[Radiance-general] ltview, a light source viewer

[Rob Guglielmetti]

Axel Jacobs wrote:

> Hi Rob
> 
> I've tried ltview with this luminaire ... <snip>

> I can't see which one of the default rvu parameters causes this. Could 
> be one of the -a* or -d*, but I am not sure...
> My feeling is that -av should be set to zero. The lamp might be very 
> dim, in which case it's washed out with the ambient. Is it really 
> necessary to involve rad? this is done in objview, because you don't 
> know upfront how big the scene is etc.

Hi Axel,

Hmm.  The only parameters I change in the script are -ab (1 from 0) and 
-ds (.15 from 0).  I suppose rad is making some other changes?  The 
reason I'm using rad is because with the addition of the -bs option the 
script also dosen't know how big the scene is.  I suppose I could change 
it to set up a default view like you have, and scale the -vp if the user 
enters a different value for -bs.  I was trying to change as little of 
objview as possible though.  Anyone who's seen any of my programming 
knows why. =8-)

I set -ab 1 because the scene just looks better, the bounce reveals 
fixture geometry and glow sources; I thought by scaling the room with 
-bs you could always have the light source close to the room surfaces, 
minimizing the ambient washout problems.

Your erco source file shows a tiny ring (radius of .0175), but your 
room/box is 10 units square (in your example).  Did you maybe assume 
meters for one thing and milimeters for the other?  I did "ltview -bs .2 
erco.rad" and it looked fine (and there is approx. 1730 Lux under the 
fixutre, .1 units away).  I can't read an ies2rad -> rad file and spot 
errors easily (hence this ltview utility), but I suspect maybe there's a 
units mismatch.  That doesn't explain why your test scene at 10 units 
square looks OK, though.  Hmmm.

Could you double-check your ies2rad input?

----

      Rob Guglielmetti

e. rpg at rumblestrip.org
w. www.rumblestrip.org