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2021-07-02 11:49:58 -0600 marked best answer How to generate point-in-time sky-vectors for sun-coefficient step in five-phase method

The annual sky-matrix for the sun disk can be generated using (e.g., from here):

gendaymtx -m 6 -5 0.533 -of assets/NYC.wea > skyVectors/NYCd6.smx

However, if I only want to generate the sky-vector for a certain point in time, what should I use?

I tried:

gensky 3 20 10:30EDT -m 75 -o 73.96 -a 40.78 | genskyvec -m 6 -5 0.533 > NYC_CIE_sun.vec

but got an error:

Unexpected command-line argument: 0.533

Can I simply do

gensky 3 20 10:30EDT -m 75 -o 73.96 -a 40.78 | genskyvec -m 6 -d > NYC_CIE_sun.vec

? In this case, will the absence of the sun disk size '-0.533' information post any problem?

2021-06-30 12:54:49 -0600 asked a question How to generate point-in-time sky-vectors for sun-coefficient step in five-phase method

How to generate point-in-time sky-vectors for sun-coefficient step in five-phase method The annual sky-matrix for the su

2021-06-29 14:54:58 -0600 commented answer What is the "up" direction defined by -u for the sample hemisphere of the rfluxmtx program

I see. The 'up' direction is the zero-azimuth (which is North) direction of the hemisphere, right? In this case, it make

2021-06-29 14:50:33 -0600 marked best answer What is the "up" direction defined by -u for the sample hemisphere of the rfluxmtx program

In the tutorial Daylighting Simulations with Radiance using Matrix-based Methods (pp. 42), the "view-up" vector of the rfluxmtx hemispherical sampling is set to +Y direction, as in the figure below.

To my understanding, the window of the room model is facing the negative Y direction, which is the "south" direction in Radiance. Then, why is the sampling hemisphere taken to the positive Y direction here? In other words, shouldn't the sampling rays be shot into the negative Y directions to get the daylight matrix?

How to understand the definition of the "view-up" vector?

.

2021-06-29 14:50:29 -0600 commented answer What is the "up" direction defined by -u for the sample hemisphere of the rfluxmtx program

I see. The 'up' direction is the zero-azimuth (which is North) direction of the hemisphere, right? In this case, it make

2021-06-29 13:52:05 -0600 commented answer What is the "up" direction defined by -u for the sample hemisphere of the rfluxmtx program

Thank you. Howeve, I am still confused about the -u option. For example, if I have three buildings, one with the windo

2021-06-29 00:34:36 -0600 edited question What is the "up" direction defined by -u for the sample hemisphere of the rfluxmtx program

What is the "up" direction defined by -u for the sample hemisphere of the rfluxmtx program In the tutorial Daylighting S

2021-06-29 00:33:55 -0600 edited question What is the "up" direction defined by -u for the sample hemisphere of the rfluxmtx program

What is the "up" direction defined by -u for the sample hemisphere of the rfluxmtx program In the tutorial Daylighting S

2021-06-29 00:32:24 -0600 received badge  Editor (source)
2021-06-29 00:32:24 -0600 edited question What is the "up" direction defined by -u for the sample hemisphere of the rfluxmtx program

What is the "up" direction defined by -u for the sample hemisphere of the rfluxmtx program In the tutorial Daylighting S

2021-06-29 00:29:22 -0600 asked a question What is the "up" direction defined by -u for the sample hemisphere of the rfluxmtx program

What is the "up" direction defined by -u for the sample hemisphere of the rfluxmtx program In the tutorial Daylighting S

2021-06-14 20:56:08 -0600 commented answer How does the Radiance treat path termination when pathtracing diffuse reflections?

Thank you. It now makes sense as -ab is a hard limit on the diffusive bounces. That's probably the reason why setting -a

2021-06-14 20:51:35 -0600 commented answer How does the Radiance treat path termination when pathtracing diffuse reflections?

Thank you. It now makes sense as -ab is a hard limit on the diffusive bounces. That's probably the reason why setting -a

2021-06-14 20:35:37 -0600 marked best answer How does the Radiance treat path termination when pathtracing diffuse reflections?

In Chap. 12 of Rendering with Radiance by @GregWard and Shakespeare, it is reported that a constant ambient approximation is used when the -ab number of bounces is reached in the pathtracing process.

Is this still the way Radiance deals with path termination now?

In the source code file ambient.c line 360-380, I do see some code that does constant ambient approximation. However, in the raytrace.c line 119-134, I see that the unbiased Russian Roulette is used.

I would like to confirm that for the functions like rcontrib and rfluxmtx, we are actually using Russian Roulette algorithm, right? In this case, the result should be unbiased no matter what -ab, -av or -aw parameter is given, right? In In Chap. 6.4.2 of Rendering with Radiance, the author "expect(s) the prediction for -ab 5 to be greater than those for -ab 1"; this in theory should not be the case for the tracer with Russian Roulette, right?

2021-06-14 13:34:30 -0600 asked a question How does the Radiance treat path termination when pathtracing diffuse reflections?

How does the Radiance treat path termination when pathtracing diffuse reflections? In Chap. 12 of Rendering with Radianc

2021-06-14 13:34:17 -0600 asked a question How does the Radiance treat path termination when pathtracing diffuse reflections?

How does the Radiance treat path termination when pathtracing diffuse reflections? In Chap. 12 of Rendering with Radianc

2021-06-14 13:34:04 -0600 asked a question How does the Radiance treat path termination when pathtracing diffuse reflections?

How does the Radiance treat path termination when pathtracing diffuse reflections? In Chap. 12 of Rendering with Radianc

2021-06-14 11:10:47 -0600 marked best answer Generating view matrices for multiple glazing apertures in Radiance?

I want to generate view matrices for each of the 6 separate windows in a room with rfluxmtx. I wonder what is the best practice to do so?

Should I put the window I'm interested in in a "GlazingVmtx.rad" file, run someting like

rfluxmtx -v -I+ -ab 4 -ad 5000 -lw 0.0002 -n 16 -y 100 - objects/GlazingVmtx.rad -i octrees/room3ph.oct < points.txt > matrices/vmtx/v.mtx

, and include the information of other windows in the octree file?

Or, can I put the information of all the windows in one rad file (for example, GlazingVmtx.rad), but only set the window I am interested in as a glow type?

Thanks in advance.

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2021-01-07 12:03:58 -0600 answered a question Generating view matrices for multiple glazing apertures in Radiance?

I found that Section 7.4 of Daylighting Simulations with Radiance using Matrix-based Methods gave a good example of what

2021-01-05 09:32:44 -0600 received badge  Student (source)
2021-01-05 09:32:27 -0600 asked a question Generating view matrices for multiple glazing apertures in Radiance?

Generating view matrices for multiple glazing apertures in Radiance? I want to generate view matrices for each of the 6