your braid. You
> can then use a very plain texture as the aspect will be provided by the actual
> shape. In this case, I'd recomend using 3 slightly different textures, one for
> each strip.
> If you use a modeler, you should turn on uv maping. Apply the texture to the
> straight whip, then make it bend and twist. That way, the texture should follow
> the shape.
>
> --
> Alain
> -------------------------------------------------
> Experience demands that man is the only animal which devours his own kind,
> for I can apply no milder term to the general prey of the rich on the poor.
> Thomas Jefferson

The lava problem is fixed now; it was the distance which caused the problem, so
I just scaled things down a bit.

As for the whip, it seems like the sphere_sweep method is quite complicated, and
I do not have enough math skills to actually implement something like that, at
least not for a coiled whip.
Am I correct in assuming that I can use POV-Ray textures for the 3D mesh, and
still get the UV mapping to work seamlessly?

Thanks


Andreas

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