When I created direct-only sky-matrix and sun-matrix of Hong Kong region by using commands "epw2wea" and "gendaymtx", the results seemed weird. The data of .smx file I rendered almost were null, so was the data of New York City . I had no ideas about its correctness. Anyone could help me out of confusion?
#Generate a direct-only sky-matrix for the sun coefficient calculation. #epw2wea weather/CHN_Hong.Kong.SAR.450070_CityUHK.epw weather/HK.wea #gendaymtx -m 1 -d weather/HK.wea > skyVectors/HKd.smx
#Generate a sun-matrix for the sun coefficient calculation. #epw2wea weather/CHN_Hong.Kong.SAR.450070_CityUHK.epw weather/HK.wea #gendaymtx -m 2 -5 0.533 -d weather/HK.wea > skyVectors/HKsun.smx
If by null you are implying zeros, then the generated files are fine. Your first gendaymtx command (-m 1 -d) will generate a sky matrix that is almost entirely zeros except for radiation values in 3-4 patches per hour during day-time. The second gendaymtx command (-m 2 -5 0.533 -d) will generate a file that contains radiation values only in a single patch per hour. If the direct-normal radiation data for a particular hour is zero, then the radiation values in all the patches for that hour in direct-sky matrix and sun-matrix will be zero as well.
Sarith
···
On 11/26/2017 08:26 PM, Wang Clarence wrote:
Dear all,
When I created direct-only sky-matrix and sun-matrix of Hong Kong region by using commands "epw2wea" and "gendaymtx", the results seemed weird. The data of .smx file I rendered almost were null, so was the data of New York City . I had no ideas about its correctness. Anyone could help me out of confusion?
#Generate a direct-only sky-matrix for the sun coefficient calculation. #epw2wea weather/CHN_Hong.Kong.SAR.450070_CityUHK.epw weather/HK.wea #gendaymtx -m 1 -d weather/HK.wea > skyVectors/HKd.smx
#Generate a sun-matrix for the sun coefficient calculation. #epw2wea weather/CHN_Hong.Kong.SAR.450070_CityUHK.epw weather/HK.wea #gendaymtx -m 2 -5 0.533 -d weather/HK.wea > skyVectors/HKsun.smx
It seems that the .smx files are fine. But there is another question.
When I combine the sun-matrix smx file with cds.mtx for direct sun coefficient simulation , which is the third part of the five-phase methods, the final data of cds.ill will be very small. Besides, since we use the data rendered by executing three phase method minus the data of direct solar part and plus the direct sun coefficient for rendering data of five phase method, the data of some measure points which are close to the window rendering by five phase will be twice or three times lower than that by three phase.
So what is the actual difference of data between three phase and five phase? Are the data rendering by five phase definitely similar to that by three phase?
Thanks,
Clarence
···
________________________________
发件人: Sarith Subramaniam <[email protected]>
发送时间: 2017年11月27日 5:50
收件人: Radiance general discussion
主题: Re: [Radiance-general] Generate sky-matrix by using TMY weather data
Hi Clarence,
If by null you are implying zeros, then the generated files are fine. Your first gendaymtx command ( -m 1 -d) will generate a sky matrix that is almost entirely zeros except for radiation values in 3-4 patches per hour during day-time. The second gendaymtx command (-m 2 -5 0.533 -d) will generate a file that contains radiation values only in a single patch per hour. If the direct-normal radiation data for a particular hour is zero, then the radiation values in all the patches for that hour in direct-sky matrix and sun-matrix will be zero as well.
Sarith
On 11/26/2017 08:26 PM, Wang Clarence wrote:
Dear all,
When I created direct-only sky-matrix and sun-matrix of Hong Kong region by using commands "epw2wea" and "gendaymtx", the results seemed weird. The data of .smx file I rendered almost were null, so was the data of New York City . I had no ideas about its correctness. Anyone could help me out of confusion?
#Generate a direct-only sky-matrix for the sun coefficient calculation. #epw2wea weather/CHN_Hong.Kong.SAR.450070_CityUHK.epw weather/HK.wea #gendaymtx -m 1 -d weather/HK.wea > skyVectors/HKd.smx
#Generate a sun-matrix for the sun coefficient calculation. #epw2wea weather/CHN_Hong.Kong.SAR.450070_CityUHK.epw weather/HK.wea #gendaymtx -m 2 -5 0.533 -d weather/HK.wea > skyVectors/HKsun.smx
I am not sure if I completely understood your question, but I think I can
help a bit understand what changed between 3 and 5 phases.
The three-phase method factorizes the DC matrix into three matrices ( DC =
VxTxD ), where T is the BSDF of a shading device. This helps changing T
without having to re-ray-trace, which is the slow process we want to avoid.
Despite being fast, the Daylight Matrix (the D part in VTD) assumes the
sun to be spread in three or four patches of the sky (thus, Sarith's
comment regarding most values exept 3-4 being zeros for each hour), which
is unrealistic. The sun is not diffuse and big, but direct and small (0.533
degrees, which explains the "-5 0.533" part on the gendaymtx command),
which is why you substract this "big diffuse sun" and replace it by a
"small direct" sun.
It seems that the .smx files are fine. But there is another question.
When I combine the sun-matrix smx file with cds.mtx for direct sun
coefficient simulation , which is the third part of the five-phase methods,
the final data of cds.ill will be very small. Besides, since we use the
data rendered by executing three phase method minus the data of direct
solar part and plus the direct sun coefficient for rendering data of five
phase method, the data of some measure points which are close to the
window rendering by five phase will be twice or three times lower than
that by three phase.
So what is the actual difference of data between three phase and five
phase? Are the data rendering by five phase definitely similar to that by
three phase?
Thanks,
Clarence
------------------------------
*发件人:* Sarith Subramaniam <[email protected]>
*发送时间:* 2017年11月27日 5:50
*收件人:* Radiance general discussion
*主题:* Re: [Radiance-general] Generate sky-matrix by using TMY weather data
Hi Clarence,
If by null you are implying zeros, then the generated files are fine. Your
first gendaymtx command ( -m 1 -d) will generate a sky matrix that is
almost entirely zeros except for radiation values in 3-4 patches per hour
during day-time. The second gendaymtx command (-m 2 -5 0.533 -d) will
generate a file that contains radiation values only in a single patch per
hour. If the direct-normal radiation data for a particular hour is zero,
then the radiation values in all the patches for that hour in direct-sky
matrix and sun-matrix will be zero as well.
Sarith
On 11/26/2017 08:26 PM, Wang Clarence wrote:
Dear all,
When I created direct-only sky-matrix and sun-matrix of Hong Kong region
by using commands "epw2wea" and "gendaymtx", the results seemed weird. The
data of .smx file I rendered almost were null, so was the data of New York
City . I had no ideas about its correctness. Anyone could help me out of
confusion?
#Generate a direct-only sky-matrix for the sun coefficient calculation. #epw2wea weather/CHN_Hong.Kong.SAR.450070_CityUHK.epw weather/HK.wea #gendaymtx -m 1 -d weather/HK.wea > skyVectors/HKd.smx
#Generate a sun-matrix for the sun coefficient calculation. #epw2wea weather/CHN_Hong.Kong.SAR.450070_CityUHK.epw weather/HK.wea #gendaymtx -m 2 -5 0.533 -d weather/HK.wea > skyVectors/HKsun.smx