PITView calculations giving strange results


I’m studying the distribution of daylight in a model, and I’ve done som PIT calculations with an overcast sky. But the spread of daylight inside, doesn’t seem to be just right.

Running the simulation with RadPar detail level 0 or 1, seems to have no internal reflections.
Running the simulation with detail level 2, gives smooth visualizations, but the internal spread is not physically correct. e.g. the calculation seems to not include the incidence angle of the glazing, as there is light in the corner itself.

I tried running it with other radiance parameters:
-aa .1 -ab 7 -ad 2048 -ar 0 -as 1024 -dr 3 -ds .15 -lr 8 -lw .000001 -dc .75 -dp 512 -dt .05 -st .15 -dj .7

This takes a looooong time, and the results are then quite spotty, but the internal spread seems to be more correct.

There is also something happening outside, as the window sills have uneven lux levels:

This happens also with detail level 2:

The file is also attached.
PIT- v 1.gh (145.4 KB)

I’ve also rendered the same geometry, using Climate Studio, and this goes much faster and looks better:

But would prefer to use LBT, for various reasons, among these that one can produce several PITViews in a batch and the connection to pollination cloud.

Any ideas as to what is happening?

Hi @LittleBuddha,

Can you internalize the geometry in Grasshopper and reupload the file?

Hi @mikkel

PIT-internalized.gh (292.8 KB)

haven’t done this before, so hope it works…

Hi @LittleBuddha,

Can you try to reduce the model? In particular remove this room that makes the boundaries of the scene unnecessarily large. You can probably also reduce the size of the ground plane. Then maybe look at HB Ambient Resolution to set the -ar parameter.

Thanks @mikkel for the HB Ambient Resolution tip, hadn’t used that one.

Brute forced the outside results, by installing Accellerad, and running with these radiance parameters:
-aa 0.0 -ab 4 -ad 4096 -ar 1024 -dc 0.5 -dj 0.5 -dp 256 -dr 1 -ds 0.25 -dt 0.25 -lr 6 -lw 0.01 -pj 0.9 -ps 4 -pt 0.1 -ss 0.7 -st 0.5 -as 1024

But I still have som issues with the internal view.

Working on that now.

Thanks for sharing @LittleBuddha

I also tested your model with different rad parameters, including -ar @mikkel. Also getting some strage results.

I noticed the low lux values, can it be due to the sky model?

Thanks Mr TK.

Will experiment more, and get back…