Microsoft Word - MP1294 - Making Full Use of the Power of Lookup Tables

Making Full Use of the Power of Lookup Tables

Kelli Lubeley – Enceptia

Elizabeth Mierendorf – Dewberry

MP1294 This class shows users how Autodesk® Revit® MEP building design software uses lookup tables to

automatically size pipe, conduit, and cable tray fittings properly. We look at how lookup tables are formatted and how

the Revit family references the lookup table. Users will better understand the role of lookup tables in Revit and be able

to use lookup tables when creating and editing families

LearningObjectives

At the end of this class, you will be able to:

 Identify and describe the concepts behind lookup tables and explain how lookup tables benefit the design

process

 Create custom families that reference lookup tables for automated design

 Use formulas with lookup tables for accurate design

 Explain how using lookup tables improves workflow

AbouttheSpeakers

Kelli Lubeley currently works as a technical advisor for Enceptia, an Autodesk gold partner. Her

main focus is on workflow development, content creation, and 3rd party application integration

for Revit Architecture, Revit MEP, and Revit Structure. She has developed and instructed Revit

courses at the community college and corporate level for over 5 years, and implemented Revit

Architecture and MEP at multiple firms. She enjoys the many facets of the Revit platform and

loves to constantly find new ways to leverage BIM technology for the design community.

[email protected]

Elizabeth Mierendorf currently works at Dewberry as a Senior Virtual Design Coordinator. As

part of the Virtual Design Team, she has been involved in all aspects of Dewberry’s BIM

implementation, primarily focusing on Architecture and Interior Design processes.

Elizabeth is responsible for developing efficient BIM workflows, training all architectural staff,

creating and maintaining Revit content, and providing support for all of Dewberry’s architectural

offices. She has been using Autodesk Revit since 2006 and began training others in the

software in 2009. She is passionate about teaching BIM concepts to others and loves helping

them get the most out of their Revit models.

Making Full Use of the Power of Lookup Tables

ConceptandBenefitofLookupTables

Theuseoflookuptablesforpipeandconduitfittingsprovideaninvaluableprocessthatwetakefor

granted.Imaginelayingoutapipesystemandgoingthroughtomanuallysetthesizeofeverysingle

fittinginthesystem.Sure,itmightonlytakeafewseconds,butwithhundreds

offittings,itaddsupfast.

Thenofcoursetherearethemultipleredesignsandresizesthroughoutthelifeoftheproject.We’re

talkingdozensofhoursthatlookuptablesaresavingusbyautoma tingfittingsizing.Let’sexplorelookup

tablesandtheirrelationshipwithRevitfamiliestobetterunderstand

thisprocessanditsbenefits.

Lookuptablesare.csv(commaseparatedvalue)filesthatareusedinconjunctionwithRevit.Revituses

specialparametersandformulasinfamiliestoreferencethelookuptableinformation.Lookuptableslet

youspecifymultipleparametervaluesrelativetoanothervaluewithoutcreatingaseparatetype

for

eachsetofvalues.Th e mostcommonuseoflookuptablesisdefiningthevariousdimensionsofpipe

andconduitfitting sbasedontheNominalDiameterofthefitting.Thisrelationshipofthe.csvfileand

theparameters/formulasinthefamilyletsRevitimmediatelysizeandresizefittingsbased 

onthe

segmentstowhichtheyareconnected.

FormattingtheLookupTable

LookuptablescanbeeditedusingMicrosoftExcelorNotepad.Row1containsthecolumnheadersfor

eachcolumn.ColumnheaderformattingisParameterName##ParameterType##ParameterUnits.

Notethe##betweeneachpartofthecolumnheader.



Making Full Use of the Power of Lookup Tables

Thefirstcolumnisareference columnusedtodesignatea“na me”orreferenceforwhatthatrowinthe

tabledefines.Thecolumnheaderforthiscolumnisalwaysleftblank.Thesecondcolumndefinesthe

lookupvalue,typicallythenominaldiameteroftheelement.Thiscolumn

isacomparativecolumnthat

Revittriestomatchdata fr omthefamilytothedatainthiscolu mn.Allremainingcolumnsarelookup

columns,whereRevitwillretrievevaluesbasedonthelookupvaluedatainthefamily.Ifmorethanone

lookupvalueisnecessary,thenasmany 

columnsasneededarecreated,shiftingthelookupcolumns 

over.So,ifyou’recreatingateefittingthathasthreedifferentnominaldiameters,oneforeach

connection,youshouldhavethreelookupvaluecolumnstocoincidetheseparameters.

ReferenceColumn,LookupValue,andLookupColumnsinaLookupTable.

Note:Thelookupvalue(s)inthelookuptablemustcorrelatetoaSizetypeparameter(i.e.DuctSize,

PipeSize,etc.).lookupcolumnscanbeanytypethatisnumerical(i.e.Length,Integer,Volume,etc.).

HowRevitFamiliesuseLookupTables

Revitfamiliesmustuseaveryspecificprocesstoaccessandretrieveinformationfromlookuptables.

Thelookuptableisstoredwithinthefamilythroughanimport/exportdialog.Thisfileisthenreferenced

throughatextparameter.Thesetwocomponentsprovidetheaccesstotheinformationinthelookup

table.Then,

aspecialformulaisusedtoretrievevaluesfromthelookuptable.Wewilltakeanin‐depth

lookateachpieceoftheconnectiontounderstandtherelationshipbetweenthefileandhoweach

pieceofinformationisretrievedandutilizedbythefamily. 

ImportingandReferencingtheLookup

Table

Toimportthelookuptable intoyourfamily,intheFamilyTypesdialog,clickontheManage…button

alongtherightsideofthedialogbox.



Making Full Use of the Power of Lookup Tables



IntheManageLookupTablesdialog,clickontheImport…button.Browsetotheappropriatelookup

tablefileandclickOK.



BackintheFamilyTyp es dialog,weaddatextparameternamedLookupTableName.(Thetext

parametercantechnicallybenamedanythingyou

want,buttokeepconsistencywithoutofthebox

familiesandtosimplifyformulas,Irecommendkeepingthestandardname.)Thenenterthenameofthe

.csvfileinthevalueofthisparameter.

Note:TheLookupTableNamevaluemustmatchthe.csvfilenameexactlywithoutthe

.csvextension,

butitisnotcase‐sensi tive.



OncetheLookupTableNameparameterhasbeenfilledin withtheappropriate.csvfilename , the

lookuptablecanbeusedinformulastoreferencethetableforvalues.

UsingFormulaswiththeLookupTable

Aspecificformulaisusedto

referencethelookuptabletoacquirevalues:

Making Full Use of the Power of Lookup Tables

size_lookup(LookupTableName,“LookupColumn”,DefaultIfNotFound,LookupValue)

TotranslatethisintoEn glish,wearetellingRevittogolookin(LookupTableName) foracolumncalled

(lookupcolumn)andreturnthevaluefromthatcolumnthat correspondswith(lookupvalue)row.If



thereisnomatch,returnthevaluespecifiedfor(DefaultIfNotFound). 

Let’slookatanexample:

Inthiscase,theformulaforfindingthevalueofFittingOutsideDiameterreadss omethinglikethis:In

LookupTableName(referstoparameterunderTextwhereyouenteredthe.csvfile

name),lookfora

rowinthelookupvaluecolumnthatcorrespondstothefamily’scurrentvalueofNominalDiameterand

returnthevaluefromcolumn“FOD”inthatrow.IfnomatchisfoundforNominalDiameterinthe

lookupvaluecolumn,retur navalueequaltoNominalDiameter

1+1/8”.

NoticethatNominalDiametercurrentlyhasavalueof1”.Ifwelookatour.csvfile,we’llseethatND,

ourlookupvalue,correspondstoNominalDiameterintheFamilyTypesdialog.WhenNDis1”,FODis

1.125”,or11/8”.Soourfamilywillhave

aFittingOutsideDiametervalueof11/8”.

UsingMultipleLookupValues

Toverifythevaluesofmultipleparameters,additionallookupvaluesareaddedtotheendofthe

formulaandthecorrespondinglookupvaluecolumnsareaddedtothe.csvfilebetweenthefirstlookup

valueandlookupcolumns.

Here’sanexampleshowingafamilythatusesmultiplelookupvalues.

Making Full Use of the Power of Lookup Tables

Inthiscase,theformulaforfindingthevalueofSocketBottomtoSocketBottomRunreadssomething

likethis:InLookupTableName(referstoparameterunderTextwhereyouenteredthe.csvfilename),

lookforamatchbetweenRevit’sNomi nal Diameter1andNominal

Diameter2parametervaluesand

thelookupvaluecolumnsinasinglerowwithinthelookuptable.IfamatchisfoundRevitwillreturnthe

valuefoundinthatrowforthecolumn“SBtSBR”.Ifnomatchisfound,Revit willreturnavaluee qualto

.03*NominalDiameter1+

1.96*NominalDiameter2+125/256”.

NoticethatNominalDiameter1currentlyhasavalueof2”andNominalDiameter2hasavalueof1

1/4”.Ifwelookatour.csvfile,we’llseeourfirstlookupvalue,calledND1,correspondstoN o minal

Diameter1intheFamilyTypes

dialogandoursecondlookupvalue,calledND2,correspondstoNominal

Diameter2.WhenND1is2”andND2is1.25",SBtSBRis3.0625,or31/16".



Wecandefineasmanyparametersasnecessaryusingthelookuptable,butrememberthatthevalues

aredrivenbythefirstcolumn(s).

Thenumberoflookupvaluesintheformulashouldalwaysbeequalto

thenumberoflookupvaluecolumnsinthe.csvfile.Ifaparameterisunrelatedtothelookupvalue

(typicallythenominaldiam eter),itshouldn’tbepartofthelookuptable.

Here’sanotherlookatinterpretingthis

complexrelationship: 

Making Full Use of the Power of Lookup Tables



It’simportanttounderstandwhatRevitisactuallyco mparingistheparameternameusedinthe

formula(NominalDiameter2),andthecorrespondingcolumn inthelookuptable.Soifyourformula

reads(...,DefaultIfNotFound,LookupValue1,LookupValue2)RevitwilllookatcolumnsBand

C,

respectivelyinthe.csvfile.Ifyourformulaisonlyreferencingasinglelookupvalue,Revi twillneverlook

pastthefirstlookupvaluecolumninthelookuptable.Ifyou’reusing(...,DefaultIfNotFoun d,

LookupValue1)or...,DefaultIfNotFound,LookupValue2) Revitwillalwayscomparethe

parameterin

theformulatoONLYcolumnBinthe.csvfile.Theparameternameinthelookupvaluecolumn(s)isin

nowayusedbyRevit.

LookupTablesImproveWorkflow

Nowthatwe’vecoveredhowlookuptablesareformattedandreferencedwithinRevitfamilies,let’stalk

abouthowtheycanimproveworkflow.Wealreadyknowhowbeneficialtheyaretothepipeand

conduitmodelingprocess,savingusafewsecondswitheachofhundredsofinstancesthroughoutour

project.So

whyaren’tweusingthisconceptwithothercategories?

Lookuptablesmayhaveoriginallybeenintendedtobeuse donlywithPipeFittingsandConduitFittings,

butwecanactuallyuseth em withanycategorywewant!Byusingtheprocessthatwehavediscussed 

forcreatinglookuptablesand

associatingthemwithRevitfamilies,anyfamilythatcanbeflexedinRevit

canbecontrolledbylookuptables.Somearealittlemorelogicalthanothers. Forinstan ce,youcould

addlookuptablestopipevalvefamiliessotheyaresizedtofitthesegmenttheyareplacedin.However,



whencreatingaVAVboxfa mily, ittypicallymakesmoresensetodrivethepara metersthroughformulas

andotherparameterssinceyoudon’twanttheductsizetodictatetheVAVcon nectorsizes.Sohowcan

lookuptableshelpyourworkflow?MaybeinPipeAccessories,orDuctAccessories,orwhy

noteven

Making Full Use of the Power of Lookup Tables

MechanicalEquipment.Getcreative!Ifyoudecidethatlookuptablesaren’trightforthesituationyou

canalwaysconvertthe.csvfiletoatypecatalog(DidImentionthatlookuptablesworkwithfamilies

thathavetypecatalogstoo?).

TrickingtheSystem

Sometimestheparameterwewant

touseforthelookupvaluemaynotbeaSizetypeparameter,even

thoughRevitrequiresthatitbeone fortheformulatoworkproperly.Sowehavetogetcreativewith

ourfamilies.Sinceweknowthatlookuptableswillonlyfunctionwithnumerically‐basedparameter

types,

wecanuseanintermediatepara metertoconverttheinformationwewanttouseintoaformat

thatwillsatisfythelimitati onsoftheworkflow.

Inthisexamplewewanttousealookuptable tosizeapieceofequipmentbasedontheman ufacturer’s

specifications.Toaccomplishthis,wewill

takeallofthepre‐determinedsizesthatwerepopulatedinto

thetypesofthisfamilyandconvertthemintoalookuptable.Doingthis“locksdown”thesesizessothat

theuserwillbeunabletomanipulatethemintheprojectenvironment.

Thelookupvalueforthisfamilywill

bethecapacityofthetank.Wewillusethisvaluebecauseallofthe

othersizeparametersdirectlyrelatetothisfield.However,thisiswherewehitasnag.TheCapacity

parameterisnotaSizeparameter…itisanInteger!Accordingwhatwesaidearlier,weareunable

touse

parametersthatarenotoftheSizetypeasourlookupvalue.



Thisiswherewetrickthesystem.Wecancreateanewparameterthatis ofaSizetypeinorderto

convertthisvaluetosomethingwecanuseinalookuptable.Inthis

case,wemakeaparametercalled

CapacityConverterthatisoftheDuctSizetype.

Making Full Use of the Power of Lookup Tables



Then,backintheFamilyTypesdialog,youcanenterasimpleformulatoconverttheIntegervaluetoa

Sizevalue(ininches).



Oncethisconversionisdonewecanuse thisparameterasthelookupvalueinourlookuptable.The 

resultinglookuptablewould

looksomethinglikethis,whereourlookupvalue“CC”relatestoour

CapacityConverterparameterinRevit.Alloftherema iningcolumnsinthelookupta blewillbelookup

columns.



Making Full Use of the Power of Lookup Tables

TheselookupcolumnscanthenbeusedinRevitviathelookup tableformulawecoveredearlier.For

example,youcanmakethe“H”lookupcolumnrelatetothe“Height”parameterinRevit.

Then,youcancontinuethisprocessfortheremainingparametersinyourfamily.Once

allofthe

parameterscontaintheappropriatelookuptableformula,allthatauserhastodoischangethevaluein

theCapacityparametertooneoftheappropriatecapacityvaluesshowninthetable,andallofthe

dimensionswillautomaticallyupdate.

AStepFurther:AllowingCustomUserInput



Theaboveexampleworksgreatwhenyouwanttocompletely“lockdown”afamily,butwhatifyou

wanttoalsoallowcustomsizesfromtheuser?Wecanaccomplishthisbyaddingsomeaddi tional 

parameterstothefamily.

First,wewillcreateaYes/Noparamete rfortheuserto

specifyiftheywantacustomsize.When

checked,thisparameterwillcompletelyoverridethelookuptable.



Then,wewilladdadditionalparameterstoourfamilyforeveryparameterthatisbeingcontro lledby

thelookuptable.Forexample,theHeight_CustomparameterrelatestotheHeightparameterthatis

being

drivenbythelookuptable.Thecustomparametersaresortedundertheg rouping ofCo nstruction

ratherthanDimensionstogroupthecustomparameterstogetherratherthanbeingmixedinwiththe

lookuptabledrivenparameters.

Making Full Use of the Power of Lookup Tables



Now,weneedtomakeachangetotheformulaforeachoftheparametersbeingcontrolledbythe

lookuptable.WewilldothissothatwhentheusercheckstheCustomcheckmark,thecustomvalues

controlthegeometryratherthanthelookuptablevalues.

IntheexampleoftheHeightparameter,the

formulawilllooksomethinglikethis:



Note:Inthisexample,theDefaultifNotFoundvalueforthelookuptableformulaalsotellsRevitto

usethecustomvalues.



TotranslatethisintoEn glish,iftheCustomparameterischecked,usethevaluefromthecustom

parameter,otherwiseusethesize_lookupformula.



Continuemodifyingtheformulas

fortheremainingparameters.Youshouldnowhaveafam ilythat

allowsforcustominputorforinputbasedonthelookuptable.



Making Full Use of the Power of Lookup Tables

MakingOurOwn

Sonowthatwe’vediscussedtheconceptbehindlookuptables,let’sbuildoneofourown.Forthis

example,we’regoingtobuildasimplepipetransition.

1. OpenthefamilyTransition–A U.rfa. 

2. OpentheFamilyTypesdialog.

3. ClickontheManagebuttonunder LookupTables.

4. Clickthe

Import…buttonandselectPipeFitting–AU.csvfromthelocationitissaved.



5. CreateaFamilyTypeparametercalledLookupTable Name.DefineitasaCommonText

parameterandgroupitunderOther.

6. FortheLookupTableNameparamete r value,enter PipeFitting‐AU.

Nowthat

thelookuptablehasbeenimportedandassociated,wecanreferencethelookuptableto

provideparametervalues.Atthispointyoumightwanttoopenthe.csvfileasareferenceforthe

formulas.

7. IntheFormulacolumnforFittingOD1,enterthefollowing: 

size_lookup(LookupTableName,

"FOD",NominalDiameter1,NominalDiame ter 1) 

Howdidwearriveatthisformula?UsingtheformatfromthefirstpartofthehandoutandPipeFitting‐

CSRW.csv.“FOD”isthenameofthecolumnofvalueswewouldliketopopulatetheFittingOD1

Making Full Use of the Power of Lookup Tables

parameter.ThefirstNominalDiameter1iswhatwewanttouseasavalueifRevitcan’tfindoneinthe

.csvfile.Thelastvalue,thesecondNominalDiameter1isthelookupvalue.ThismeansthatRevitlooks

atthefirstcolumnafterReferenceColumn

(ND)andcomparesittothevalueinthefamilyforNominal

Diameter1.Ifthisvaluecorrespondstoavalueinanyrow,RevitwillpopulatetheFittingOD1

parameterwiththevalueofFODfromthesamerow.

8. RepeattheprocessfortheFittingOD2

parameter,usingtheFODcolumnagain.



9. Saveandclosethefamily.

10. OpenaRevitprojectandloadthenewfamily.

11. Verifythatthefamilyisutilizingthevaluesfromthelookuptableintheproject.

12. Congratulations!Youhavenowsuccessfullycreatedafamilyusingalookuptable.