[Radiance-general] rendering with environment maps

[Thomas Bleicher]

You need to throw in an "-ab 1" (or higher) in the rvu line. The HDR image
does not count as light source and so does not "illuminate" objects with
the default of "-ab 0". If you had more geometry in the scene you would
notice that everything is dark. The only thing you see is the HDR image
itself in direct view or reflected in the sphere (reflection is calculated
independently of the light distribution).

Regards,
Thomas



On Mon, Jul 20, 2015 at 8:41 PM, Minjung Kim <mkim85 at gmail.com> wrote:

> Hi there,
>
> I have a question about rendering with environment maps. I set up a scene
> consisting of two spheres, one completely specular and one Lambertian, lit
> it with one of Paul Debevec's light probes (
> http://www.pauldebevec.com/Probes/). The specular sphere is rendering
> fine, but the Lambertian one is turning up completely black, and I have no
> idea why.
>
> My code looks like this:
>
> # make 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
>
> # make materials
> void plastic spec # specular
> 0 0 5 .5 .5 .5 1.000000 0.000000
>
> void plastic lamb # Lambertian
> 0 0 5 1 1 1 0.0 0.0
>
> # make spheres
> spec sphere sph1 # specular
> 0 0 4 -.5000000 0.000000 0.000000 0.300000
>
> lamb sphere sph2 # Lambertian
> 0 0 4  .5000000 0.000000 0.000000 0.300000
>
> I then ran it like this:
>
> oconv scene.rad > scene.oct
> rvu -vtv -vv 10 -vh 10 -vp 0 -10 0 scene.oct
>
> When I do this, I get a mirrored sphere and a completely black sphere. To
> make sure that the problem wasn't with my code, I downloaded this sample
> code from Debevec's website (http://www.pauldebevec.com/RNL/Source/).
> When I changed the materials in the .rad file to be Lambertian (lines
> 182-190 in rnl_scene.rad), the objects rendered as completely black.
>
> Has anybody ever run into this problem before? I am using RADIANCE 4.2, on
> OS X 10.7 (home) and OS X 10.9 (work).
>
> Regards,
>
> MJ
>
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