New stereographic fisheye view

radiance-general
1

Dear all,

Greg was kind enough to leave this announcement to me, since it was me
who has been giving him a hard time over it. Thanks for implementing
this, Greg!

So here we go:

I have the honor to announce a new fisheye view type for Radiance. It
is called the 'stereographic' or 'planispheric' projection. It is
particularly useful for sun path diagrams, as commonly used in
daylighting and overshadowing studies. Yes, it's true: no more messin'
about with .cal files--it's a native implementation. The option to
rvu/rpict/trace is -vts.

I've put together a little comparison of the three fisheye views:
http://luminance.londonmet.ac.uk/pickup/projections.pdf
This will eventually be merged into the Advanced Tutorial, but I don't
have the time for this right now.

If you feel like doing a little exercise with pen and paper (like our
students do), get a sun path diagram from here:
http://luxal.eu/resources/daylighting/sunpath.shtml,

and follow Andrew's the instructions on the SquareOne web site:
http://squ1.org/wiki/Sun-Path/Overshadowing

Good projections to you all

Axel

2

Axel Jacobs wrote:

I have the honor to announce a new fisheye view type for Radiance.

Thanks Axel, thanks Greg!

3

Hey Axel,

Very kewl new fisheye feature and even kewler website with sunpath and shading diagrams. Thank you.

Can you please explain how the "planospheric" fisheye projecting differs from the "-vta" angular fisheye project with "-vh 180"?

Thanks,
-Chas

···

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Message: 1
Date: Sun, 16 Mar 2008 22:33:23 +0000
From: "Axel Jacobs" <[email protected]>
Subject: [Radiance-general] New stereographic fisheye view
To: [email protected]
Message-ID:
    <[email protected]>
Content-Type: text/plain; charset=ISO-8859-1

Dear all,

Greg was kind enough to leave this announcement to me, since it was me
who has been giving him a hard time over it. Thanks for implementing
this, Greg!

So here we go:

I have the honor to announce a new fisheye view type for Radiance. It
is called the 'stereographic' or 'planispheric' projection. It is
particularly useful for sun path diagrams, as commonly used in
daylighting and overshadowing studies. Yes, it's true: no more messin'
about with .cal files--it's a native implementation. The option to
rvu/rpict/trace is -vts.

I've put together a little comparison of the three fisheye views:
http://luminance.londonmet.ac.uk/pickup/projections.pdf
This will eventually be merged into the Advanced Tutorial, but I don't
have the time for this right now.

If you feel like doing a little exercise with pen and paper (like our
students do), get a sun path diagram from here:
http://luxal.eu/resources/daylighting/sunpath.shtml,

and follow Andrew's the instructions on the SquareOne web site:
http://squ1.org/wiki/Sun-Path/Overshadowing

Good projections to you all

Axel

4

Hi Chas,

Can you please explain how the "planospheric" fisheye projecting
differs from the "-vta" angular fisheye project with "-vh 180"?

Hmm, I thought I'd done that in the PDF. Typically, all fisheye
projections are used with a -vh and -vv of 180. The difference is the
projection of the hemisphere onto a flat surface. Let me know where
the PDF needs some more clarifications.

Axel

5

Axel,

Just out of curiosity, in your projections.pdf document, the fish eye views show a scene that is mirrored on the top and bottom of the image. Why is this? If the view is looking straight up, I would think there would only be one building, one arch, one fountain, etc.. Also, the bottom of the image is darker than the top. Can you explain?

Thanks

Mark

6

Mark de la Fuente wrote:

Axel,
Just out of curiosity, in your projections.pdf document, the fish eye views show a scene that is mirrored on the top and bottom of the image. Why is this? If the view is looking straight up, I would think there would only be one building, one arch, one fountain, etc.. Also, the bottom of the image is darker than the top. Can you explain?

The lower scene is a reflection in the window glazing.

- Rob