# Antimatter

Dear All,

It has been a real pleasure to have the chance to be at the radiance
workshop in Cambridge and to meet all the great guys there and to listen
to so many inspiring presentations (btw, really looking forward to see
them on line!)

Now back to the office and again fighting with day to day issues. I am
trying to model a series of openings in a screen using antimatter and I
am getting really confused.
The screen is modelled as a single surface intersected by a number of
cubes. As in the antimatter description I read:
"The viewpoint must be outside all volumes concerned for a correct
rendering." I assume that means that the camera should not be inside one
of the cubes and that (I guess) the cube normals should point outward.
Done that, I am able to see through the cubes but I do not see the
pattern of light coming through the antimatter holes, I just have a big
solid shadow...

Is that how it is supposed to behave? Does anybody have any clue about
what I am doing wrong?

Thanks in advance,
Best,

Giovanni

Hi Giovanni,

Which version of Radiance are you using? There was a bug in 3.8 relating to antimatter and shadows, which was (hopefully) fixed in version 3.9.

-Greg

···

From: "Giovanni Betti" <[email protected]>
Date: October 30, 2009 9:40:22 AM PDT

Dear All,

It has been a real pleasure to have the chance to be at the radiance
workshop in Cambridge and to meet all the great guys there and to listen
to so many inspiring presentations (btw, really looking forward to see
them on line!)

Now back to the office and again fighting with day to day issues. I am
trying to model a series of openings in a screen using antimatter and I
am getting really confused.
The screen is modelled as a single surface intersected by a number of
cubes. As in the antimatter description I read:
"The viewpoint must be outside all volumes concerned for a correct
rendering." I assume that means that the camera should not be inside one
of the cubes and that (I guess) the cube normals should point outward.
Done that, I am able to see through the cubes but I do not see the
pattern of light coming through the antimatter holes, I just have a big
solid shadow...

Is that how it is supposed to behave? Does anybody have any clue about
what I am doing wrong?

Thanks in advance,
Best,

Giovanni

Hi Giovanni,

It was great to meet you at the workshop. Thanks for making the trip over to the states!

It has been awhile since I did anything with antimatter but here is an example that should work:

void plastic white
0
5 1 1 1 0 0

void plastic red
0
5 1 0 0 0 0

void antimatter am
2 red white
0

!genbox white wall 10 .1 10

!genbox am holes 1 1 1 | xform -t -.5 -.5 -.5 -t 1 0 5 -a 5 -t 2 0 0

This will make five holes in the "wall" geometry, where the holes are cut will be red.

The main trick here is understanding the antimatter material definition

void antimatter <name>
2 <mod1> <mod2>
0

where I think of it as "make a hole using material <mod1> in material <mod2>." If you do not want there to be any material where the hole is cut then mod1 can be void.

At first I was thinking that this only works on "volumes" rather than surfaces. But a quick test shows that it does work on surfaces as well:

white polygon wall
0
12
0 0 0
10 0 0
10 0 10
0 0 10

!genbox am holes 1 1 1 | xform -t -.5 -.5 -.5 -t 1 0 5 -a 5 -t 2 0 0

NOTE however that if you want to punch holes in planar surfaces then <mod1> needs to be "void" in the antimatter definition.

Hope this helps,

-Jack de Valpine

···

--
# Jack de Valpine
# president
#
# visarc incorporated
# http://www.visarc.com
#
# channeling technology for superior design and construction

Giovanni Betti wrote:

Dear All,

It has been a real pleasure to have the chance to be at the radiance
workshop in Cambridge and to meet all the great guys there and to listen
to so many inspiring presentations (btw, really looking forward to see
them on line!)

Now back to the office and again fighting with day to day issues. I am
trying to model a series of openings in a screen using antimatter and I
am getting really confused.
The screen is modelled as a single surface intersected by a number of
cubes. As in the antimatter description I read:
"The viewpoint must be outside all volumes concerned for a correct
rendering." I assume that means that the camera should not be inside one
of the cubes and that (I guess) the cube normals should point outward. Done that, I am able to see through the cubes but I do not see the
pattern of light coming through the antimatter holes, I just have a big
solid shadow...

Is that how it is supposed to behave? Does anybody have any clue about
what I am doing wrong?

Thanks in advance,
Best,

Giovanni

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

As a test, I did this in sketchup, and got curious results...
The light goes through, but only on the edge. All the grey boxes are antimatter, cutting through the wall.

my materials:
## material conversion from Sketchup rgb color
void plastic sketchup_default_material
0
0
5 0.1400 0.3400 0.3400 0.000 0.000

void antimatter cutter
2 void sketchup_default_material
0
0

Rob Fitz

···

-----Original Message-----
From: [email protected] on behalf of Giovanni Betti
Sent: Fri 10/30/2009 9:40 AM
To: Radiance general discussion
Subject: [Radiance-general] Antimatter

Dear All,

It has been a real pleasure to have the chance to be at the radiance
workshop in Cambridge and to meet all the great guys there and to listen
to so many inspiring presentations (btw, really looking forward to see
them on line!)

Now back to the office and again fighting with day to day issues. I am
trying to model a series of openings in a screen using antimatter and I
am getting really confused.
The screen is modelled as a single surface intersected by a number of
cubes. As in the antimatter description I read:
"The viewpoint must be outside all volumes concerned for a correct
rendering." I assume that means that the camera should not be inside one
of the cubes and that (I guess) the cube normals should point outward.
Done that, I am able to see through the cubes but I do not see the
pattern of light coming through the antimatter holes, I just have a big
solid shadow...

Is that how it is supposed to behave? Does anybody have any clue about
what I am doing wrong?

Thanks in advance,
Best,

Giovanni

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

Hi Rob,

If you do the following it should work with a material at the cut:

void antimatter cutter
2 sketchup_default_material sketchup_default_material
0

-Jack

···

--
# Jack de Valpine
# president
#
# visarc incorporated
# http://www.visarc.com
#
# channeling technology for superior design and construction

Fitzsimmons, Rob wrote:

As a test, I did this in sketchup, and got curious results...
The light goes through, but only on the edge. All the grey boxes are antimatter, cutting through the wall.

my materials:
## material conversion from Sketchup rgb color
void plastic sketchup_default_material
0
5 0.1400 0.3400 0.3400 0.000 0.000

void antimatter cutter
2 void sketchup_default_material
0

Rob Fitz

-----Original Message-----
From: ra[email protected] on behalf of Giovanni Betti
Sent: Fri 10/30/2009 9:40 AM
To: Radiance general discussion
Subject: [Radiance-general] Antimatter

Dear All,

It has been a real pleasure to have the chance to be at the radiance
workshop in Cambridge and to meet all the great guys there and to listen
to so many inspiring presentations (btw, really looking forward to see
them on line!)

Now back to the office and again fighting with day to day issues. I am
trying to model a series of openings in a screen using antimatter and I
am getting really confused.
The screen is modelled as a single surface intersected by a number of
cubes. As in the antimatter description I read:
"The viewpoint must be outside all volumes concerned for a correct
rendering." I assume that means that the camera should not be inside one
of the cubes and that (I guess) the cube normals should point outward.
Done that, I am able to see through the cubes but I do not see the
pattern of light coming through the antimatter holes, I just have a big
solid shadow...

Is that how it is supposed to behave? Does anybody have any clue about
what I am doing wrong?

Thanks in advance,
Best,

Giovanni

_______________________________________________
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 Rob,

Looks like I missed the point of the question. I see what you mean about the shadow.....

-Jack

Jack de Valpine wrote:

···

Hi Rob,

If you do the following it should work with a material at the cut:

void antimatter cutter
2 sketchup_default_material sketchup_default_material
0

-Jack

--
# Jack de Valpine
# president
#
# visarc incorporated
# http://www.visarc.com
#
# channeling technology for superior design and construction

Fitzsimmons, Rob wrote:

As a test, I did this in sketchup, and got curious results...
The light goes through, but only on the edge. All the grey boxes are antimatter, cutting through the wall.

my materials:
## material conversion from Sketchup rgb color
void plastic sketchup_default_material
0
5 0.1400 0.3400 0.3400 0.000 0.000

void antimatter cutter
2 void sketchup_default_material
0

Rob Fitz

-----Original Message-----
From: [email protected] on behalf of Giovanni Betti
Sent: Fri 10/30/2009 9:40 AM
To: Radiance general discussion
Subject: [Radiance-general] Antimatter

Dear All,

It has been a real pleasure to have the chance to be at the radiance
workshop in Cambridge and to meet all the great guys there and to listen
to so many inspiring presentations (btw, really looking forward to see
them on line!)

Now back to the office and again fighting with day to day issues. I am
trying to model a series of openings in a screen using antimatter and I
am getting really confused.
The screen is modelled as a single surface intersected by a number of
cubes. As in the antimatter description I read:
"The viewpoint must be outside all volumes concerned for a correct
rendering." I assume that means that the camera should not be inside one
of the cubes and that (I guess) the cube normals should point outward.
Done that, I am able to see through the cubes but I do not see the
pattern of light coming through the antimatter holes, I just have a big
solid shadow...

Is that how it is supposed to behave? Does anybody have any clue about
what I am doing wrong?

Thanks in advance,
Best,

Giovanni

_______________________________________________
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

--
# Jack de Valpine
# president
#
# visarc incorporated
# http://www.visarc.com
#
# channeling technology for superior design and construction

Thanks All,

I think it might be because of the version a(I definitely use an older
version of Radiance)

I have pretty much the same results as Rob.

I'll try on a new version on Monday, I guess...

Best,

Giovanni

···

________________________________

From: [email protected]
[mailto:[email protected]] On Behalf Of Jack
de Valpine
Sent: 30 October 2009 17:38
To: Radiance general discussion
Subject: Re: [Radiance-general] Antimatter

Hi Rob,

Looks like I missed the point of the question. I see what you mean about
the shadow.....

-Jack

Jack de Valpine wrote:

Hi Rob,

If you do the following it should work with a material at the cut:

void antimatter cutter
2 sketchup_default_material sketchup_default_material
0
0

-Jack

--
# Jack de Valpine
# president
#
# visarc incorporated
# http://www.visarc.com
#
# channeling technology for superior design and construction

Fitzsimmons, Rob wrote:

As a test, I did this in sketchup, and got curious results...
The light goes through, but only on the edge. All the grey boxes are
antimatter, cutting through the wall.

my materials:
## material conversion from Sketchup rgb color
void plastic sketchup_default_material
0
0
5 0.1400 0.3400 0.3400 0.000 0.000

void antimatter cutter
2 void sketchup_default_material
0
0

Rob Fitz

-----Original Message-----
From: [email protected] on behalf of Giovanni
Betti
Sent: Fri 10/30/2009 9:40 AM
To: Radiance general discussion
Subject: [Radiance-general] Antimatter

Dear All,

It has been a real pleasure to have the chance to be at the radiance
workshop in Cambridge and to meet all the great guys there and to listen
to so many inspiring presentations (btw, really looking forward to see
them on line!)

Now back to the office and again fighting with day to day issues. I am
trying to model a series of openings in a screen using antimatter and I
am getting really confused.
The screen is modelled as a single surface intersected by a number of
cubes. As in the antimatter description I read:
"The viewpoint must be outside all volumes concerned for a correct
rendering." I assume that means that the camera should not be inside one
of the cubes and that (I guess) the cube normals should point outward.
Done that, I am able to see through the cubes but I do not see the
pattern of light coming through the antimatter holes, I just have a big
solid shadow...

Is that how it is supposed to behave? Does anybody have any clue about
what I am doing wrong?

Thanks in advance,
Best,

Giovanni

_______________________________________________
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

--
# Jack de Valpine
# president
#
# visarc incorporated
# http://www.visarc.com
#
# channeling technology for superior design and construction

Hi Rob,

I'm not able to reproduce this error with the latest version of Radiance. What version are you running? Is anyone getting my e-mails?

Jack's example runs fine, and if you add a floor:

void plastic gray
0
5 .2 .2 .2 0 0

!genbox gray floor 10 10 .1 | xform -t 0 0 -.1001

...you get to see the shadows through the windows. I also tried using "void" instead of "red" as the first antimatter modifier and that works, as does making the wall infinitely thin (single surface), so I think you must be running version 3.8 or your cut-out surfaces are coincident or something...

The thing that doesn't work is using a non-void material as the first antimatter argument to cut a hole in a single-surface wall.

Cheers,
-Greg

···

From: "Fitzsimmons, Rob" <[email protected]>
Date: October 30, 2009 10:23:51 AM PDT

As a test, I did this in sketchup, and got curious results...
The light goes through, but only on the edge. All the grey boxes are antimatter, cutting through the wall.

my materials:
## material conversion from Sketchup rgb color
void plastic sketchup_default_material
0
5 0.1400 0.3400 0.3400 0.000 0.000

void antimatter cutter
2 void sketchup_default_material
0

Rob Fitz

Hi Greg,

Your emails are coming through.

A floor does help doesn't it.....

For reference, I am running 3.9

-Jack

Greg Ward wrote:

···

Hi Rob,

I'm not able to reproduce this error with the latest version of Radiance. What version are you running? Is anyone getting my e-mails?

Jack's example runs fine, and if you add a floor:

void plastic gray
0
5 .2 .2 .2 0 0

!genbox gray floor 10 10 .1 | xform -t 0 0 -.1001

...you get to see the shadows through the windows. I also tried using "void" instead of "red" as the first antimatter modifier and that works, as does making the wall infinitely thin (single surface), so I think you must be running version 3.8 or your cut-out surfaces are coincident or something...

The thing that doesn't work is using a non-void material as the first antimatter argument to cut a hole in a single-surface wall.

Cheers,
-Greg

*From: *"Fitzsimmons, Rob" <[email protected] <mailto:[email protected]>>

*Date: *October 30, 2009 10:23:51 AM PDT

*

As a test, I did this in sketchup, and got curious results...
The light goes through, but only on the edge. All the grey boxes are antimatter, cutting through the wall.

my materials:
## material conversion from Sketchup rgb color
void plastic sketchup_default_material
0
5 0.1400 0.3400 0.3400 0.000 0.000

void antimatter cutter
2 void sketchup_default_material
0

Rob Fitz

------------------------------------------------------------------------

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

--
# Jack de Valpine
# president
#
# visarc incorporated
# http://www.visarc.com
#
# channeling technology for superior design and construction