Dear list,

I have question that I hope you'll help get my head around.

I want to calculate the overall illuminance on a point in space that is,

regardless of directionality.

I have made some simplified 2d sketches for clarity.

As I understand a radiance sensor point in rtrace will have cosine

related sensitivity (image01)

If I am to place two coincident with opposing normals (image2) I'll miss

on contributions from the sides.

Rotating the normals by 90 degrees at a time (figure 3) and summing

contributions might not work either because will overestimate diagonal

contributions (figure 4 ).

So I'm not getting too much closer to the solution...

Is there something that I am missing here?

Any light on this will be appreciated,

Best,

Giovanni Betti

Hi Betti,

I think you can refer to Greg's answer to my question "Spherical sensor."

in Vol 94, Issue 11.

Good luck!

Minki

## ···

Date: Tue, 8 May 2012 12:42:03 +0100

From: "Giovanni Betti" <gbetti@fosterandpartners.com>

To: "Radiance general discussion"

<radiance-general@radiance-online.org>

Subject: [Radiance-general] integral of radiation in one point

Message-ID:

<6F5225D6E15F954BB4E58EC25F6736C308CFCE7D@corp3005.CORPORATE.

FOSTER.NETWORK>

Content-Type: text/plain; charset="us-ascii"

Dear list,

I have question that I hope you'll help get my head around.

I want to calculate the overall illuminance on a point in space that is,

regardless of directionality.

I have made some simplified 2d sketches for clarity.

As I understand a radiance sensor point in rtrace will have cosine

related sensitivity (image01)

If I am to place two coincident with opposing normals (image2) I'll miss

on contributions from the sides.

Rotating the normals by 90 degrees at a time (figure 3) and summing

contributions might not work either because will overestimate diagonal

contributions (figure 4 ).

So I'm not getting too much closer to the solution...

Is there something that I am missing here?

Any light on this will be appreciated,

Best,

Giovanni Betti