VisualDOE FAQ

Contents

PROJECT (click to see questions)

BLOCKS

• How do I create a 'Custom Block'?
• What are the rules and restrictions for creating 'Custom Blocks'?
• How do I edit a 'Custom Block'?
• How do I create a DXF file for importing blocks into VisualDOE?
• How do I import a DXF file?
• I get an error when importing blocks from a DXF file?
• I am running into an 'Assertion failed:(area*tot_angle>0)[] (abs(abs(tot_angle>-M_PI*2.0)>0.0001),file poly.cpp line 229)' error when I run the simulation.
• How do I copy and paste blocks?
• How can I put several blocks on the same level?
• I have input a floor multiplier but I don't see the extra blocks in the blocks list?
• What is the difference between a floor and an interior floor?
• How do I create a roof?
• If block is on the lower floor why do I still have to select a roof construction?
• Can I create sloping roofs?
• What is a plenum?
• How do I move a block to another location?
• When I combine several blocks to make a building, does the program know when two sides are adjacent to each other to model it as an internal zone or do I need to indicate that somewhere?
• No blocks are created when I drop a standard block.

SYSTEMS (click to see questions)

PLANT (click to see questions)

ORGANIZERS AND EDITORS (click to see questions)

3D VIEWER (click to see questions)

RUNNING SIMULATIONS (click to see questions)

GENERAL (click to see questions)

GLOSSARY OF TERMS (click to see questions)

Blocks

• How do I create a 'Custom Block'?

You can create a custom block by dropping the custom block icon (hexagon) on the plan views. This launches the 'Custom Block Editor' enabling you to create a new block using CADD features.

You create a custom block by adding rooms one at a time. Rooms can be created by drawing them as a rectangle or a polygon, by entering the X Y coordinates, or by importing data from a CADD (DXF) file. The latter approach is useful if you already have a CADD drawing of the building you are modeling and are experienced in using CADD programs.

You can also convert a standard block to a custom block by selecting it and choosing Edit | Custom Block. When a standard block has been converted to a custom block, you can merge rooms, delete rooms, relocate vertices, and perform other custom block functions. Once converted, however, you loose the convenience of being able to change the overall dimensions of the block and have all the rooms change shape accordingly.

The Custom Block Editor has a large drawing area on the left side of the form that is used to draw the outline of each of the rooms that make up a block. The process of creating a block is as follows:

Step	VisualDOE Response
Choose the	A form will be launched where you can set the grid settings. Enter the grid spacing and snap-to-grid resolution that you want to work with.
Choose and then to turn on Snap-to-Grid.	As you move the mouse over the drawing space the coordinates displayed in the status bar will "jump" to the nearest snap-to-grid resolution.
Choose and then and zoom to the portion of the drawing where you want to add a room.	As you drag the mouse, an outline will appear showing the rectangular area you are zooming to.
Choose and then to add a room by creating a two-point rectangle.	As you drag the mouse over the drawing space an outline will appear showing you the size of the rectangular shaped room you are creating.
Choose and then to add a room by creating a polygon.	Click once with the mouse to set a vertex of the polygon. As you move the mouse to another position, a "rubber band" will appear showing the line segment you are about to create. Click again to set another vertex. Click with the right mouse button to close the polygon.

• What are the rules and restrictions for creating 'Custom Blocks'?

The following rules must be followed when creating a custom block:

• The rooms that make up the block must be contiguous and together they must form a regular polygon, e.g. the overall block polygon can't have holes.
• Vertices that define adjacent zones must be perfectly aligned with each other.

• How do I edit a 'Custom Block'?

After a custom block has been created, it can be subsequently edited. There are several editing functions that you can perform:

1. Move the custom block in its entirety. To do this, choose the (Move Block) tool. Click anywhere on the custom block and drag it to the new location. If Snap-to-Grid is on, the behavior of this tool is affected by the Grid Settings and by the status of Snap-to-Grid.
2. Rotate a custom block. Choose the (Rotate Block) tool. The first step is the mark the pivot point around which you want to rotate the block. Click once with the mouse to do this. The second step is to hold down the left mouse key and drag until the block is rotated to where you want it to be. When you release the mouse, the block will be rotated to the new position. If Snap-to-Grid is on, the block is rotated to the nearest Snap Angle as you drag the mouse.
3. Move a vertex. Choose the (Move Vertex) tool. All the vertices will be displayed. Click on the one you want to move, hold down the mouse and drag it to the new position. When you release the mouse the custom block will be reconfigured. When you drag a vertex, you can’t create a self-intersecting polygon or violate any of the other custom block rules. VisualDOE will check for these and other conditions and display a message if the move is not successful.
4. Delete a vertex. Choose the (Select Vertex) tool and select the vertex that you want to delete. Then choose the (Delete Vertex) tool. VisualDOE will then attempt to delete the vertex. If the operation is not successful, a message will be displayed. A vertex can't be deleted if it adjoins two or more rooms.
5. Delete a room. Choose the (Select Room) tool and select the room that you want to delete. Then chose the (Delete Room) tool. VisualDOE will then attempt to delete the room. If deleting the room violates the custom block rules, then the operation fails and a message is displayed for the user. The Delete Room tool is enabled when one and only room is selected.
6. Combine rooms. Choose the (Select Room) tool and select the two rooms that you want to combine. Then chose the (Combine Rooms) tool. The 'combine rooms' tool is visible only when two rooms are selected.
7. Relocate the daylighting reference point(s). Choose the (Move Daylight Reference Point(s)) tool. With this tool, select a room, which will be come highlighted. The daylight reference points within the room will also be displayed. Click on one of the daylight reference points and drag it to a new location. Each room has two daylight reference points, which are shown in different colors. The status bar tells you which one you are moving.
8. Insert a vertex. Choose the (Insert Vertex) tool. Click on the line segment where you want to insert the vertex. Once the vertex has been added, you can relocate it using the (Move Vertex) tool.
9. Edit room coordinates. Choose the (Select Room) tool and select the room that you want to edit. Then chose the (Edit Room) tool. This will cause a spreadsheet like control to appear with the coordinates of the selected room. Modify the coordinates within the spreadsheet control. The Edit Room tool is enabled only when a single room is selected.

• How do I create a DXF file for importing blocks into VisualDOE?

You can use any CADD program as long as it has the capability to save data as a DXF (ASCII Drawing Exchange Format) file. When using AutoCAD you'll have to save the file as an AutoCAD version 13 DXF file.

1. Create a layer in your CADD drawing file for each block/level you want to import to VisualDOE. Give these layers names that will make sense to you later. An example layer name is 1stFlrZns.
2. On each layer, draw a group of contiguous closed polygons. Each polygon represents a room in your energy model. When you create the closed polygons, make sure that you honor the custom block rules and restrictions.
3. Save your CADD file using an ASCII DXF format. Depending on the units you used to create your CADD drawing, you may want to set a scale factor as you save your DXF file. It is best that the units in your DXF file match the units you are using in VisualDOE, either feet or meters.

• How do I import a DXF file?

Step	VisualDOE Response
Choose and then	Additional controls will appear on the right side of the Custom Block Editor form. These will include list boxes for Layers and Polygons and four command buttons with the captions Open DXF File, Add to Model, Scale Factor, and Leave DXF.
Click the Open DXF File command button to open a CADD file.	The common dialog box will appear. Choose a DXF file and click Open. VisualDOE will then attempt to read the file you selected. If it is successful, the Layers list box will be filled with the layers that appear on the file.
Click the DXF Scale Factor command button if needed to set the conversion factor for importing data.	VisualDOE uses either feet or meters, depending on whether you are working with SI units. The CADD file, however, can use inches, millimeters, or any other units. The scale factor converts the units used on the DXF file to either feet or meters.
Click on the layer that has the closed polygons that you want to import.	An outline of all the closed polygons on the layer will be displayed in the drawing space. The Polygons list box is updated to show the closed polygons located on the layer you just selected. These are labeled Polygon1, Polygon2, etc.
Click on one of the polygons.	The selected polygon is highlighted.
Click the "Add to Model" command button.	The selected polygon is added to the block as a room. When the polygon/zone is added, VisualDOE will check to see that the rules or restrictions have been honored. f they have, VisualDOE will add the room to the block.
Repeat steps 5 and 6 until you have completed construction of your custom block.	An image of your block will be shown in the drawing area.

You may notice that when you select a layer, the caption reads "Add All". If you click this command button before selecting a polygon, VisualDOE will attempt to add all the polygons to the model, essentially, repeating steps 5 and 6 described above. When adding zones from a CADD file, you must add them such that the rules and restrictions are honored at each step along the way. If you have three zones that are side by side as shown below. You can add 1, then 2, then 3, but you cannot add 1 followed by 3, because 1 and 3 by themselves would violate the custom block rules and restrictions. The "Add All" option looks for optional sequences of adding the rooms so that the rules are not violated at each step.

• I get an error when importing blocks from a DXF file?

The most common errors when importing DXF files are:

1. The DXF file format is not compatible with the AutoCAD version 13’s DXF format.
2. The DXF file does not have any polygons. Make sure the zones were created using the polygon command.
3. The scale factor is not set correctly. The maximum size of the block allowed is 30000 ft/m.
4. The 'Add All' command may fail when the order in which the polygons are added, creates surfaces that are not contiguous. In this case you’ll have to add the polygons individually.

• I am running into an 'Assertion failed:(area*tot_angle>0)[] (abs(abs(tot_angle>-M_PI*2.0)>0.0001),file poly.cpp line 229)' error when I run the simulation.

This error occurs if the vertices in the custom block(s) are not correctly snapped. This creates vertices that are not perfectly aligned. To fix this error create a backup of the current project, then edit each of the custom blocks to see if the vertices are perfectly aligned and snapped.

If you can't find it visually, try deleting blocks/zones one at a time and running the model. If it runs after a particular block/zone is deleted then you can fix the problem or redraw the block.

• How do I copy and paste blocks?

VisualDOE's 'Edit' menu has 'Copy Block' and 'Paste Block' items, which get enabled when you are on the 'Blocks' folder and a block is selected. Select a block from the list and click on the relevant menu items to copy and paste.

• How can I put several blocks on the same level?

When adding a new block, VisualDOE prompts you to select a level for it. If you want to add the new block on the same level as an existing block, make sure you the new block doesn’t overlap any other existing blocks on the same level.

You can reposition a block by changing the X and Y coordinates on the block folder. The block can also be moved in the custom block editor by selecting the 'Move Block' tool. If several blocks are to be added to the same level then you should reposition the existing blocks before adding a new one.

• I have input a floor multiplier but I don't see the extra blocks in the blocks list?

When a floor multiplier is entered at the block level, the DOE-2 multiplies the energy use of that block. VisualDOE ensures that the surface areas for roofs, floors and walls are written correctly in the DOE-2 input file. If for example you have a single block with a floor multiplier of 3, VisualDOE will create a roof with 1/3 the area of the current roof and a multiplier of 3 for the space it belongs to. This ensures that when the simulation is run, the roof area is modeled correctly.

• What is the difference between a floor and an interior floor?

Floor:	Lowermost floor of the building.
Int. Floor:	Interior floor between floors in the building.
Roof:	Roof on the topmost floor.
Ceiling:	Internal ceiling in the building.

All of these properties may not be required, but they are assigned for each block.

• How do I create a roof?

The program figures out which blocks have exposed roofs and floors when the simulation is run. For example if there is another room above a room, then the surface between them is created as an "interior floor", if not, a roof is created.

• If block is on the lower floor why do I still have to select a roof construction?

The program figures out which blocks have exposed roofs when the simulation is run. If there is another block above, then the surface between them is the "interior floor" input for the block above. If a block has no exposed roof then the roof construction input is not used.

• Can I create sloping roofs?

VisualDOE is not capable of creating sloping roofs right now. You will have to make that change to the input file using DOE-2 keywords.

• What is a plenum?

The space between the ceiling of one floor and the surface of the floor above. HVAC ducts, VAV boxes, pipes, lighting fixtures and other building equipment is generally located in the plenum space. HVAC systems with air distribution can use the plenum for returning air to the fan system.

• How do I move a block to another location?

You can reposition a block by changing the X and Y coordinates on the block folder. The block can also be moved in the custom block editor by selecting the 'Move Block' tool. If several blocks are to be added to the same level then you should reposition the existing blocks before adding a new one.

• When I combine several blocks to make a building, does the program know when two sides are adjacent to each other to model it as an internal zone or do I need to indicate that somewhere?

When two blocks are adjacent to each other the common surface is still modeled as an exterior wall in VisualDOE. You will have to specify an adiabatic construction to these surfaces in order to model them accurately. Create a new construction with a very high R- value (R 1000 will do) and assign it to the common walls of both the blocks. You should also make sure that there are no openings on these surfaces.

• No blocks are created when I drop a standard block.

The default zoning is set to "Custom Block". This allows only custom blocks to be added to the model. Change the default zoning to Interior/Perimeter by editing the default block.