2 Class SummaryThis class will present example projects to demonstrate appropriate techniques for creating Revit models and families for energy analysis purposes:Autodesk San Rafael HQ 111 McInnis Building – Revit model for the creating of DOE2 energy modelsRebuild Sudan’s South Sudanese Primary School project – BIM geometry for daylighting and CFD analysis in Autodesk® Ecotect® Analysis and Simulation CFDRevit Families of Servers for Facebook’s Data Center Designs – Revit families tha are being created to represent Facebook’s servers and connect their models to a databases and spreadsheets through DB Link and the Revit APIMention going through the power point and then doing a live demo.Also check out the handout as it goes into much greater detail on how to create the BIM models and Revit Families.
3 Learning Objectives At the end of this class, you will be able to: Setup project template files to expedite analysis processesCreate BIM geometry for us in energy, daylighting and CFD modelsCreate Revit families that can connect to databases and spreadsheets through Revit’s DB Link and API.Link a BIM model to databases and spreadsheets
4 Autodesk University 2012 Power Track Energy Optimization for RetrofitsMP3397-P - Taking Advantage of BIM for CFD ModelingMP3565-P - Using a Retro-BIM Workflow: Case Studies in Energy-Driven Retrofit ProjectsMP3765-P - Using BIM to Streamline Your Energy Modeling WorkflowsMP3784-P - Calibrating an Existing Building Energy Model
6 Revit Families – Walls, Floors, and Roofs Create exterior an interior walls with a standard thickness (i.e. 6”) to facilitate alignmentSpecify the FunctionEach envelope property should have a distinct material and color for identification purposesDo the same for exterior floors, interior floors and roofsEach material should have a distinct and identifiable nameAdd a descriptive text to the Type Comments field for filter views
7 Metal Roofs, Ceilings, and Shading Devices Use a ceiling family with no thickness for metal roofs if you use the model to create a CFD modelCreate a family type for the walls for the vertical shading device and a family type for roofs for horizontal and angled shading devices (thickness doesn’t matter)
8 Windows, Skylights, Doors, and Openings For windows and skylights, create families that are only openings with an extrusion representing the glazing area. Other types may cause errors in energy models and will slow down CFD model run timesUse reference planes to control the dimensions of the openingDoors are unnecessary in energy models (not required if < 10% of overall surface area of the building per ASHRAE 90.1)Use Windows for other openings.
9 ViewsCreate floor plans and 3D views under the Discipline “Architectural” so architectural elements are clearly visible and easier to selectFor larger projects, create a sub-Discipline “Energy Modeling” to group views with the energy analysis geometry in the project treeCreate a view on the ground floor with Orientation set to “True North” to create the geometry in plan view, but have the ability to rotate the project to true North at any time without affecting other views
10 Views Create additional views for the space and HVAC zones Edit the color schemes appropriately
11 Schedule PropertiesAsk if which parameters would you want to list if the design team has the lights and electrical equipment’s power defined in the families?
12 Create 3D Views Create a 3D view for each building component type The views will hide the other building components so you can export them out as a groupAllows you to manipulate the properties of each component for the entire building at the same time
15 BIM for Energy Models General Rules Don’t use rectangular straight wall openings. They’re not space bounding.Don’t allow any gaps between architectural elements. Space object may “leak” and prevent the analysis from running.Don’t use in-place families. Use native tools for envelope components. In-place families don’t translate to the energy analysis program.Don’t include shaft or stairwell openings.Don’t use design options. If you need to show design options, save them as separate models.Don’t include columns, utility shafts or other components that don’t bind occupiable spaces.Don’t include doors unless they cover more than 10% of the exterior surface area.Don’t use space or room separation lines. They’re difficult to align in floor by floor and usually lead to geometry errors.
16 Energy Model SettingsBefore any export is done, certain settings must be checked:Volumes and Areas must be turned onEdit the Energy settings (Analyze>>Energy Analysis>>Energy Settings)Set Ground Plane.Set Project Phase. Spaces must be placed in the same phase as the Project Information phase.Energy Export Complexity set to Simple with Shading Surfaces. The limit of shading surfaces in the model is 1024.Set Sliver Space Tolerance. Leave the default value of 1’ 0”.Note: Thermal performance characteristics of elements in the Revit physical model aren’t carried through to the energy analysis programs
18 WallsExterior walls should start at the ground level and extend to the roof, or another upper bounding elementUse constant thickness, different thicknesses will give you errors in your modelModel spandrel glazing as an exterior wallUse interior walls to define HVAC zones on a floor by floor basis
19 More on Walls and Shading Devices Don’t use interior walls as exterior walls, they won’t show up in your energy modeling programModel underground walls separately and make sure neither the underground wall nor the exterior wall crosses the ground planeModel curved walls as a series of straight walls and windowsModel shading devices as rectangles; use exterior walls to represent vertical shading devices and roofs for horizontal and angled shading devices
20 Roofs Roofs should all be the same thickness as floors Offset roofs properly to that a single space could encompass the entire roof and floor slab properlyRoof should be offset by its thickness
21 Floors Floors should all be one thickness Floor boundaries should either be the center line, or the interior surface of the exterior wallsFloors should be at the same elevation as the spaceAny floor extending beyond an exterior wall should be modeled in two separate pieces; a floor inside the wall and a roof outsideModel slab on grades as exterior floors
23 CeilingsOnly use ceilings when the HVAC system type utilizes the stratification effect (i.e. UFAD or displacement ventilation)Add ceiling above the occupied volume (usually ~7’)Set the space below the ceiling as occupied and above as plenumAsk does anybody know why this would impact the efficiency of your HVAC system?
24 SpacesAdd one space, set the space number format and provide a common space type name (i.e. “office”).Set the height of the space to the level above if there are interior spaces on the above floorIf the upper boundary is a roof, the top surface of the space must be offset by the thickness of the roof to avoid adding unnecessary shading devices to the model
25 SpacesFor UFAD or displacement ventilation, the top surface must align to the ceilingAdd a tag, select it and the space, and use Revit Copy (not Ctrl+C)Revit will use the same space name and will try to guess the next space number/letter; numbers/letters will increaseEdit space types accordingly (i.e. non “office” spaces)Use the Paste Aligned feature to copy similar space layouts from one floor to another
26 Spaces Under space properties, Select whether the space is occupiable Select the Conditioning TypeEdit Occupancy (People)Edit Electrical LoadsAlternatively, you can use the grouped space schedule to control the parameters for a particular space type
27 Zones Must add an HVAC zone for each space Use the same numerical value as space numberRecommended to add an abbreviation for the space type in the zone name
28 Zone Properties Edit the Outdoor Air information Can edit heating/cooling setpoint temperatures, but generally easier to edit these in the energy modeling tool
30 TroubleshootingWhen uploading the gbXML file created in Revit to GBS, GBS may crash and not successfully upload your modelOften, the error message won’t provide any assistance in identifying the origin of the errorTo find the error in your Revit model, employ a method called “Divide and Conquer”Start by splitting the building in half and try uploading each side to GBSWhichever side crashes while uploading to GBS, continue splitting the model and repeat the process until you find the errorIf both sides of the model crash GBS, change where you split the model.
31 Creating a DOE2 Energy Model There are two classes at this Autodesk University the focus on the creating of a DOE2 energy model in eQUEST:MP3765-P Using BIM to Streamline Your Energy Model Workflows by Jeff OldenMP3784-P Calibrating an Existing Building Energy Model by Lauren Kuntz
33 BIM Geometry for Daylighting Many projects can use the geometry created for the energy model to create a daylighting model.In some situations, the geometry needs to more accurately represent the physical layout of the space within a building:Slanted or other non-horizontal ceilings used for daylighting or other architectural purposesSpaces with daylighting shelvesProjects where the impacts of furniture need to be taken into considerationFor these, create a separate Revit model and modify it accordinglyThe rest of the process will remain the same
34 Adding a Slanted Ceiling Create a level at the lowest point of the ceiling and an associated viewIn that view, click on “Place Ceiling” under the Architectural tabSet the offset to 0’ and select the top boundary of the ceiling to set the slopeEdit the slope designed at the boundary and finish the ceilingCheck in a section view to see if it has been modeled correctly; you may need to go back and edit either the ceiling’s slope or offset
35 Model Setup in Revit for Daylighting In Revit, think about how the model is going to be used and how the geometry should be created to support that outcomeFor daylighting, utilize the series of 3D views of the various building components created in the template file to isolate like materials for exporting to FBX files.Understand the appropriate level of detail needed in the Ecotect modelGive consideration to the amount of curved/rounded objects in a model; affects file sizes and time to import geometryConsider how these items impact furniture/major fixed equipment and file size of your model
37 Exporting to 3ds Max Design In the Application pulldown menu in Revit, select Export > FBXThis will export out each 3D view of like materials into an individual FBX file
38 Model Setup: 3ds Max Design Currently, 3ds Max Design is a translator for the FBX file exported from Revit to a 3DS file imported into Ecotect AnalysisBefore importing/exporting the models, ensure the project units are set up correctlyFrom the Customize pulldown menu, select Units Setup:Set Display Units Scale to US Standard:Feet w/Fractional Inches1/32Set System Units Setup1 Unit – 1.0 Feet
39 Model Setup: 3ds Max Design To import the FBX models, go to the Application pulldown menu, select Import>>Import and set Files of Type to Autodesk (*.FBX) and hit OK when the FBX Import dialog box pops upTo export, go back to the Application pulldown menu, select Export>>Export and set Save Type to 3D Studio (*.3DS) and hit saveIn the dialog popup, uncheck the box for “Preserve Max Texture Coordinates”
40 Ecotect Analysis Model Imports To import the geometry from the .3DS file created in 3ds Max Design, go to:File>Import>3D CAD Geometry…Files of Type: 3D Studio (*3DS, *ASC, *PRJ)Remove Duplicate FacesAuto Merge TrianglesScale Objects By: Feet >Millimeters (304.8)Material – Leave it set to <<Guess>>Zone – Leave it set to <<File>>Import Into Existing
41 Model Setup in EcotectMay need to redefine the origins of your model geometry in EcotectThis requires defining the ground plane:Use the “Set Origin” button in the toolbarDefine a point in the model to serve as the origin“Reset World Origin”Go to the Modify pulldown menuSelect Transform OriginReset World OriginIf you didn’t specify True North in Revit, do so in theProject Page
42 Material AssignmentsTo apply the specific material that has been created, go to the 3D Editor PageIn the Zone Management Panel:Right click on a zone in the modelRight click and choose “Select Objects On”In the Material Assignments Panel:Select the appropriate materialSelect Apply Changes**To learn how to complete a daylighting model using Ecotect and Radiance, refer to the 2011 AU class MP4568-P by Brian Skripac
44 BIM Geometry for CFD Models Anything hidden in active 3D view won’t be included in Simulation CFDUse visibility graphics or the hide tool to hide categories of elementsAvoid small offsets between geometry; use join and align to eliminate small gapsColumns and beams can generally be omittedFine features on furniture should be excluded (i.e. small diameter tubing, railings, rounds, fillets, holes, etc.)All models need a surrounding mass volume to represent the air surrounding a building
45 Wind Driven ModelsWhere do you think the wind is coming from?
46 Buoyancy Driven Models Does anybody know what a buoyancy driven model is?
47 Revit to Simulation CFD Go to the 3D view where you want to use as the basis for the CFD modelGo to the Add-ins Tab and Launch Active ModelAlternatively, you can export the view’s geometry as the .sat type of CAD file and import it into Simulation CFD or Simulation CFD 360**To learn how to complete a CFD model using Sim CFD 360, refer to the 2012 AU class MP3397-P Taking Advantage of BIM for CFD Modeling.
48 Revit Families for Linking to Databases and Spreadsheets
49 Building Revit Families Refer to Revit’s Wiki help for detailed documentation on how to create Revit FamiliesUse Reference planes and Dimension Labels to adjust the dimensions of geometry
50 Connecting to an Access Database Refer to Revit’s Wiki help for detailed documentation on how to install and use DB LinkUse Reference planes and Dimension Labels to adjust the dimensions of geometryLimited selection of parameters that are editable in the database.