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Space Type | Target daylight illuminance | Minimum % of space to comply for target lx | Minimum daylight illuminance | Minimum % of space to comply for min lx |
Spaces lit with windows | 300 lx for more than half of the daylight hours in the year | 50% | 100 lx for more than half of the daylight hours in the year | 95% |
Spaces lit with rooflights | 300 lx for more than half of the daylight hours in the year | 95% | – | – |
Notes
Select location for climate based calculation on Project Settings dialogue.
All weather data files must be in epw format and located in below folder:
Autocad: %appdata%\MBS Software\Waldram Tools\Climate Files
Revit: %appdata%\MBS Software\Revit Waldram Tools\Climate Files
For new locations, the .epw file can be downloaded from the energy plus website.
Select the region then the country then the location and then select epw to download the file.
Once downloaded copy the .epw file to the abobe appdata folder.
This setting is project specific and needs to be set per job.
Assessment Criteria are set per project in Project Settings dialogue > Climate Assessment Criteria tab.
Setting SDA BREEAM Criteria
All the entries on BREEAM Regulations Table 5.3 are predefined based on the BREEAM New Construction 2018 and loaded as default in Criteria table dialogue.
Each property and room type pair in BREEAM Regulations Table 5.3 is translated into one or two rows(based on number of credits, target lux, occuppied hours) in the dialogue.
If a property, room type pair has different credits, target lux or occupied hours one row is added for each credit in the table dialogue.
The Selected column displays the criteria that are set for calculation. The SDA calculation uses the
registered property and space type of a room to query its assessment criteria from the above table. If more than
one records exists for this property and room type, the Selected is returned from the table. If no records exists
the default “Other Building Types” criterion is used.
As an example, below Staff room type in Healthcare property has two entries for 1 Credit and 2 Credit with different occupied hours.
Two records are added to the table with the corresponding values for credit value, target lux and occupied hours.
The first entry for credit 1 is selected for calculation.
– To Add new criterion fill in the text boxes with corresponding criterion and press the New Row button. Note that
the AreaToComply column takes value between 0 – 1.
– To Delete an existing criterion select the row on the table and press the Delete Selected Row button.
– To Update an existing criterion simply change the values on the table.
Setting SDA EN17037 Criteria
The criteria is set according to EN17037 Regulations. The criteria are fixed and grouped by their rating. The Selected criterion is queried and used for calculation.
Notes for All Climate Criteria
Note 1: The output report displays criteria that has been set prior to running the calculation. In other words the selected criteria record is saved against the room on calculation time and same criteria is queried at report time.
Note 2: Changing the Selected criteria, changes to Target Lux, Target Lux Min, Target Hours requires rerunning the calculation. “Area To Comply” and “Credit For Area To Comply” does not require rerun.
Average Daylight Factor
The average daylight factor is the average indoor illuminance (from daylight) on the working plane within a room, expressed as a percentage of the simultaneous outdoor illuminance on a horizontal plane under an unobstructed CIE Standard Overcast Sky.
Point daylight factor
A point daylight factor is the ratio between the illuminance (from daylight) at a specific point on the working plane within a room, expressed as a percentage of the illuminance received on an outdoor unobstructed horizontal plane. The minimum point daylight factor is the lowest value of the daylight factor on the working plane at a point that is not within 0.5m of a wall.
Uniformity
The uniformity is the ratio between the minimum illuminance (from daylight) on the working plane within a room (or minimum daylight factor) and the average illuminance (from daylight) on the same working plane (or average daylight factor).
To generate stencil image from room polyline at working height:
1. Open MBS render dialogue by typing MBSRndr
2. Set the Raytracing method to Radiance in Settings > Ray tracing tab
3. Select Stencil DF in Render dialogue.
4. Set Image Quality to either Low, Medium, High. This type of rendering can take very long time on medium or high mode.
5. Click on Render button. It then asks to pick of the room polyline from the model. Press Enter or Right click after selecting the room and rendering starts.
Specular material that reflects Sun beam directed towards the view point is detected
as glare source and is marked in colour banding on the image.
The process to create the image is as follows:
1. Set the location in Project Settings > General tab by selecting the weather file.
2. Assign specular material (ThinGlass, Mirror, Metal and Plastic) in Material dialogue to all surfaces
that are considered to be potential for reflecting glare. All registered windows are
automatically applied ThinGlass material and no material definition is needed in the material dialog.
3. Open the Render dialogue. Select the view point and direction either by entering the
coordinates or picking them from the model by pressing the button next to the input boxes.
4. Select Potential Glare option
5. Change Camera type to Fisheye and set the view angle accordingly.
The view angle for fisheye is between 0 to 180.
6. Optionally change the driver’s age. Default age is set to 65 to give the worst case result.
7. Display Hours option can be ticked to show the time on the image. If the Display hour every is set to Zero, then only the hour texts are shown e.g. 08:00 or 09:00.
If the Display hour every set to non zero value e.g. 15, then the hour and minute for the interval will be shown e.g. 08:15 or 08:30. This option can cause the image creation to take longer for smaller minute intervals.
8. Tick “Create Report” option to generate csv report for the rendered image.
The report contains information for every pixel that has glare occurrence.
This includes date and time, glare intensity in cd/m2, distance from the glare, field of view angle of the glare.
The report is created in [Drawing Filename]_Waldram\Images\GlareTest folder.
9. Start the Subpixel sample with at least 50 and Increase it by 25 to render a sharp image. The noise in the image
is inversely proportional to the square root of this number.
10. Press Render button.
For the assessment of daylight glare EN17037 please refer to the annual occurrence.
This is a point-in-time calculation. Radiance evalglare program is used to calculate DGP value.
According to En17037 glare is defined as:
“Condition of vision in which there is discomfort or a reduction in the ability to see details
or objects caused by an unsuitbale distribution or range of illuminance, or by extreme
contrasts.”
DGP is defined as:
“the probability that a person is disturbed instead of the glare magnitude as a glare
measure. This new probability function is called daylight glare probability, DGP“.
It is an approach to consider both illuminance at eye level and individual glare sources of high luminance to estimate the fraction of dissatisfied persons.
According to En17037:
“DGP can be applied to any daylight oriented indoor space which is mainly side-lit and where
the expected tasks are comparable to office tasks.”
DGP values can be categorised in following ranges
Criterion | Daylight Glare Probability(DGP) |
Glare is mostly not-perceived | DGP <= 0.35 |
Glare is perceived but mostly not disturbing | 0.35 < DGP <= 0.40 |
Glare is perceived and often disturbing | 0.4 < DGP <= 0.45 |
Glare is perceived and mostly intolerable | DGP >= 0.45 |
To render an image for DGP calculation follow below process:
1. Set the Raytracing method to Radiance in Settings > Ray tracing tab
2. Set the Sky to clear CIE sky type Settings > Ray tracing tab.
Note: changes to sky type requires model reconverison for Radiance option.
3. As this is a point-in-time calculation, location, date and time have to be set in advance
via Project Settings dialogue > General tab.
Based on the provided threshold either of the two methods are used for detection of glare sources:
a. Calculate the average luminance of the entire picture and count every section as a glare
source that is x-times higher than the average luminance.
For this method try values less than 100: this factor multiplied by the average luminance in the entire picture will be used as threshold for detecting glare sources.
b. Take a fixed value and count every section as a glare source that is higher than the fixed value.
For this method try values over 100: the value is used as constant threshold in cd/m2;
Default option sets the threshold factor to 5.
4. Select a view point either by providing the coordinates on the input box or picking a point
within the room(work plane).
EN17037:
Testing position should be either a current used position of a person(workplace or often used position) or a position, which might be used and which might have a glare problem.
Such positions are usually close to the facade and/or facing facade orientations.
The viewing direction of the measurement devices should face towards the facade parallel
to the floor and towards the azimuth direction of the sun. The height of the view point
should be in 1.2m height.
5. The camera type automatically is set to Fisheye. And the field of view angle is set to 180 degree.
6. Set the desired image quality and press Render. The yellow areas on the image displays
the glare sources.
7. DGP value along with other glare metrics are calculated and saved in a text file in
[ModelName]_Waldram\Images\GlareTest
dgp,dgi,ugr,vcp,cgi,Lveil: 0.416646 25.267189 30.691992 0.000000 36.333500 706.391235
1. Open the Render dialogue
2. Specify location by selecting the corresponding climate file in Project Settings General tab.
3. Pick Radiance or Pathtracing from the Raytracing Method box.
4. Set sky type, date and time on the Settings tab.
4. Select Existing or Proposed model from the Model box.
5. Camera position and look At can be set in two ways:
a. Either tick the Override settings from current view to setup the camera to AutoCAD current view. This option works better in AutoCAD Perspective mode.
b. Or press the View Position box button to select the position from the model. Repeat the process for Look At.
6. Horizontal field of view is set via View Angle box. The effect is similar to zoom in or out
7. The image box can be resized manually through resizing the dialogue or by setting the desired resolution in Resolution box and pressing the resize button.
If the resolution is bigger than the display screen the image is rendered in the given dimensions but displayed to the image box size.
Optional Settings under the Settings tab:
– Picture box image can display the progress by ticking the “Show Progress” option.
– Tick Interactive rendering to pan / orbit the rendered image within the picture box. Hold left mouse button down to pan the image. Hold right mouse button down to rotate the image.
There are three Shading mode supported in Path tracing mode:
a. Global Illumination which produces unbiased path-traced simulation of light paths. This is the default mode.
b. Ambient Occlusion option accounts only for the visiblity term. A cosine-weighted visibility factor calculated for the hemisphere of a surface point. An example is demonstrated here.
c. Local Shading mode quicken the rendering but removing diffuse inter-reflection from calculation. Phong-shading model is used to render materials with pre-defined three directional lights.
8. Set pixel samples number and press Render. The noise is inversely proportional to square root of this number: four times more samples are required to decrease the error by half.
The process is same as described for rendering normal images. The maximum range of legend colours
is set in Settings tab > Irradiance and Falsecolor tab.
The minimum is always set to zero. The maximum value can be set and is interpreted as follow:
Values between 0 to 100 is used as Daylight Factor or Sky Component ratio. Values above 100 are taken as absolute lux value.
If Radiance is selected as the rendering method, two false color image modes are provided:
– Gradient option produces smooth interpolation between values on the image.
– If contour lines are desired rather than just false color image, the Contour Lines option can be used. These lines are placed over the normal Radiance picture rather than falsecolor image.
– Contour Bands produces contour bands instead of lines, where the thickness of the bands is related to the rate of change in the image.
Radiance false color image uses pre-defined Radiance pm3d color palette with 8 colours.
The below image shows daylight factor contour lines with corresponding values set in legend, for an indoor scene.
An hdr file format is saved along the png format, loaded through Tools > Load hdr image, which can be used to display
the image with different legend colours without re-rendering the image.
Objects in Proposed and Existing group would cast shadows same colour as their material colour.
New: A background texture image can be set by inserting a Raster image into the model. Make sure the image belongs to either of the analysis groups.
Tick New Shadow Only option to exclude part of the coloured shadow that already is rendered under the existing scenario.
View to the outside provides visual contact with the surrounding, so as to supply information for orientation, to experience the weather changes and to follow with the time over the day.
The view quality depends on
According to EN17037:
- “The criteria for view out concerns the utilized area” section 5.2.2
- “View to the outside should be assessed from selected reference points corresponding to where people are located within the utilize area”. section 5.2.1.
- “Three levels of view out, horizontal sight angle, the distance to outside view, and the number of layers are assessed from reference positions.” section A.3
And regarding the required % of the utilized area for Horizontal Sight Angle and Distance Out C.3 states that
The reference points can be at any potential location within the utilized area of the space.
Implying that 100% of the utilized area is required for the criterion to pass. This parameter can be set to a different value within the software. Refer to the below section on where to set this.
The Criteria for Minimum View Out:
Indicative points of the projection should be at points in the room where people are actually sitting (eyelevel 1.2 m over the floor) or standing (eyelevel 1.7 m over the floor).
Assessment of the view outwards from a given position
The Settings for View calculation can be set from Project Settings Results tab:
Outside Distance is calculated across the utilized area for each reference point. The rating is done as follow for each reference point:
The averaged distances to the outside obstructions are calculated for each of the three bands(minimum, medium, high) separately.
It is the average of all distances to the outside obstructions that fall within a specific radius(correspond to the band).
This is considered as valid only if the obstructions within the band obscure the view more than a specified threshold(e.g. 10% threshold in above figure).
Otherwise the band is regarded as having no obstructed view and no shortest distance is recorded.
A full sphere fisheye view is rendered for each reference point to accumulate distances on each band from all the openings.
The View Test dialogue can be used to visualize the three tests.
Using of the Material Table requires enabling the option by ticking the Use Material Table box on the Materials Dialogue.
– Using Material Table Mode
This enables you to assign materials reflectances or transmittance to selection of layers.
Once a material is assigned to a layer, through adding a record to the table,
can be modified freely WITHOUT a need to re-convert the model. Therefore this gives more flexibility on experimenting different materials and parameters for an analysis.
Model conversion automatically creates a record on material table for any layer that has not been assigned a material in advance.
Default diffuse material with reflectance read from layer color(r = 51, g = 51, b = 51 translates to 0.2, 0.2, 0.2) is used for any such layers.
As in below image they will be highlighted in red color to emphasis the difference and the need for revision.
Adding a new record or Removing one requires model re-conversion.
This is also the case on making any change to the model, like adding deleting objects or changes to the object layer.
– Not Using Material Table Mode
Default diffuse material with reflectance read from object color(r = 51, g = 51, b = 51 translates to 0.2, 0.2, 0.2) is used.
Using the material table you can assign materials reflectances or transmittance to selection of layers.
Once a material is assigned to a layer, through adding a record to the table,
can be modified freely WITHOUT a need to re-convert the model. Therefore this gives more flexibility on experimenting different materials and parameters for an analysis.
Use Filter Layer name box to filter the list.
Tick Hide MBS Layers to remove all MBS specific layer names from the list.
The layer list displays only the layers that do NOT have any material assigned to. This works as a safety checking to know which layers have been left with no materials.
It is possible to create new material definitions other than the predefined ones.
TransTree is a mix of Diffuse Reflection(representing leaves) and Specular Transmission(the gaps). This material is suitable for simulating trees on BRE (ADF, VSC, APSH) or Daylight Factor calculations. The Reflectance value on VSC, ADF calculations only reflects in terms of the colour as no reflected light is accounted for. The Transmittance value is the overall transparency of tree crown as the ray enters and exists the tree volume. Follow the below steps to assign tree material to a layer:
Put objects in the model to their corresponding layers. Normally for indoor calculations like Climate or Daylight Factor the scene is divided into two groups of objects, external obstructions and room internal surfaces.
and What happens to registered Windows Glazing Transmittance?
The detection of room indoor surfaces on Revit edition of the software is done automatically and can be visualized by Highlight Room interior command.
For AutoCAD edition separating floors, walls and ceilings objects and put them in their layers(e.g. all walls objects to “wall” layer) can be a challenge.
Any solid object has to first get exploded to access the individual surfaces. Care must be taken to put back the exploded objects back into their original ClassicGroup.
The ExtractRoomSurfaces command is a utility command in AutoCAD that automatically extracts floors, walls and ceilings and put them in corresponding layers.
Two Monte Carlo backward ray tracer are provided: Path tracing and Radiance software.
Gradient legend has five different colour options. All options except MBS and Rainbow allow users to change the colour. The minimum and maximum values are pre-defined for all the calculation types which support legend creation. The values can be changed by user if required. All options except Rainbow create 21 colours in total. Rainbow creates 25 colours in total. Intermediate colours are added to avoid colour contrast between values in two intervals. The breakdown of intermediate colours is as below:
Legend interval
The interval for legend values is created by dividing the min and max values equally to the legend colours.
Interval values for legend colours are calculated using the formula (Max value – Min value) / (total colours in legend – 1). The last colour is for all values greater than max therefore (total colours – 1) is used.
For example, The interval of values per MBS legend colour for VSC legend with min of 0 and max of 27 will be calculated as below.
(27-0) / (21-1) = 1.35
There are no default values for non-gradient legend mode. Users must define the range for each calculation type before running the calculation. If non-gradient legend values are not defined for the calculation, the default gradient mode is used.
Select the calculation type on the combo box to define a non-gradient values. Then choose a colour and enter a value. The values must be in ascending order. The first value will be the minimum value and last value will be maximum value for any calculation. The ratio colour and values fields can be left empty if the calculation is only being run for Proposed scheme.
If BRE option on Non-Gradient mode is ticked, VSC and APSH legends will be customised according to the BRE criteria. The legend will be created with just three colours for Pass, Nearly Pass and Fail. The colours can be changed by the users. The pass values for VSC and APSH is taken from Project settings Assessment criteria section.
For Example, for VSC calculation if the result >= 27 (or) loss < 20 % then it passes, if the result >= 26 (or) loss < 21 % (Tolerance = 1) the it is Nearly Passed, otherwise it will fail. The legend will show Pass, Nearly Pass and Fail results. If the calculation is run for neighbour scheme only one legend is created.
This is to be checked in the reference point at the centre of the window width and at the
inner surface of the aperture (façade and/or roof). For multiple apertures in different façades it is
possible to cumulate the time of sunlight availability if not occurring at the same time. The reference
point is minimum 1,2 m above the floor and 0,3 m above the window sill if present.
NOTE 1 If the sill height of the window is higher than 1,2 m above the floor, the reference point is located 0,3 m
above the window sill. If window is without sill the reference point is located 1,2 m above the floor, Figure D.3.
NOTE 2 To allow flexibility for rooms orientation the angle of window normal αwn,s = 120° measured from
South and the minimum sun height γs,min are applied. Solar altitudes below those stated in Table D.1 are neglected in the evaluation.
Minimum recommendation for exposure to sunlight
The minimum recommendation is that the room should receive possible sunlight for a duration
higher than 1,5 h (supposed to be cloudless) on March 21.
Table A.5 proposes three levels for exposure to sunlight.
Sunlight Exposure | |
Recommendation for minimum exposure to sunlight | 1.5 h |
Recommendation for medium exposure to sunlight | 3.0 h |
Recommendation for high exposure to sunlight | > 4.0 h |
To close the shape press the start polyline
To close the shape at specified high, press and pick a point on the image. The shape will be closed by adding three perpendicular segments as in the image below.
[optional] You may press “Cut diagram” button to cut the drawn shape on the image and update Sky Component value. This does not create/cut the 3d model. Instead it can be used to check whether the resulting Sky Component is close to the desired value.
[optional] To draw new shape it is suffice to press Erase button.
Renumbering can be useful if windows and rooms are added or removed from the model after the initial registration.
It can also be useful if the numbering of the windows needs to start from a different position.
Renumbering can be done for Partial Floor, Single Floor or All Floors in a building. Single and All Floor renumbering need the building polyline and building name block (Both of them must be on the building_polylines layer).