[Radiance-general] RE: Modeling Question for Translucent Glass
Nikhil Kapur
building.simulation at gmail.com
Fri Jun 13 09:52:51 PDT 2008
I really appreciate the responses from all you folks.
Chris the trans panel was invisible in the illuminance run and showed up in
the Luminance run. Thanks for pointing that out.
Regards,
Nikhil
Chris I tried it both ways using with and without the -I command
I am using the window binaries and am running the simulation using ECOTECT's
Radiance Control Panel. The
2008/6/12 <radiance-general-request at radiance-online.org>:
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> Today's Topics:
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> 1. Re: oconv and rtrace_dc warnings for non-planar vertices
> (Thomas Bleicher)
> 2. Re: oconv and rtrace_dc warnings for non-planar vertices
> (Greg Ward)
> 3. Re: Modeling Question for Translucent Glass (Thomas Bleicher)
> 4. RE: Modeling Question for Translucent Glass (Christopher Rush)
> 5. Re: Modeling Question for Translucent Glass (Greg Ward)
>
>
> ---------- Forwarded message ----------
> From: Thomas Bleicher <tbleicher at arcor.de>
> To: Radiance general discussion <radiance-general at radiance-online.org>
> Date: Thu, 12 Jun 2008 20:16:05 +0100
> Subject: Re: [Radiance-general] oconv and rtrace_dc warnings for non-planar
> vertices
>
> On 11 Jun 2008, at 21:24, Ramana Koti wrote:
>
> oconv: warning - non-planar verterx for polygon "f_1719_0" (this happens
>> for 20 or so polygons)
>> rtrace_dc: warning - non-planar vertex for polygon "F_1636 (Can't see the
>> rest of it, this happens for probably the same polygons but not in the same
>> order)
>>
>> I used the SketchUp to Radiance su2rad plugin to export geometry from a
>> sketchup model and I had to start the simulation before DAYSIM refreshed
>> geometry display since it was taking too long to do that.
>>
>> How serious are these warnings and why are they occuring?
>>
>
> The export of polygons from Sketchup has only a limited accuracy. This
> results in some
> cases in polygons where one of the points is outside of the plane defined
> by the rest
> of the vertices. Radiance has a built in tolerance for these points but
> when that's exceeded
> the warning is generated and the vertex or the whole polygon ignored in the
> rendering.
> I'm not sure about the last part but maybe someone else knows better.
>
> Relevance: If the polygon is ignored and it is essential for the geometry
> (ie a wall of a room)
> then it is relevant. If it's just a tiny piece that doesn't do much for the
> lighting it's harmless.
>
> To avoid this problem export with the option 'triangulate'. This creates
> polygons with
> only 3 vertices. Much more polygons in the scene but no warnings.
>
> Regards,
> Thomas
>
>
>
>
>
>
> ---------- Forwarded message ----------
> From: Greg Ward <gregoryjward at gmail.com>
> To: Radiance general discussion <radiance-general at radiance-online.org>
> Date: Thu, 12 Jun 2008 14:40:22 -0700
> Subject: Re: [Radiance-general] oconv and rtrace_dc warnings for non-planar
> vertices
> The warnings don't indicate any action, and are only given by Radiance
> because cracks may appear between polygons due to the determination of an
> "average plane" that doesn't pass exactly through every point.
>
> -Greg
>
> From: Thomas Bleicher <tbleicher at arcor.de>
>> Date: June 12, 2008 12:16:05 PM PDT
>>
>> On 11 Jun 2008, at 21:24, Ramana Koti wrote:
>>
>> oconv: warning - non-planar verterx for polygon "f_1719_0" (this happens
>>> for 20 or so polygons)
>>> rtrace_dc: warning - non-planar vertex for polygon "F_1636 (Can't see the
>>> rest of it, this happens for probably the same polygons but not in the same
>>> order)
>>>
>>> I used the SketchUp to Radiance su2rad plugin to export geometry from a
>>> sketchup model and I had to start the simulation before DAYSIM refreshed
>>> geometry display since it was taking too long to do that.
>>>
>>> How serious are these warnings and why are they occuring?
>>>
>>
>> The export of polygons from Sketchup has only a limited accuracy. This
>> results in some
>> cases in polygons where one of the points is outside of the plane defined
>> by the rest
>> of the vertices. Radiance has a built in tolerance for these points but
>> when that's exceeded
>> the warning is generated and the vertex or the whole polygon ignored in
>> the rendering.
>> I'm not sure about the last part but maybe someone else knows better.
>>
>> Relevance: If the polygon is ignored and it is essential for the geometry
>> (ie a wall of a room)
>> then it is relevant. If it's just a tiny piece that doesn't do much for
>> the lighting it's harmless.
>>
>> To avoid this problem export with the option 'triangulate'. This creates
>> polygons with
>> only 3 vertices. Much more polygons in the scene but no warnings.
>>
>> Regards,
>> Thomas
>>
>
>
>
>
> ---------- Forwarded message ----------
> From: Thomas Bleicher <tbleicher at arcor.de>
> To: Radiance general discussion <radiance-general at radiance-online.org>
> Date: Thu, 12 Jun 2008 23:03:00 +0100
> Subject: Re: [Radiance-general] Modeling Question for Translucent Glass
>
> On 12 Jun 2008, at 17:50, Nikhil Kapur wrote:
>
> I am fairly new to Radiance and was trying to model a interior translucent
> glazing
>
>
> void trans translucent panel
>
> 0
>
> 0
>
> 7 1 1 1 0 0 0.5 0.2
>
> One obvious error is the name 'translucent panel'. Identifiers can not
> contain
> spaces so it should be 'translucent_panel' or something like that.
>
> The '1 1 1' looks odd to me. I don't think that's actually a physical
> material.
> I'd go for something like 0.8 for white.
>
> The second issue which I have not been able to figure out is how to show
> this trans material inside the space in the final rendering in Radiance as
> it is essentially invisible.
>
> Think about it:
> if it's 50% translucent it has to be visible (even glass with 50%
> transmission would
> show as a darker shade of the room behind it.) You're talking about 'white'
> so I assume
> that you do want some amount of scattering of the light. In fact, the
> material above
> scatters 80% of the light that passes, so it would definitely be visible.
>
> Just try a simple scene with a test cube and a bit of ground below and use
> the command 'objview' (Unix only) to see how the material works out.
>
> Regards,
> Thomas
>
>
> ---------- Forwarded message ----------
> From: "Christopher Rush" <Christopher.Rush at arup.com>
> To: "Radiance general discussion" <radiance-general at radiance-online.org>
> Date: Thu, 12 Jun 2008 18:16:22 -0400
> Subject: RE: [Radiance-general] Modeling Question for Translucent Glass
> A thought about rendering as "invisible" ..
>
> Nik, Is it invisible in any rendering, or only if you render an illuminance
> image with the -i option?
>
> ------------------------------
> *From:* radiance-general-bounces at radiance-online.org [mailto:
> radiance-general-bounces at radiance-online.org] *On Behalf Of *Thomas
> Bleicher
> *Sent:* Thursday, 12 June, 2008 6:03 PM
> *To:* Radiance general discussion
> *Subject:* Re: [Radiance-general] Modeling Question for Translucent Glass
>
>
> On 12 Jun 2008, at 17:50, Nikhil Kapur wrote:
>
> I am fairly new to Radiance and was trying to model a interior
> translucent glazing
>
>
> void trans translucent panel
>
> 0
>
> 0
>
> 7 1 1 1 0 0 0.5 0.2
>
> One obvious error is the name 'translucent panel'. Identifiers can not
> contain
> spaces so it should be 'translucent_panel' or something like that.
>
> The '1 1 1' looks odd to me. I don't think that's actually a physical
> material.
> I'd go for something like 0.8 for white.
>
> The second issue which I have not been able to figure out is how to show
> this trans material inside the space in the final rendering in Radiance as
> it is essentially invisible.
>
> Think about it:
> if it's 50% translucent it has to be visible (even glass with 50%
> transmission would
> show as a darker shade of the room behind it.) You're talking about 'white'
> so I assume
> that you do want some amount of scattering of the light. In fact, the
> material above
> scatters 80% of the light that passes, so it would definitely be visible.
>
> Just try a simple scene with a test cube and a bit of ground below and use
> the command 'objview' (Unix only) to see how the material works out.
>
> Regards,
> Thomas
>
> ____________________________________________________________
> Electronic mail messages entering and leaving Arup business
> systems are scanned for acceptability of content and viruses
>
>
>
> ---------- Forwarded message ----------
> From: Greg Ward <gregoryjward at gmail.com>
> To: "Nikhil Kapur" <nkapur at ctgenergetics.com>
> Date: Thu, 12 Jun 2008 15:35:38 -0700
> Subject: [Radiance-general] Re: Modeling Question for Translucent Glass
> Hi Nikhil,
>
> As Thomas said in his response, the material should show up in a normal
> rendering. The best way to model frit glass is to use the "glaze.csh"
> script that I created with funding from Visarc. For a single-pane glazing
> using a full covering of V-175 white frit, this script produces:
>
> ############################################
> # Glazing produced by Radiance glaze script
> # $Revision: 2.7 $
> # Material surface normal points to interior
> # Number of panes in system: 1
> # Exterior surface s1 type: clear glass
> # Interior surface s2 type: V-175 white frit
> # s2 coating coverage: 1
> # Exterior normal hemispherical reflectance: 0.33
> # Interior normal hemispherical reflectance: 0.59
> # Normal hemispherical transmittance: 0.21
> #
> void BRTDfunc glaze1_unnamed
> 10
> sr_frit_r sr_frit_g sr_frit_b
> st_frit_r st_frit_g st_frit_b
> 0 0 0
> glaze1.cal
> 0
> 11
> 0.59
> 0.59
> 0.59
> 0.256
> 0.253
> 0.251
> 0.21
> 0.21
> 0.21
> -1 1
>
> Try this for now, or run the script yourself to vary the parameters. If
> you can't run the script because you only have a Windows machine, then you
> may be stuck playing around with the "trans" material.
>
> -Greg
>
> From: "Nikhil Kapur" <nkapur at ctgenergetics.com>
>> Date: June 12, 2008 3:14:17 PM PDT
>> Hi Greg,
>>
>> I had a question for modeling in Radiance. I apologize for emailing to you
>> directly. I have posted it on the radiance forum today morning as well, but
>> had not seen any responses and I have a deadline to meet.
>>
>> Since I am fairly new to Radiance I was trying to model an interior
>> translucent glazing (possibly a frit on the glazing). I looked up the
>> archive posts for help but needed a little bit more guidance on the modeling
>> of the glazing. I am using ECOTECT for the basic geometry and ECOTECT's
>> Radiance Panel to interface with Radiance.
>>
>> I am modeling a white translucent glazing with about 50% transmittance
>> using the following parameters:
>>
>> void trans translucent panel
>>
>> 0
>>
>> 0
>>
>> 7 1 1 1 0 0 0.5 0.2
>>
>> I would like to know if I am correct in my assumptions or if there is some
>> other way to model a translucent / frit glass (any resources on the web that
>> I can look up)
>>
>> Additionally, I have not been able to figure how to show this trans
>> material inside the space in the final rendering in Radiance as it is
>> essentially invisible. I was reading up on the illum material type but could
>> not figure out how to apply it to this translucent glazing.
>>
>> Any help on this will be appreciated.
>>
>> Thanks.
>>
>> Nikhil Kapur
>>
>> CTG Energetics, Inc
>>
>> 9 4 9 . 4 2 8 . 6 2 7 1
>>
>
>
>
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