genklemsamp - surface orientation

Hi all,

I am trying to figure sampling window geometry where the normal is not parallel to the ground plane. So a sloped skylight for example. If I am passing the geometry for the glazing to genklemsamp, is all I need in addition, the normal for the surface? For example:

    genklemsamp -vd 1 0 1 sloped_window.rad > samples.dat

or do I need to specify view up?

Thanks,

-Jack

···

--
Jack de Valpine
President

Visarc Incorporated
www.visarc.com

channeling technology for superior design and construction

Hi Jack,

The view defaults for genklemsamp are the same as the rendering programs, except that it assumes a parallel view (-vtl). The view up vector will be +Z unless you specify otherwise. So long as it isn't parallel to your view direction, as in the case of a horizontal skylight, you don't need to specify it.

You will need to specify the interior normal direction using the kbin() function defined in klems_int.cal for your "view matrix" calculation. Just make sure these agree with what you give to genklemsamp.

Cheers,
-Greg

···

From: Jack de Valpine <[email protected]>
Date: March 29, 2013 2:06:33 PM PDT

Hi all,

I am trying to figure sampling window geometry where the normal is not parallel to the ground plane. So a sloped skylight for example. If I am passing the geometry for the glazing to genklemsamp, is all I need in addition, the normal for the surface? For example:
genklemsamp -vd 1 0 1 sloped_window.rad > samples.dat
or do I need to specify view up?

Thanks,

-Jack
--
Jack de Valpine
President

Visarc Incorporated
www.visarc.com

channeling technology for superior design and construction

Hello everyone,

Sorry to bring this topic back to live, but I have one doubt.

I thought the view-up was to tell Radiance the orientation of the BSDF
data... I mean, the "y" direction on the BSDF calculations. Is that ok?

In that case, if I put a skylight, my "view up" would be horizontal, even
if the view up of the scene is not....??? Does it make sense to set the
"view up" as 0 0 1 in the case that Jack is mentioning?

THANKS VERY MUCH

German

···

2013/3/29 Greg Ward <[email protected]>

Hi Jack,

The view defaults for genklemsamp are the same as the rendering programs,
except that it assumes a parallel view (-vtl). The view up vector will be
+Z unless you specify otherwise. So long as it isn't parallel to your view
direction, as in the case of a horizontal skylight, you don't need to
specify it.

You will need to specify the interior normal direction using the kbin()
function defined in klems_int.cal for your "view matrix" calculation. Just
make sure these agree with what you give to genklemsamp.

Cheers,
-Greg

*From: *Jack de Valpine <[email protected]>

*Date: *March 29, 2013 2:06:33 PM PDT

*
*

Hi all,

I am trying to figure sampling window geometry where the normal is not
parallel to the ground plane. So a sloped skylight for example. If I am
passing the geometry for the glazing to genklemsamp, is all I need in
addition, the normal for the surface? For example:

genklemsamp -vd 1 0 1 sloped_window.rad > samples.dat

or do I need to specify view up?

Thanks,

-Jack

--
Jack de Valpine
President

Visarc Incorporatedwww.visarc.com

channeling technology for superior design and construction

_______________________________________________
Radiance-general mailing list
[email protected]
http://www.radiance-online.org/mailman/listinfo/radiance-general

Hi German,

To orient the coordinates for genklemsamp, the view up vector
is essentially projected onto the plane normal to the view direction (or
BSDF surface normal). So if you have sloped skylights you can use the +Z
vector for view up, and the BSDF will be oriented so that the +Y direction
is uphill on the skylight.

However if your skylight is horizontal, than +Z is parallel to the view
direction (or BSDF surface normal) so as you suggest you need to provide a
non-vertical view up vector.

Andy

···

On Wed, Apr 3, 2013 at 7:24 AM, Germán Molina Larrain <[email protected]>wrote:

Hello everyone,

Sorry to bring this topic back to live, but I have one doubt.

I thought the view-up was to tell Radiance the orientation of the BSDF
data... I mean, the "y" direction on the BSDF calculations. Is that ok?

In that case, if I put a skylight, my "view up" would be horizontal, even
if the view up of the scene is not....??? Does it make sense to set the
"view up" as 0 0 1 in the case that Jack is mentioning?

THANKS VERY MUCH

German

2013/3/29 Greg Ward <[email protected]>

Hi Jack,

The view defaults for genklemsamp are the same as the rendering programs,
except that it assumes a parallel view (-vtl). The view up vector will be
+Z unless you specify otherwise. So long as it isn't parallel to your view
direction, as in the case of a horizontal skylight, you don't need to
specify it.

You will need to specify the interior normal direction using the kbin()
function defined in klems_int.cal for your "view matrix" calculation. Just
make sure these agree with what you give to genklemsamp.

Cheers,
-Greg

*From: *Jack de Valpine <[email protected]>

*Date: *March 29, 2013 2:06:33 PM PDT

*
*

Hi all,

I am trying to figure sampling window geometry where the normal is not
parallel to the ground plane. So a sloped skylight for example. If I am
passing the geometry for the glazing to genklemsamp, is all I need in
addition, the normal for the surface? For example:

genklemsamp -vd 1 0 1 sloped_window.rad > samples.dat

or do I need to specify view up?

Thanks,

-Jack

--
Jack de Valpine
President

Visarc Incorporatedwww.visarc.com

channeling technology for superior design and construction

_______________________________________________
Radiance-general mailing list
[email protected]
http://www.radiance-online.org/mailman/listinfo/radiance-general

_______________________________________________
Radiance-general mailing list
[email protected]
http://www.radiance-online.org/mailman/listinfo/radiance-general

Thanks Andrew, I didn't know about that projection... It may be very useful
in some cases.

THANKS VERY MUCH

German

···

2013/4/3 Andrew McNeil <[email protected]>

Hi German,

To orient the coordinates for genklemsamp, the view up vector
is essentially projected onto the plane normal to the view direction (or
BSDF surface normal). So if you have sloped skylights you can use the +Z
vector for view up, and the BSDF will be oriented so that the +Y direction
is uphill on the skylight.

However if your skylight is horizontal, than +Z is parallel to the view
direction (or BSDF surface normal) so as you suggest you need to provide a
non-vertical view up vector.

Andy

On Wed, Apr 3, 2013 at 7:24 AM, Germán Molina Larrain <[email protected]>wrote:

Hello everyone,

Sorry to bring this topic back to live, but I have one doubt.

I thought the view-up was to tell Radiance the orientation of the BSDF
data... I mean, the "y" direction on the BSDF calculations. Is that ok?

In that case, if I put a skylight, my "view up" would be horizontal, even
if the view up of the scene is not....??? Does it make sense to set the
"view up" as 0 0 1 in the case that Jack is mentioning?

THANKS VERY MUCH

German

2013/3/29 Greg Ward <[email protected]>

Hi Jack,

The view defaults for genklemsamp are the same as the rendering
programs, except that it assumes a parallel view (-vtl). The view up
vector will be +Z unless you specify otherwise. So long as it isn't
parallel to your view direction, as in the case of a horizontal skylight,
you don't need to specify it.

You will need to specify the interior normal direction using the kbin()
function defined in klems_int.cal for your "view matrix" calculation. Just
make sure these agree with what you give to genklemsamp.

Cheers,
-Greg

*From: *Jack de Valpine <[email protected]>

*Date: *March 29, 2013 2:06:33 PM PDT

*
*

Hi all,

I am trying to figure sampling window geometry where the normal is not
parallel to the ground plane. So a sloped skylight for example. If I am
passing the geometry for the glazing to genklemsamp, is all I need in
addition, the normal for the surface? For example:

genklemsamp -vd 1 0 1 sloped_window.rad > samples.dat

or do I need to specify view up?

Thanks,

-Jack

--
Jack de Valpine
President

Visarc Incorporatedwww.visarc.com

channeling technology for superior design and construction

_______________________________________________
Radiance-general mailing list
[email protected]
http://www.radiance-online.org/mailman/listinfo/radiance-general

_______________________________________________
Radiance-general mailing list
[email protected]
http://www.radiance-online.org/mailman/listinfo/radiance-general

_______________________________________________
Radiance-general mailing list
[email protected]
http://www.radiance-online.org/mailman/listinfo/radiance-general

Hi Greg and All,

In brief follow-up to this, I want to sanity check myself. For the 3 phase method:

  * vmx - for rcontrib klems_int.cal needs the normal from the glazing
    surface pointing to the interior, eg <0,1,0> for a south facing window
  * dmx - for genklemsamp the view direction is the normal direction
    pointing outside, the opposite of what is used for vmx, eg <0,-1,0>
    for a south facing window

Lastly, as long as a glazing surface is not facing straight up, that is a skylight parallel to the ground plane, then then an up direction of <0,0,1> can be used.

Thanks,

-Jack

···

--
Jack de Valpine
President

Visarc Incorporated
www.visarc.com

channeling technology for superior design and construction

On 3/29/2013 6:15 PM, Greg Ward wrote:

Hi Jack,

The view defaults for genklemsamp are the same as the rendering programs, except that it assumes a parallel view (-vtl). The view up vector will be +Z unless you specify otherwise. So long as it isn't parallel to your view direction, as in the case of a horizontal skylight, you don't need to specify it.

You will need to specify the interior normal direction using the kbin() function defined in klems_int.cal for your "view matrix" calculation. Just make sure these agree with what you give to genklemsamp.

Cheers,
-Greg

*From: *Jack de Valpine <[email protected] <mailto:[email protected]>>

*Date: *March 29, 2013 2:06:33 PM PDT

*

Hi all,

I am trying to figure sampling window geometry where the normal is not parallel to the ground plane. So a sloped skylight for example. If I am passing the geometry for the glazing to genklemsamp, is all I need in addition, the normal for the surface? For example:

    genklemsamp -vd 1 0 1 sloped_window.rad > samples.dat

or do I need to specify view up?

Thanks,

-Jack
--
Jack de Valpine
President

Visarc Incorporated
www.visarc.com

channeling technology for superior design and construction

_______________________________________________
Radiance-general mailing list
[email protected]
http://www.radiance-online.org/mailman/listinfo/radiance-general

Jack,

What you say about the VMX and DMX are correct.

For the up direction, if the window is not a skylight, the 0 0 1 can be
used; but it has to be noted that that direction will be projected over the
plane of the window, so, in reality, it will not be 0 0 1 anymore.

German

Hi German,

Great! Thanks for the sanity check.

-Jack

···

--
Jack de Valpine
President

Visarc Incorporated
www.visarc.com

channeling technology for superior design and construction

On 6/5/2013 4:04 PM, Germán Molina Larrain wrote:

Jack,

What you say about the VMX and DMX are correct.

For the up direction, if the window is not a skylight, the 0 0 1 can be used; but it has to be noted that that direction will be projected over the plane of the window, so, in reality, it will not be 0 0 1 anymore.

German

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Radiance-general mailing list
[email protected]
http://www.radiance-online.org/mailman/listinfo/radiance-general