[Radiance-general] Sharper shadows using a light probe

[Greg Ward]

Hi Tarik,

Ian is right about the environment determining the sharpness of your  
shadows as much as your object geometry.  You should also consider  
using the new mksource program, especially if your environment map  
contains the sort of small, intense sources that should generate  
shadows.  However, to do so, you'll need to map your light probe onto  
a distant glow source rather than a large box.

See the postings from last month on mksource, starting with:

     http://www.radiance-online.org/pipermail/radiance-general/2005- 
April/002602.html

-Greg

> From: Ian Tester <ian at testers.homelinux.net>
> Date: May 25, 2005 7:08:56 AM PDT
>
> Tarik Rahman wrote:
>
>> Hi there
>> When illuminating a scene, say objects on a table, using a light  
>> probe, is there
>> any way to get sharper, darker shadows (of the objects on the  
>> table)? I  use the
>> genbox command for the light map, obviously the light is not as  
>> focused because
>> it's spread out over the large box 100 100 100. If the surface is  
>> specular,
>> nice reflections are rendered but if it is purely diffuse, the  
>> shadows hardly
>> occur.
>>
>
> I would think that for a light probe, the probe image would be more  
> important than the geometry it's mapped on to. What is your light  
> probe like? Does it have a small source of light, or is it spread  
> over a large area? If your light probe image has a large source of  
> light, or many smaller ones spread out, then the results you  
> describe sound about right.
>
> bye
>