rpict settings & open area relation

Dear Greg,

I uploaded some images to: www.ezct.net/radiance/rpict_area_settings/
Currently I'm using the following rpict parameters:

rpict.exe -vf render.vf -ab 3 -ar 512 -ad 512 -ps 1 -as 512 -x 1500 -y 1500

which is pretty basic, but as you'll see in the last frame is fast and
artifact free, whereas there's little open area in the initial frame, which
of course leads to artifacts.

I'm rendering out a animation which shows a cube dissolving in space, each
frame cuts out a certain area of the box, slowly leaving it to dissolve.
I figure having the open area parameter drive the Radiance parameters would
be a good approach, wouldn't it?

Cheers,

Jelle.

···

******
Hi Jelle,

What would be useful is a web link to some of your images, so we can
see your model and the artifacts you are facing.

-Greg
******

Hi Jelle,

Yes, it definitely helps to know what we're talking about. 1000 words/picture, at least!

The problem with the initial frames is that there aren't enough ambient divisions to find the few and tiny holes you have. I recommend setting a much larger value for -ad at the beginning, and you can gradually relax this as you get more holes in your space. Just guessing, I'd say you need at least -ad 4096 for the initial frame, which will take 5 times longer to compute. (I don't think you need to increase -as -- 512 should be enough.)

An alternate approach is to use illums in your openings with the outside distribution mapped to them, as described in Tutorial 0 (Chapter 1 of RwR which is available online if you don't have it from <http://radsite.lbl.gov/radiance/book>). The problem is that you'll probably want to switch at some point from using illum's to just open holes as you have them once you get a certain number and it stops paying off in the calculation. With illum's, you can decrease -ab 3 to -ab 2 and get the same result.

-Greg

···

From: "Jelle Feringa / EZCT Architecture & Design Research" <[email protected]>
Date: June 9, 2005 3:56:46 AM PDT

Dear Greg,

I uploaded some images to: www.ezct.net/radiance/rpict_area_settings/
Currently I'm using the following rpict parameters:

rpict.exe -vf render.vf -ab 3 -ar 512 -ad 512 -ps 1 -as 512 -x 1500 -y 1500

which is pretty basic, but as you'll see in the last frame is fast and
artifact free, whereas there's little open area in the initial frame, which
of course leads to artifacts.

I'm rendering out a animation which shows a cube dissolving in space, each
frame cuts out a certain area of the box, slowly leaving it to dissolve.
I figure having the open area parameter drive the Radiance parameters would
be a good approach, wouldn't it?

Cheers,

Jelle.