An invisible light source

Hello community,

I have a problem that the luminance of the central spotlight on the ceiling (you may not even know it exists in the attached image) disappears when rendering with Radiance such as the following image:

The spotlights installed in the room, with which are 19 degrees (center of the room) and 31 degrees (right), are converted to RAD using the following commands and rendered;

%ies2rad -t default -dm/1000 -o ies/19 -c *** -m 0.06 ies/19.txt
%xform -t 1500 1500 2250 ies/19.rad > m_light/19.rad
%ies2rad -t default -dm/1000 -o ies/31 -c *** -m 0.1 ies/31.txt
%xform -t 2250 1500 2250 ies/31.rad > m_light/31.rad
%oconv materials.rad room.rad m_light/19.rad m_light/31.rad > room.oct
%rpict -vp *** -vd *** -vv 120 -vh 120 -vu 0 0 1 -ab 2 -aa .5 -ar 64 -ad 64 -as 32 -x 800 -y 800 -t 10 room.oct > room.hdr

19.txt and 31.txt mean ies data downloaded by a manufacturer.What kind of operation is required to output correctly as the light source like the right one?

If the light source is at an angle away from the camera, or has zero output in the direction of the camera, then it will not be visible. Did you try rendering a view looking up from the floor, just to make sure it’s visible where you know it should be?

Hi Greg,

I appreciate your quick response.

As you pointed out, it seems that the light source is invisible due to the positional relationship between the light distribution angle and the camera. In fact, when I installed a light source with a wider light distribution angle in the center of the room, I was able to output correctly.

I couldn’t come up with a basic hypothesis due to my lack of study, but thanks to you, I was able to solve it !!

thanks a lot,