Daylight for Autocad Knowledge Base

What layer names are used by Register by model to detect the polylines?
The Register Model section – Layers tab shows list of all the layer names. Create Registration Layers button creates all the required layers in one go.

Can only windows be registered on their own?
Yes. Without Rooms option should be ticked.

Can Rooms be registered on their own?
Yes. If windows are already registered with same building and floor address.
Perform 1. Pre-Reg Room then 3. Register by model. Windows will be linked to the rooms
No. If windows are not registered with same building and floor address.

How can window/room address be updated if they are added/removed after the initial registration?
In Modify Dialog (MBSMODIFY command), Re-Number button allows to renumber windows and rooms. Building polyline and building name block are required. Re-Numbering can be done for partial floor, single floor or entire building.

Can window/room name be started from a different location in the building?
The first window and the order is determined by the starting point and order of building polyline vertices. Redraw the polyline to match the requirement and perform renumbering.

Why could not the building name and/or starting floor be determined from the building detail block?

• The block must be on Building_Polylines layer.
• The block’s base point must be within the outlining building polyline
• The starting floor name must already exist on the floor name combobox(loaded from FloorList.txt)

Material Dialogue can be opened by clicking on the material dialog icon on the tool bar or by clicking the Tools Menu then Materials. Using of the Material Table requires enabling the option by ticking the Use Material Table box on the Materials Dialogue.

–  Using Material Table Mode

The material table is empty for a new project. The list is populated with the materials based on the layer colour RGB value when the model is converted for the first time. It an then be modified WITHOUT a need to re-convert the model. Therefore this gives more flexibility on experimenting different materials and parameters for an analysis.

Default diffuse material with reflectance read from layer colour (r = 51, g = 51, b = 51 translates to 0.279, 0.279, 0.279) is used for objects on that layer. RGB gamma correction is applied in order to make the rendered image look similar to when viewed in a Monitor.

Clearing the material list and Importing the material list from another project requires model reconversion.  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 layer colour (r = 51, g = 51, b = 51 translates to 0.279, 0.279, 0.279) is used for objects on that layer. 

Updating the Material for Layer(s)

1. Select one or more rows from the layer – material list on the  left hand side for which you want to update the material.
2. Select the desired material from the Material list on the right hand side and press Edit Material for Selected items.
3. Press Update Layer Material.
4. Repeat steps 1 – 3 as necessary for the layers.
5. Press Apply and Close the dialog.
6. Updating the materials this way doesn’t require model reconversion

Adding New Material to the library

1. Click on the Open Library button
2. Select a existing Group or Type a new group name for the material on the Group combo box.
3. Type a unique name on the material name text box.
4. Select a Material Type from the Type combo box. See below for detail on types.
5. Assign material properties on the relevant text boxes.
6. Press Add and Close this dialogue.
7. Remember to Press Apply on the Material dialogue.

• Diffuse surface reflects light uniformly over the entire reflecting hemisphere. A Lambertian (or diffuse) surface appears equally bright from all viewing directions.
  The reflectance parameter represents the fraction of the incident energy that is reflected at a surface. The parameter has three components which range from 0 to 1.
• Mirror (specular reflection) surface only reflects light in one specific direction.
• ThinGlass is a special case of dielectric, infinitely thin and therefore does not change the transmitted ray direction. It is modelled as a single surface. The default refractive index is 1.52.
  Transmittance is the ratio of the total transmitted light to the incident light which includes multiple inter-reflections in a layer of glass.
  The parameter is a single value from 0 to 1 – Reflectance field is disabled as it is a function of angle, refractive index of the material and transmissivity.
  Transmissivity applies to a single pass of light through a layer of glass and excludes multiple interreflections within the medium.
  ThinGlass is translated to Radiance glass material. Transmittance value is converted to transmissivity for the Radiance rad file.
• TransTree is a mix of Diffuse Reflection (representing leaves) and  Specular Transmission(the gaps). See How to assign the Materials for Trees? for more details.
• Translucent material is a mix of diffuse reflectance/transmittance and perfect/glossy specular reflectance and transmittance. It describes diffuse and glossy specular reflection and transmission through the surface.
  Translucent parameters are well described in this link: http://www.schorsch.com/en/software/rayfront/manual/transdef.html
• BSDFRadiance material, only valid on Radiance method, is to define material for complex glazing system.
  The input is an xml file containing BSDF matrix data. This file can be generated using WINDOW 6.0 BERKELEY LAB application.
  Please follow instruction on BSDF Files for Radiance Renderings page.

Assign Tree Material from pre-defined BRE trees

TransTree is a mix of Diffuse Reflection (representing leaves) and Specular Transmission (the gaps). This material is suitable for simulating trees on BRE (VSC and ADF) or Daylight Factor calculations. The Reflectance value on VSC and 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 the tree objects with the same transparency to a layer.
• Then Open the Materials dialogue and assign one of the predefined BRE tree materials.
• The trees mentioned BRE Site Layout for Daylight & Sunlight Appendix H Table H1 are included in the material library.

*For Sunlight calculations, they should be run with opaque trees and without trees if necessary
(BRE Site Layout for Daylight & Sunlight Appendix G3)

*For SDA calculations please refer to https://www.mbs-software-uk.com/knowledge/sda-calculation-with-trees/

Creating a custom Tree material

• Open Material dialogue then Press Open Library button
• Create a new TransTree type material
• The reflectance values are used during DF calculation only. It is used for the colour of the tree in case of VSC and ADF calculations.
• The transmittance is converted automatically to consider the overall transparency of the tree crown as the ray enters and exits the tree volume.
• For example 50% overall transparency should be input as 0.5 which will then be converted to 0.707 (√0.5) to adjust for the ray entering and leaving the tree crown. This can also be seen on material preview area.

• Balconies are supported for all calculations including Ray-traced based (Daylight Factor and Climate) and BRE (VSC, APSH and ADF).
• Put the balcony objects with the same transparency to a layer.
  • Region or objects with single face should be used.
  • Using objects with multiple faces may result in the transparency being applied multiple times.
    • If the overall transparency of the balcony modelled as solid is 0.60,
    • Then the ThinGlass transparency should be √0.60 i.e. 0.775
• Open Material dialogue then Press Open Library button
• Create a new ThinGlass type material
  • The normal transmittance value should be in put as unit value e.g. 0.6 for 60%
  • Refractive index of 1.52 is define as default.
  • Press Add and Close this dialog.
  • Remember to Press Apply on the Material dialogue.
• Then Assign the material to the layer with balcony objects on the Materials tab.
  Refer to Updating Material For Layer topic for details.

Gradient legend has five different colour options. All options except MBS and Rainbow allow the 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 the user if required.  Intermediate colours are added to avoid colour contrast between values between two intervals. The breakdown of intermediate colours is as below:

• Two colour: 2 for the given colours and give value from interpolated colours field interpolated colours between them.
• Three colour:  3 for the given colours and give value from interpolated colours field is applied between first and second and second and third colour.
• Custom colour: 11 for the given colours and 10 for the mid colour between them except the last one.
• Rainbow colour:  7 for the given colours and 18 for the intermediate colours between them. (give value from interpolated colours field between each consecutive colour except the last one)
• MBS colour: 11 for the given colours and 10 for the mid colour between them except the last one.

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

Gradient Legend is supported by the following calculations

Facade

• VSC, APSH, SE, Amenity, DF and Solar Radiation

Solids

• VSC, APSH, SE, DF 

Result Images

• All room calculation types.
• ROL, DD and Amenity use these colours when Use Image Texture for Room/Amenity Results option in Application Settings is ticked.

• Select the calculation type on the combo box to define a band legend 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. 

Band Legend is supported by the following calculations

Facade

• VSC, APSH, SE, Amenity, DF and Solar Radiation

Solids

• VSC, APSH, SE, DF 
• Pass Fail legend will be used for calculation which don’t support band mode.

Result Images

• All room calculation types.
• ROL, DD and Amenity use these colours when Use Image Texture for Room/Amenity Results option in Application Settings is ticked.

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.

Pass Fail Legend is supported by the following calculations only

Facade

• VSC, APSH, SE and Amenity
• Band legend will be used for DF and Solar Radiation if Pass Fail legend is set 

Solids

• ROL, DD, VSC, APSH, Amenity, SE and DF

Result Images

• None
• Band legend will be used if Pass Fail legend is set 

Any registered windows will automatically get ThinGlass material(or glass in Radiance format). Therefore it is not required to create records for them in Material Table. The material requires normal incidence transmittance for its definition which is derived from the ADF properties of the window at the registration time.

Td: Diffuse Transmittance (is used in BRE ADF formula)

Tn: Normal Incidence Transmittance

According to BRE Appendix C:

“diffuse transmittance can be found by multiplying the manufacturer’s normal incidence light transmittance by 0.91”

Tn = (Td ÷ 0.91) 

And from BS8206 15.2:

“If daylight factors are calculated from the overall aperture area in the wall or roof, instead of the net glazed area, a further correction factor should be used. If there are any other obstructions, such as curtains or structural supports, the overall transmittance should be reduced in proportion to the area of opening that they obscure.”

T = Tn × GM × MF

T is the value used to derive parameters required for definition of glass material on any ray-tracing based Climate and Daylight Factor calculation.

GM: Frame Factor
MF: Maintenance Factor

Terms and Definitions

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).

1. Minimum value of average daylight factors required

2. Daylighting uniformity criteria

Daylight Factor Criteria

UK National Annex

The UK Annex is intended for “hard to light” dwellings.

The targets for DF is linked to the lux targets defined for BS EN17037 SDA (This can be accessed via Project Settings Climate Daylighting tab). The target DF is calculated based on the target illuminance and the median external diffuse illuminance. e.g. For London Gatwick, median illuminance is 14100. The equivalent target DF for 100 lux is (100 / 14100) % 100 % i.e. 0.7%

The target DF is to be met for 50% of the time over 50% of the space

Daylight Factor Criteria

The targets for DF is linked to the lux targets defined for EN17037 SDA. (This can be accessed via Project Settings Climate Daylighting tab). The target DF is calculated based on the target illuminance and the median external diffuse illuminance. e.g. For London Gatwick, median illuminance is 14100. The equivalent target DF for 300 lux is (300 / 14100) % 100 % i.e. 2.1%

The target DF is to be met for 50% of the time over 50% of the space. The min target DF is to be met for 50% of the time over 95% of the space.

Illuminance Criteria

UK National Annex

The UK Annex is intended for “hard to light” dwellings.

The illuminance targets for BS EN17037 SDA can be accessed via Project Settings Climate Daylighting tab.

The target Lux is to be met for 50% of the time over 50% of the space.

Notes (Also Applies to EN17037 Criteria too)

• Daylight Hours: The hours of daylight are determined by rank-ordering (i.e. from highest to lowest) the 8760 values for diffuse horizontal illuminance and then extracting the first (i.e. the highest) 4380 hourly values. Note that the retained (i.e. highest) 4380 values may include some zero values, or that the discarded 4380 values may include some non-zero values.
  This is to be expected given the nature of illuminance data in climate files and does not affect the outcome.
• The relevant area of the space plane covers the entire space, and is located 0.85m above the floor.
• A perimeter area is excluded from the area of the space, because locally, illuminances are not relevant to the assessment of daylight provision, since the illuminances can be excessively high (near windows) or excessively low, next to opaque walls. A perimeter area is the area located next to the walls of the space, and should be excluded in daylight calculations.

Illuminance Criteria

The illuminance targets for BS EN17037 SDA can be accessed via Project Settings Climate Daylighting tab.

For spaces with daylight openings in vertical and inclined surface, The target Lux is to be met for 50% of the time over 50% of the space. The min target Lux is to be met for 50% of the time over 95% of the space.

For spaces with daylight openings in horizontal surface, The target Lux is to be met for 50% of the time over 95% of the space. There is no minimum target lux.

Terms and Definitions 

Average daylight Illuminance

Daylight illuminance for all points in the space for a specific hour (e.g. 1st Jan 8 AM) is averaged. If this average is over the target lux (e.g. 300 lux) value, the hour will count towards the achieved hour for the target lux.

Minimum Daylight Illuminance

The lowest point daylight illuminance in the space at a specific hour e.g. 1st Jan 8 AM) on the working plane within a room. 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. If this lowest lux value is over the target lux min value (e.g. 90 lux), the hour will count towards the achieved hour for the target lux min.

Setting up Weather data and Location

Select location for climate based calculation on Project Settings dialogue > General tab > Location section. All weather data files must be in epw format and located in below folder:

Autocad: %appdata%/MBS Software/DaylightForAutocad/Climate Files
Revit: %appdata%/MBS Software/DaylightForRevit/Climate Files

For new locations, the .epw file (IWEC format) 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 above appdata folder which can be opened by clicking the Folder icon next to the climate file location combo box.

This setting is project specific and needs to be set per job.

Setting up Climate Hours

• Before running the calculation, the regulation and annual daylight hours options have to be set through Project Settings > Climate Daylighting tab.
• The test has to be run separately for each regulation. Results are saved per regulation and thus once they are calculated, corresponding reports could be outputted without a re-run.
• The recommended daylight hours for BREEAM, BS EN17037and EN17037 is Sunrise to Sunset.
• For BS EN17037 and EN17037, 50% of the hours with the highest illuminance (4380 hours) is used instead of all the hours between sunrise and sunset.
• The filter hour is inclusive for the start hour and exclusive for the end hour.
  For example, if the occupancy starts at 9 AM and finishes at 5PM, the filter hour should be set to 9 to 17 (8 Hour Occupancy)

The DI results can be presented visually in 4 different ways.

• As shown in the image, the Meets criteria option will show a single colour image for the room based on whether Achieved hour > Target Lux and/or Worst lit point achieved hour > Target Lux Min are met or not.
• Please note that the rest of the three options are alternative presentation of the result and do not show the achieved hour for target lux and target lux min as averaged over the space
• The Lux (Avg Over Year) option can be used to show the average lux achieved by each point in the room over the year.
• Hours (Over Year > Req Lux) option can be used to show the number of hours when each point in the room achieve the req lux.
• Hours (Over Year > Req Lux Min) option can be used to show the number of hours when each point in the room achieve the req lux min.

The DI Excel result contains the results for the main criteria as well as some alternative results.

As shown in the DI criteria results image,

• The Req Lux Achieved Hours column shows the total number of hours  when lux value averaged over the space is at least 300 Lux.
• The WLP Achieved Hours column shows the total number of hours  when the worst lit point lux value (except foe the points within 0.5m of the wall) is at least 90 Lux.
• The Meets Criteria column shows Yes, If both Req Lux Achieved Hours and WLP Achieved Hours are more than the 2000 hours (Req hour per year). 

The Alternative result columns are to the right of the Meets criteria column and are added to give alternative results for each points over the year. 

• The Avg Annual Lux column shows the average lux value based on the average lux achieved by all the points in the room. Each points average lux value can be shown by using the Lux (Over the year) option in Legend settings. 
• The % of Area Meeting Req Lux column shows the percent of the points which have an average of at least 300 Lux.
• The Avg Annual Achieved Hours column shows the average achieved hours value based on the achieved hours with at least 300 lux achieved by all the points in the room. Each points achieved hours with at least 300 lux can be shown by using the Hours (Over Year > Req Lux) option in Legend settings.
• The % of Area Meeting Req Hours column shows the percent of the points which achieve 2000 hours with at least 300 Lux.
• The Avg Annual WLP Achieved Hours column shows the average achieved hours value based on the achieved hours with at least 90 lux achieved by all points in the room. Each points achieved hours with at least 90 lux can be shown by using the Hours (Over Year > Req Lux Min) option in Legend settings.
• The % of Area Meeting Req Hours (WLP) column shows the percent of the points which achieve 2000 hours with at least 90 Lux.

The Spatial Daylight Autonomy (sDA) calculation is based on the EN 17037 methodology for daylight assessment, in accordance with BREEAM guidance. For further details, please refer to GUIDANCE NOTE 50, Section 1.3.

BREEAM Recommendation

The EN 17037 gives three levels of recommendation for daylight provision in interior spaces: minimum, medium and high.

• To meet the standard credits, a space only need to reach the minimum level.
• To qualify for the Exemplary credits, the space must reach the high level.

In both cases, the required minimum area that meets daylight levels depends on the building type and must meet in accordance with the standard and exemplary level credits.

For rooms that receive daylight from windows or sloping openings, enough light should reach the working area (the reference plane) for at least half of the year’s daylight hours. Specifically:

• A main brightness target (E_T) should be met in at least half of the space.
• A lower minimum brightness level (E_TM) should be met almost everywhere — at least 95% of the space.

Following table shows the exact light levels for window-lit rooms. A space is considered well-lit if it meets both the main brightness target (E_T) and the minimum brightness target (E_TM).

For rooms lit from above (such as skylights or roof openings), the main brightness target (E_T) should be met in almost the entire working area — at least 95% of the space — for at least half of the year’s daylight hours. Following table shows the required light levels for these top-lit spaces. Unlike window-lit rooms, there is no additional minimum brightness requirement (E_TM). 

Setting up Assessment Criteria

1. Open the Settings dialog.
2. Select the Climate Daylight tab.
3. In the Climate-Based Calculation section, set the regulation to EN 17037.
4. Click on … (options) and choose SDA Calculation.
5. Select the Targets values as needed:
   • For standard credit select the row with 300 lux.
   • For exemplary credit select the row with 750 lux.
6. If needed, update the target values and other criteria to match your project requirements.

SGA is an annual DGP calcualtion (Daylight Glare Probability).

BREEAM Recommendation

Limitation of Software

The software runs the SGA calculation for the entire room. To determine whether individual workstations meet the exemplary level criteria, the user must either perform a manual calculation using the grid point results or register each workstation as a separate room.

Setting up Assessment Criteria

1. Open the Settings dialog.
2. Select the Climate Daylight tab.
3. In the Climate-Based Calculation section, set the regulation to EN 17037.
4. Click on … (options) and choose SGA Calculation.
5. Select the Targets values as needed:
   • For example select Target DGP  0.4 to meet BREEAM medium Glare protection level.
6. If needed, update the target values and other criteria to match your project requirements.

BREEAM Recommendation

Annual Sunlight Exposure (ASE₁₀₀₀,₂₅₀ ≤ 10%)

No more than 10% of the occupied floor area in relevant building spaces may receive a daylight illuminance of ≥ 1000 lux for ≥ 250 hours per year.

Setting up Assessment Criteria

1. Open the Settings dialog.
2. Select the Climate Daylight tab.
3. In the Climate-Based Calculation section, set the regulation to LEED.
4. Click on … (options) and choose ASE Calculation.
5. If needed, update the Target Lux, Target Hours and Area to Comply to match your project requirements.

Default annual occupancy hours can be taken to be 8am to 6pm local clock time on Monday to Friday. This parameter can be modified by unticking the Sunrise to Sunset Option in Climate based calculation section.

ASE occupancy hours

BREEAM Recommendation

At least 75% of the floor area in 95% of relevant spaces must meet both of the following criteria:

• A horizontal sight angle of 28° or greater.
• A view that includes the landscape layer and at least one other layer (sky or ground) through a permanent opening.

Setting up Assessment Criteria

1. Open the Settings dialog.
2. Select the Assessment Criteria tab.
3. In the View section.
4. If needed, update the target values and other criteria to match your project requirements.
   • The target % of area required to meet criteria is taken from % of Utilized Area. This value must be 75% to meet BREEAM recommendation.
   • Target % of relevant space required to meet is taken from Target % of Spaces In a Building section. This value must be 95% to meet BREEAM recommendation.
   • A horizontal sight angle value is taken from Medium field of Horizontal Sight Angle section. 

View Out Assessment Criteria

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 (whichever is higher).

NOTE 1 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 (BS EN17037 guide) 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 hours (supposed to be cloudless) on March 21.

Table A.5 proposes three levels for exposure to sunlight.

Table A.5

The test date can be changed on Project Settings > Climate Daylighting tab.

The default date is set for March 21. 

Open Run dialogue and select Sunlight Exposure to run the calculation.

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.

Steps to create the Annual Potential Glare image and report

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 and images are saved in the [Model_Name]_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. The image on the right is rendered with 50 subpixel samples and is little bit blurry so it should be rendered with higher subpixel samples.

10. Press Render button.

Render FAQ

Understanding the image output

• Circles
  • The circles in the image represent 10 degree steps except the first and sometimes the last step. 
  • The image on the right side is created using a view angle of 60 degrees. The inner most red circle is a special one added to represent the 3 degrees of view angle (6 degree in total which is affected the most). The next three lines are for 10, 20 and 30 on each side and thus totalling the 60.
  • If the view angle is not a multiple of 20, then the last one will be the half of the view angle. e.g. if the view angle of 70 is used, then the circle lines will be for 3, 10, 20, 30 and 35.
• Colours
  • The colours in the glazed surfaces represent the colours for the month when the potential glare occurs.
  • A legend with the month name and the colours can be added to the rendered image by going to Render dialogue options > General tab and ticking Add header to the image option.

For the assessment of daylight glare EN17037 please refer to the annual potential glare.

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.“

Steps to render an image for DGP calculation

1. Set the climate file location Project Settings > General tab
2. Set the Raytracing method to Radiance in Application Settings > Ray tracing tab
3. Set the Sky to clear CIE sky type Settings > Ray tracing tab.
   Note: changes to sky type requires model re-conversion for Radiance option.
4.  As this is a point-in-time calculation, location, date and time have to be set in advance via Render dialog Options > General tab  (Click on the … button on the render dialog to open the options).
5. The default Glare DGP threshold is 7 and it can be changed in Render dialog options > Glare tab.

6. Based on the provided threshold either of the two methods are used for detection of glare sources:

   • Method 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.

   •  Method 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 

7. Select a view point either by providing the coordinates on the input box or picking a point within the room (working plane).
8. The camera type automatically is set to Fisheye.  Set the field of view angle as required.
9. Set the desired image quality and press Render. The yellow areas on the image displays the glare sources.

10. DGP value along with other glare metrics are calculated and saved in a text file in the [Model_Name]_Waldram/Images/GlareTest folder.

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.

Objects in Proposed and Existing group would cast shadows same colour as their material colour. Transient Shadow Test image can be rendered using CPU or the GPU.

1. Open the Application Settings > Calculation tab and choose the desired Rendering method. (GPU render require a compatible NVIDIA graphics card)
2. Specify location by selecting the corresponding climate file location in Project Settings > General tab
3. Open the Render dialog options > Transient Shadow tab and set the required test start and end time. 
4. Set the required interval (in minutes).
5. The individual equinox dates can be easily set by selecting the desired date from the combo box.
6. The Run All Dates option can be ticked to run for three dates 21 March, 21 June and 21 December in one Render. The times are in GMT.
7. In Image tab select Shadow Test and pick the model group from the box.
8. Set Camera mode to Perspective.
9. 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 the current view or a predefined camera. This option works better in AutoCAD Perspective mode. B. Press the View Position box button to select the position from the model. Repeat the process for Look At.
10. Horizontal field of view is set via View Angle box. The effect is similar to zoom in or out.
11. 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.
    The resolution can also be manually be set to a value bigger than the display screen.
12. 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.
13. The shadow images are saved in the [Model_Name]_Waldram/Images/ShadowTest folder. Image file name will include the day, month and the time. No image is created for the times where the sun is not present e.g. after the sunset. 

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 the New Shadow Only option to exclude part of the coloured shadow that already is rendered under the existing scenario.

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 Render dialog options > General tab > Raytracing Method combo box.
4. Also Set sky type, date and time on the same tab.

5. Select Existing or Proposed model from the Model box.

6. 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.

7. Horizontal field of view is set via View Angle box. The effect is similar to zoom in or out

8.  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. The resolution can also be manually be set to a value bigger than the display screen.
9. 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.

Optional Settings under the Options > General 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.

Shading Modes

There are three Shading mode supported in Path tracing mode:

1. Global Illumination which produces unbiased path-traced simulation of light paths. This is the default mode.
2. 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.
3. 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.

The process is same as described for rendering normal images. The maximum range of legend colours is set in Render dialog Options > 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.

Note:

Radiance falsecolor image uses pre-defined Radiance pm3d colour palette with 8 colours.
The image on the side shows daylight factor gradient image 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.

Adjust the exposure using the slider in Render dialogue. This linearly changes the image brightness. if the image is too bright or too dark, the level of the brightness can be adjusted
by changing the exposure level through the slider.

In Path tracing mode the slider updates the image immediately without a need to render the image.

In Radiance mode, the exposure takes effect after rendering it image again.

Alternatively you may tick “Open Radiance image with wxfalsecolor” option in Render dialog options > General tab to open the Radiance image in wxfalsecolor application to set the exposure directly. This  immediately updates the image without re-run.

• Open the Register Dialogue by clicking icon from menu bar or by typing MBSRegister command.
• Go to Facade Tab
• Enter the Grid Spacing and select Highlight Facade Colour (Selected
  objects are highlighted using this colour) as per your requirement.
• Type name for facade in Facade Name field. Alternatively, you can enable the auto name option from settings which will add the facade name automatically.
• Auto Naming option can be enabled/disabled from Register section in Application Settings. Similary, you can also set your own custom prefix to be used for facade name.
• Facade mapping can be done for
  • 3d solids, Regions and closed 2d Polylines.
  • 3d solid faces
  • Polyface, Polygon mesh and 3D faces.
• Select the appropriate Selection option.
• Select the objects. 
• Select button can be used multiple times to add objects in different parts of the model. Text message next to select and register bottom shows the total objects which are selected which should also be highlighted using the Highlight Facade colour. Button next to text messsage can be used to clear selected facade before registration.
• Click on Register.
• It is possible to create a classicgroup with objects supported for Facade registration (group name must start with FG_ ). The group then appears in the Selection list.

1. Open the Modify Dialogue by clicking icon from menu bar or by typing MBSModify command.
2. Go to Facade Tab.

From modify dialog, you can add / remove faces, rename facade, update grid spacing and unregister the selected facades.

Note: If the recently registered facade is not shown in the table, click on the Reload button above the table, which will repopulate the table.

Add Face

1. Click on the + icon in the table. This will show a new section called edit below the Grid Spacing section.
2. Choose the type of object you want to select from the model in the Selection Type option. 
3. Click 1. Select.
4. Select the relevant face you want to add. After selection, the selected count gets displayed as a text message below the buttons.
5. Next, click on 2. Add Faces. This will append the selected faces with existing faces.

Remove Face

1. Click on the – icon in the table. This will show a new section called edit below the Grid Spacing section.
2. Choose the type of object you want to select from the model in the Selection Type option. 
3. Click 1. Select.
4. Select the relevant face you want to remove. After selection, the selected count gets displayed as a text message below the buttons.
5. Next, click on 2. Remove Faces. This will detach the selected faces from the facade.

Rename Facade

1. Click on icon. This will show a new section called Rename.
2. Enter the desired name you want to give for the selected facade in Facade Name field.
3. Click on Rename button. This will update the name of selected facade in table.

Upgrade Grid Spacing

1. Select the Facades from the table. (You can select multiple facades at once.)
2. Enter the desired Grid Spacing in the Grid Spacing field.
3. Click the Update Grid button. The Total Point column gets updated once the grid point update is complete.

Unregister Facade

1. Select facades in the the table. (You can select multiple facades at once.)
2. Click on Unregister Facade button.

1. Go to the Calculation dialogue (MBSCalculation command) and convert the model groups by clicking the Convert button at the bottom right in the Convert tab.
2. Go to Run tab.
3. Under the Regulation and Calculation section, click on the Facade Tab. All the supported calculations for Facades are listed under this tab. 
4. Select the calculation type by clicking on the tick box and change the Facade  Name from the dropdown box displayed in the Entities Selection section if required.
5. All option from the Facade dropdown can be used to add all the registered facades in one go for selected calculation.
6. Before running, make sure the settings are right.
   1. Open Legends dialogue, you can select either Gradient or Bands.
   2. To get results on legend select “Display % of area for results” option. See Legend Settings Section for more details.
   3. After changing the Settings, click on OK.
   4. Open Application Settings > Calculations tab, enter Sky sub division angle for VSC calculation (5 degree is suggested).
7. Click the Run button at the bottom right in the calculations dialogue to run the calculation.

• Each calculation has its own layer (ex: FACADE_1_VSC_PROPOSED_FACADE).
• If you select “both” groups you also get the loss (ratio of proposed and existing) in its own layer (ex: FACADE_1_VSC_LOSS_FACADE).
• Use Realistic/Shaded visual style as mesh colours are not visible in Wireframe view.
• The facade legend can be found in [Model_Name]_Waldram\images\FacadeLegend folder. The image on the right is created for VSC Proposed using Gradient mode. 
• CSV report are automatically created in [Model_Name]_Waldram\Reports folder.

Clear Facade Result

1. Open Calculation dialogue.
2. Click on Tools in menu bar.
3. Click on Clear results > Facade Results.

Assessment of the view outwards from a given position

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 Settings for View calculation can be set from Project Settings > Assessment Criteria tab:

The ViewTest dialog (MBSViewTest command) can be used to visualize the three tests.

The image on the right shows outside distances from a point inside a room. The outside distance is calculated across the utilized area for each reference point. The rating is done as follow for each reference point:

• Distances to landscape layer is used. Distance to Sky and Ground are not used for outside distance to view.
• The average 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. 
• For example, In the image shown, the shortest distance to view is taken from the 0–<6 band as the % of view in that is more than the 10% threshold. If the % of view is less than 10% then the shortest distance will be checked in the 6- < 20 band and so on. 

The image on the right shows the falsecolor map for distance to view and other visible layers. Sky, Ground, Inside Room, Beyond lens and various distance band are allocated various colors to distinguish the objects seen from the reference point.

The percentage of visible layers seen (Sky, Ground and Landscape) are shown on the right hand side. The average shortest distance and horizontal sight angle are shown as well.

The chart shows the % of view taken by distance to view in each band.

1. Open preview dialogue (MBSPreview command in AutoCAD).
2. Click on the relevant Regulation tab and select the calculation.
3. In the Entities Selection section, choose the relevant group or select the entities (Room/Window/Amentity) from the model you are interested in.
4. Next, click Preview.

1. Open Export dialog (MBSExport command in AutoCAD).
2. Click on the relevant regulation.
3. Select the tick boxes next to the calculation name to be exported.
4. Use a Group from the dropdown or Select entities whose results need to be exported.
5. VSC and APSH results are exported in the same sheet for the (default) report and use the VSC group. Bespoke reports may vary.
6. Click Export CSV or Export Excel based on your requirements.

The ExtractRoomSurfaces command is a utility command in AutoCAD that automatically extracts floors, walls and ceilings and put them in corresponding layers.

1. Make sure rooms and windows are registered for the building that you want to assign material.
2. Type the command name in command bar and press Enter.
3. It asks to “select buildings, rooms and windows”. Select the building, together with all the rooms and windows on this building and press Enter
4. Once the command is done, three layers “walls”, “floors” and “ceilings” in different colors are created which contains all corresponding objects.

Know issues and limitations with this command:

• any type of object is supported including solid, 3d face or mesh
• as it uses ray-casting approach to detect surfaces, it assumes the model has already been converted through the Run dialogue.
• assumes the model is light tied. That is internal walls between rooms, floors and ceilings do exist in the model. It does not create any walls or ceilings.
• A single object can only get one material for both back and front face. Therefore if there is no wall thickness, the object will go into indoor(wall, floor or ceiling) layer and would be assigned a material respectably.
• Window bars and frames are not detected and based on the orientation they would go in either of floor, wall or ceiling layers. A manual process is required to set frames and bars in correct layer.

Although this command does most of the job, there must be a QA process to review the output and to check if objects has been assigned to correct layer.