[Radiance-general] Re: physically-based landscapes

[Santiago Torres]

Hello again,

Thank you Peter for your reply. The animation is really impressive. And I
understand your point about parallax error. I guess there`s always a price
with either method since there`s only one image map to start with. If I
understood well Greg`s post, there are different ways to do this, each with
pluses and minuses, depending in window size or distance to outside objects,
etc. So, I`ve been trying what I could through the weekend with mixed
results.

First, I tried to map a rendered fisheye image of the sky to a source,
replacing gensky, but there`s something strange with my transformations (the
sky appears diamond shaped...:/), so I need to review the mapping, but it
seems to be working. Like Rob said, the possibilities are really cool [Hi
Rob!]

I was thinking on taking HDRs of inside and outside of a building (at the
same time) and then compare the results with inside renders using a mapped
sky for outside. Has anybody tried it?

OTOH, I defined a simple room with a sky outside (using gensky) and then
took fisheye images of the sky and the view out of the window. I followed
Greg`s instructions with fiseye.cal, and it worked perfectly (of course!)
But when taking rtrace measurings, there was a slight difference between the
model with the original sky and the mapped model (about 4.5%) Could this be
because of the relative size of the window (1/9 of the wall in this case)?
or maybe I`m doing something wrong? I assume the rtrace parameters have
nothing to do since they`re the same in both cases, but maybe I`m wrong
(again?)

I understand all this was meant to help Rob with a particular practical
problem but I was interested in the more general case. I am now in the
process of measuring daylight in a real building, and I thought this could
be a good way to validate results with renderings (I will nedd to use
renderings later) Then, sorry if I diverge from the original post. And
thanks again for your help.

Santiago.