ConstructDXF User Guide
<Virtual Environment> 6.0
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Contents
1.
Introduction ....................................................................................................... 3
1.1.
What is ConstructDXF? ........................................................................................................ 3
1.2.
Before Using ConstructDXF ................................................................................................. 4
1.3.
Conventions Used in this Manual......................................................................................... 4
1.3.1.
Click ............................................................................................................................. 4
1.3.2.
Select ........................................................................................................................... 4
1.3.3.
Checking/Unchecking .................................................................................................. 4
2.
Using ConstructDXF ......................................................................................... 5
2.1.
How ConstructDXF Works ................................................................................................... 5
2.2.
Preparation of the DXF Drawing .......................................................................................... 5
2.3.
Setting Up Room Templates Using the Building Template Manager .................................. 6
2.4.
Starting ConstructDXF ......................................................................................................... 6
2.5.
ConstructDXF Rules ............................................................................................................ 7
2.5.1.
Basic Rules .................................................................................................................. 7
2.5.2.
Room Names ............................................................................................................... 7
2.5.3.
Voids ............................................................................................................................ 8
2.5.4.
Continuous Vertical Stacked Spaces .......................................................................... 8
2.5.5.
Windows ...................................................................................................................... 8
2.5.6.
Doors ........................................................................................................................... 8
2.6.
A Quick Guide to Generating a ConstructDXF Model .......................................................... 8
3.
The ConstructDXF Window............................................................................ 10
3.1.
Settings .............................................................................................................................. 11
3.1.1.
Settings - Tolerances Tab ......................................................................................... 11
3.1.2.
Settings - Line Combination Tab ............................................................................... 12
3.1.3.
Settings - Heights Tab ............................................................................................... 13
3.1.4.
Settings - Doors Tab.................................................................................................. 14
3.1.5.
Settings - Windows Tab............................................................................................. 15
3.1.6.
Settings - Key Labels Tab ......................................................................................... 16
3.1.7.
Settings – Room Templates Tab ............................................................................... 17
3.2.
Extract ................................................................................................................................ 19
4.
5.
Modifying the 3D Model.................................................................................. 20
Performing Calculations ................................................................................ 20
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1. Introduction
1.1. What is ConstructDXF?
ConstructDXF is used to produce data for IES’s thermal, shading analysis,
lighting and building design appraisal software by scanning ordinary DXF
drawings of building plan layouts, and generating a 3D building data model,
within the ModelIT environment. ConstructDXF simplifies and accelerates the
preparation of data for a wide range of building design studies including
thermal design, shadow modelling, dynamic thermal simulation, multi-zone
airflow analyses and electric lighting/daylighting studies.
ConstructDXF is run from within ModelIT (IES’s 3D modelling tool). The two
programs together provide the user with a comprehensive set of tools to allow
the generation of a full three-dimensional spatial building model and
associated non-graphical attribute data from DXF format drawings. The familiar
Windows style interface is used to provide dialogue box data entry for
information unobtainable from the drawing file(s), such as storey, window and
door heights, element constructions, building and room default attributes, and
for the subsequent editing of room and room element data.
The data model can be generated from DXF drawings containing any
conventional drawing element (arcs, shapes, cells, B-splines, etc.). No special
elements or attributes are required. In addition to single floor plans,
ConstructDXF will cater for several buildings on one site, multi-storey buildings,
and buildings that bifurcate as they rise up.
Once the 3D model has been created by ConstructDXF, geometric (and
attribute) modifications or additions can be made to the model if required using
the standard ModelIT facilities. Likewise, models created using ModelIT can be
built further using ConstructDXF (if, for example, you wish to generate an
additional storey from a DXF drawing).
The information from the data model generated by ConstructDXF is used to
generate files for IES’s thermal analysis, shadow analysis, airflow or lighting
software. (Refer to the IES User Guides).
Results from the calculation software are read back into ModelIT and if
required, these results can be viewed within the ModelIT environment.
Additionally, luminaires can be placed and modified in the 3D model either
directly by the user (for subsequent point-by-point analysis by the lighting
calculation software) or as a result of performing a lighting design with the
lighting software.
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1.2. Before Using ConstructDXF
You should have a reasonable level of familiarity with the Windows operating
system in terms of the basic conventions such as window operations
(dragging, resizing, etc.), dialogue boxes, toolbars, file selection etc. If you
don’t, please consult your system manager before attempting to use
ConstructDXF.
You should also be familiar with ModelIT, as ConstructDXF operates within the
ModelIT environment. For detailed information on ModelIT, e.g. menu items,
toolbars and tool button functions and how to modify the model, please refer to
the ModelIT User Guide. Please contact IES if you require training in ModelIT.
1.3. Conventions Used in this Manual
1.3.1. Click
Pressing the left mouse (or data point) button.
1.3.2. Select
Clicking on an element or item so that it is highlighted. It should be noted that after
performing certain operations on a 3D model that has been built (such as adding an
opening), you must first click on the Select Object tool button in the View tool bar
before you can select an element.
1.3.3. Checking/Unchecking
An option may have a check box next to it. To enable the option, check the box, i.e.
click in the box so that a tick or cross appears in it. Clicking in the box again to
remove the tick or cross is known as unchecking.
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2. Using ConstructDXF
2.1. How ConstructDXF Works
The use of ConstructDXF can be broken down into the following basic
operations:
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ModelIT is started and a new (or existing) project is opened.
A drawing file in DXF format is read into ModelIT.
Defaults for the room thermal and lighting data and fabric element
constructions are set by means of room templates.
ConstructDXF is then started within ModelIT.
Extract settings (rules and tolerances) are set, together with default
storey heights for the storey to be generated, and default window and
door heights.
A 3D data model for that storey is then generated (extracted).
If required, another DXF drawing can then be loaded into ModelIT, and
further storeys can be generated.
Within the 3D model, the data for individual rooms and elements can be
modified.
The finalised 3D data model can then be used by the IES thermal and/or
lighting software for calculation purposes.
Calculated luminaires can be added to the 3D model.
2.2. Preparation of the DXF Drawing
First, start ModelIT, and open a new or existing project by selecting New or
Open from the File menu. Next, from the File menu, select Reference Files,
and select Attach DXF File to find and attach your required DXF drawing. The
DXF drawing will then be displayed in the ModelIT window.
Layers (levels) in the DXF file can be switched on or off within ModelIT. To do
this, use the File menu and select Reference Files, then Active DXF Layers.
Layers which contain elements which are not to form part of the building model
(grids, dimensions, furnishing and fitting symbols, etc.) should be turned off.
ConstructDXF is designed to operate on DXF plan view drawings. If required,
the same DXF file may be used for several storeys.
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A DXF drawing in ModelIT
2.3. Setting Up Room Templates Using the Building Template
Manager
ConstructDXF uses room templates, which contain defaults for both
construction and non-graphical attribute data (lighting, thermal, casual gains,
air exchange, etc). The available templates are shown in the drop down list in
the dialogue bar at the bottom of the ModelIT window.
Templates are created and edited using the Building Template Manager utility,
which is accessed via the Templates menu on the <VE> menu bar (see the
Building Template Manager User Guide for further information).
Note that you do not have to use the Building Template Manager before you
generate a model. If you have no attribute information, just use the ‘default’
template. Rooms that are generated will be assigned default attributes, and
you can then modify the attributes of each room individually when you have the
correct attribute information.
2.4. Starting ConstructDXF
Select ConstructDXF from the Utilities menu. The ConstructDXF window will
appear within the ModelIT environment.
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The ConstructDXF window within ModelIT
2.5. ConstructDXF Rules
In building a 3D model from the DXF information, ConstructDXF applies a
number of rules which are summarised in this section.
2.5.1. Basic Rules
ConstructDXF applies three basic rules to each DXF file in order to identify building
perimeters, room perimeters and bordering elements including roofs, ceilings,
internal floors, ground floors, external walls and internal partitions:
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Rule 1 - Each building on a site must have a closed external loop which may
incorporate door symbols and window symbols (see Windows and Doors
below).
Rule 2 - All internal spaces or rooms must have a closed internal loop which
may include door and window symbols (see Windows and Doors below). The
internal loop may be composed of the same elements as the external loop.
Rule 3 - All rooms must have one label located within the room perimeter.
2.5.2. Room Names
All rooms to be included in the model should have one label located within the space
and with its origin not contained within a confining element. ConstructDXF will
recognise the existence of multiple labels within one room but this will significantly
increase the processing time and therefore any unnecessary text should be
removed.
Note origins of text labels must not lie within the thickness of a wall.
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2.5.3. Voids
Spaces within the perimeter of a building that represent external spaces will be
recognised if the name matches the Void Label which is set under the AutoExtract
Settings (see Settings).
2.5.4. Continuous Vertical Stacked Spaces
Any space that is continuously joined with another space above or below will be
correctly identified if the name matches the Stack Label set under the AutoExtract
Settings (see Settings).
2.5.5. Windows
Window symbols are identified using the following hierarchical rules:
1.
2.
3.
Any element found on a drawing layer (level) specified as a Window layer in
the AutoExtract Settings.
Any sequence of elements forming an overlaid or indented rectangle within
an external wall.
A number of parallel lines within an external wall element. This number must
be greater than or equal to the Minimum Number of Window Lines setting for
the identification of a window.
Window rules also take into account the dimensions entered under the AutoExtract
Settings.
See Settings for more details.
2.5.6. Doors
Doors may be represented using two lines at an angle of between 30 degrees and
60 degrees to each other or a 90-degree swept arc. Small line segments included
within a door symbol will automatically be ignored. Doors are included within the
model in the closed position. Door rules also take into account the dimensions
entered under the AutoExtract Settings.
See Settings for more details.
2.6. A Quick Guide to Generating a ConstructDXF Model
Start ModelIT and create a new project by selecting ‘New’ from the File pull
down menu.
Attach a DXF drawing using the Reference Files option from the File menu.
Turn off all unnecessary layers in the drawing.
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Start ConstructDXF. Check that the extract settings are appropriate for the
current DXF file then click on the Extract button to generate the data model.
The model generation progress will be displayed on a completion bar.
The process may be aborted at any stage by pressing the Cancel button.
When the extract process is complete, the generated building model data is
written to a model project file with the extension *.mit. This file holds both
geometric or spatial data and non-graphical attribute data.
When you close ConstructDXF, the ModelIT facilities that allow you to modify
the data model are now enabled.
If required, another DXF drawing can then be loaded into ModelIT, and further
storeys can be generated.
The attribute data for each room may be viewed and edited by clicking on the
Query button in ModelIT. The construction and dimensions of various elements
may be viewed and modified by clicking on the Query button.
Once the model has been generated and the room and room element data
have been edited as required, you can then run the various IES programs by
selecting the appropriate program from the Applications menu.
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3. The ConstructDXF Window
The ConstructDXF window is where extract settings are specified, and from
where the model is generated.
Note that some of the facilities in ModelIT will be disabled until you have
generated a 3D model.
When ConstructDXF is first started, the ConstructDXF window displays the
model view which is comprised of the current DXF drawing and the 3D model (if
it has been generated).
The ConstructDXF window showing the DXF drawing
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3.1. Settings
Clicking on the Settings button in ConstructDXF opens the Settings dialogue
box, which is split into tabbed sections.
3.1.1. Settings - Tolerances Tab
This contains controls to set various tolerances used during the model generation
process.
Settings - Tolerances tab
3.1.1.1. Max Arc-Chord Distance
ConstructDXF will convert all arcs and curves into series of straight lines or vectors. The
arc-chord distance is the maximum distance between the resulting vectors and the actual
line. A very small arc-chord distance will result in a very accurate representation of the arc
or curve but will result in a longer processing time and conversely a large arc-chord
distance will produce a less accurate model but much faster processing times. Any arc
having a radius within the minimum-maximum door width range will automatically be
converted to a single straight line.
3.1.1.2. Line Extension
Having extracted all drawing elements from the DXF file, ConstructDXF then converts all
elements into series of lines or vectors. In order to cater for drafting inaccuracies or errors
in file translation, an extension may be added to the ends of all vectors to ensure that lines
that should meet do actually meet. Be careful when applying extensions not to inadvertently
cause lines to be joined which should be kept separate.
3.1.1.3. Maximum Horizontal Separation
This allows you to identify horizontal room adjacencies. This value should be set to slightly
greater than the maximum wall thickness as it appears in the drawing.
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If the distance between one space and another space (after model extraction) is less than
this value, the two spaces are deemed to be adjacent to one another, i.e. the facing
elements of each space are the same connecting partition.
If the distance between the two spaces is greater than the adjacency separation distance,
then the two spaces are deemed to be independent of each other, i.e. the facing elements
of each space are exterior walls.
3.1.1.4. Maximum Vertical Separation
This allows you to identify vertical room adjacencies. This value should be set to slightly
greater than the maximum slab thickness (including floor and ceiling depths).
3.1.2. Settings - Line Combination Tab
During the model generation process, any lines or vectors which are considered to
be parallel and touching will be combined into a single vector. The Line Combination
tab contains the tolerancing controls for determining whether or not lines should be
combined.
Settings - Line Combination tab
3.1.2.1. Connecting Angle
Two lines will be considered parallel if they meet at an angle between the Connecting Angle
and 180 degrees.
3.1.2.2. Max. Separation
The maximum distance between two lines, below which the lines are considered to be
touching.
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3.1.3. Settings - Heights Tab
This tab is used to set default heights for the automatic model generation.
Settings - Heights tab
3.1.3.1. Base Plane
The base plane is the point in the model Z (height) plane from which the storey will be
extruded.
3.1.3.2. Storey Height
The storey height is defined as the distance between the finished floor level and the
finished ceiling level (i.e. the useable room height).
3.1.3.3. Window Cill Height
The default window cill height is the height of the window cills from the finished floor level.
3.1.3.4. Window Height
This is the default window height above the cill height.
3.1.3.5. Door Height
This is the default height of doors above the finished floor level.
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3.1.4. Settings - Doors Tab
This tab contains controls that are used to set tolerances for the identification of door
symbols in the drawing.
Settings - Doors tab
3.1.4.1. Min. Door Width
Doors may be represented using two lines at an angle of between 30 degrees and 60
degrees to each other or a 90-degree swept arc. If the line representing the door (as
opposed to the sweep) is less than the minimum door width, the symbol will not be
interpreted as a door.
3.1.4.2. Max. Door Width
Doors may be represented using two lines at an angle of between 30 degrees and 60
degrees to each other or a 90-degree swept arc. If the line representing the door (as
opposed to the sweep) is greater than the maximum door width, the symbol will not be
interpreted as a door.
3.1.4.3. Max. Door Recess Depth
This tolerance caters for cases where the door symbol has been draughted such that the
door panel line originates from one point relative to the wall (e.g. the inner surface of the
wall), and where the door swing line or arc originates from another point relative to the wall
(e.g. the outer surface of the wall, or within the room).
This may occur where the intersection of a double door symbol extends beyond the wall
plane.
If the distance (perpendicular to the wall) between these two points is greater than the
maximum door thickness, the symbol will not be interpreted as a door.
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3.1.4.4. Min. Wall Length
If the length of a wall element is less than the minimum wall length, ConstructDXF will not
identify this element as a wall. ConstructDXF also uses this tolerance in the identification of
door elements. If door symbols contain details such as the thickness of a door, make sure
that the minimum wall length is greater than the maximum length of all detail lines.
3.1.5. Settings - Windows Tab
This tab contains controls that are used to set tolerances for the identification of
window symbols.
Window symbols are identified using the following hierarchical rules:
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Any element found on a drawing layer (level) specified in the Layer box.
Any sequence of elements forming an overlaid or indented rectangle within
an external wall.
A number of parallel lines within an external wall element. This number must
be greater than or equal to the Minimum Number of Lines setting for the
identification of a window.
Settings - Windows tab
3.1.5.1. Min. Width
A window symbol will not be interpreted as a window if its width is less than the minimum
window width.
3.1.5.2. Max. Width
A window symbol will not be interpreted as a window if its width is greater than the
maximum window width.
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3.1.5.3. Max. Offset
A window may be represented by a rectangle overlaying or indented within an external wall
element. If the offset or indent of the rectangle sides from the parallel wall surfaces is
greater than the maximum window offset, it will not be interpreted as a window.
3.1.5.4. Min. No of Lines
This is the minimum number of parallel lines that have to be drawn for a window element,
for that element to be identified as a window.
3.1.5.5. Layer
If a drawing layer is selected for a search, ConstructDXF looks for windows on the DXF
drawing layer (or level) that is selected. If you do not wish to search on other layers, select
‘No Layer Search’.
3.1.6. Settings - Key Labels Tab
String patterns are entered here. They are used in the extraction process to identify
spaces that are to be treated as void or stacked spaces, by analysing the text in the
rooms in the DXF file. Stacked spaces only apply to multi-storey models.
Settings - Key Labels tab
3.1.6.1. Void
This is used to define a search string pattern for external spaces within a building perimeter,
e.g. courtyards, light-wells, etc. Any room having a name, which complies with the void
space search string pattern, will be considered an external space (e.g. courtyard). The
string may contain wild-card characters (* and ?). For example to include all rooms
containing the string 'court', you would type in ‘*court*’. More than one key label can be
defined by using a semicolon to separate the labels.
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3.1.6.2. Stacked
This is used to define a search string pattern for spaces that are vertically continuous. Any
room having a name, which complies with the stacked space search string pattern, will be
considered a vertically stacked space (e.g. stairwell). The string may contain wild-card
characters (* and ?). For example to include all rooms containing the string 'stair', you
would type in ‘*stair*’. More than one key label can be defined by using a semicolon to
separate the labels.
The default values set up in these Settings tabs are the result of extensive application and
have been found to be appropriate for most cases. Consequently, if you are uncertain of
which values to use for a drawing file, try generating a model using the default values and
then modify them if necessary.
Check that the minimum/maximum door range and minimum window length and maximum
window offset cover all occurrences in the drawing.
When you have entered the required data in all the above tabs, press OK to update the
Settings. The Settings dialogue box will then close.
3.1.7. Settings – Room Templates Tab
The room templates tab lets the user select which template is to be applied to all the
zones constructed from the DXF drawing. Templates allow for easy designation of
common zone features and conditions when constructing a <VE> model. Only one
template for each category can be assigned to all the zones during a ConstructDXF
operation. More information on templates can be found in the Building Template
Manager user guide.
Settings – Room Templates tab
3.1.7.1. Room Attributes Template
This section allows the user to set the percentage of floor area that is lettable or circulation.
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3.1.7.2. Constructions Template
This section is where the opaque and glazed constructions are specified for templates.
3.1.7.3. MacroFlo Opening Types Template
This section is where the MacroFlo opening types are assigned to templates. The opening
types available are:
•
Rooflight
•
External Glazing
•
Internal Glazing
•
Door.
3.1.7.4. Thermal Conditions Template
This section is where room thermal conditions are assigned to templates. There are four
tabs for thermal conditions data (five if Building Regulations are enabled):
•
Building Regs (optional)
•
Heating
•
Cooling
•
Casual Gains
•
Air Exchanges
.
3.1.7.5. Electric Lighting Template
This section allows electric lighting data to be assigned to templates used by programs
within the <VE> Lighting section.
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3.2. Extract
Clicking on the Extract button initiates the model generation process which is
displayed on a percentage completion bar. The process may be aborted at any
stage by clicking on the Cancel button.
When the Extract process is complete, you will see the generated model in
both the ModelIT window and in the ConstructDXF window.
A generated model
If required, another DXF drawing can then be loaded into ModelIT, and further
storeys can be generated. To do this, close ConstructDXF, then use the
Reference Files option from the File menu to attach the next DXF file. Then
start ConstructDXF again. Before you extract the next storey, make sure that
the value of the Base Plane in the Heights tab of the Settings dialogue box is
equal to or greater than the Z value of the top of the current storey.
Note that you need to close the ConstructDXF window before you can use any
of the ModelIT facilities.
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4. Modifying the 3D Model
Once the model has been generated, you may use the standard ModelIT
techniques to modify the thermal, lighting and construction attributes for a single
room or a selected group of rooms. You may also add rooms or draw pitched
roof constructions using the ModelIT drawing tools. See the ModelIT User
Guide for further information.
Note that you need to close the ConstructDXF window before you can use any
of the ModelIT facilities.
Use the Building option from the Settings menu in ModelIT to define the building
rotation for thermal and shading calculations.
Use the APlocate utility to set up site and weather data for thermal and shading
calculations (see the APlocate User Guide).
5. Performing Calculations
Having created a model, any of the <Virtual Environment> modules may be
used in conjunction with the model.
Select the module you wish to run from the Applications Selector:
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