[Radiance-general] rendering with environment maps

[Minjung Kim]

Hi,

1) Perhaps your use of the "glow" material for the environment box stops
> the direct calculation from reaching the light source? Can you post the
> definition of your light source? I know a combination of HDR mapped to a
> sky dome and other light sources can be done but I'm not sure if this works
> with a box, too.
>

# Direct source
void light lt
0
0
3 1 1 0  # The light colour is yellow, so if my white ball is lit yellow, I
know that this light has an effect.
             # I've also tried varying the intensity of the RGB values here
with respect to the RGB values of the environment map.

lt source ltsource
0
0
4 0 -1 1 1

# Environment map
void colorpict uff
9 red green blue uffizi_probe.hdr angmap.cal sb_u sb_v -rx 90
0
0

uff glow uff_glow
0
0
4    1    1    1    0

!genbox uff_glow boxenv 100 100 100 -i | xform -t -50 -50 -50



>
> 2a) You can render the image of the environment map on the reflecting
> sphere separately from the main scene and then just combine the two images.
> You won't have the lighting pattern on the mirrored object, though. Perhaps
> there is a way to capture the lighting pattern with a lambertian material
> and multiply the values from both images? You'd have to make sure that your
> environment texture captures accurate lighting data.
>
> 2b) Instead of reflecting a texture in the mirror ball you could just
> apply the texture directly to the mirror. What real-world physical effect
> do you want to simulate?
>

My goal is to be able to render a completely specular object in different
scenes ("worlds," let's say), e.g., white noise, 1/f noise, polka dots, &c.
Normally, I would set up a scene thus:

- put the object in the world origin
- place a light source or light sources
- place a giant box around the scene, and texture the inside of the box
with the desired world (e.g., white noise)

But what I actually want to do is use naturalistic lighting, captured from
light probes, hence my question. But maybe this is a nonsensical thing to
do, since the light probes contain scene structure in there? I'm not sure.

Thanks so much for your help!

Regards,

MJ
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