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ParametricDesignwithOpenSCAD
JaySummet [email protected]
Copyright Jay Summet All Rights Reserved
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OpenSCAD
OpenSourceparametricdesigntool ExecutablesforWindows,Mac,Linux
Freetodistribute,freetouse,crossplatform
Convertstextualinstructionsinto3Dshapes
SupportsConstructiveSolidGeometry(CSG)
modeling
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ResourceLinks
Downloads:http://www.openscad.org
UserManual:http://en.wikibooks.org/wiki/OpenSCAD_User_Manual
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Comments
C/Java/C++commentingconventions
Anytextafteradoubleforwardslash(//)onaline
isignoredbytheparser.
Multilinecommentsarestartedwithaslashstar
(/*)andendedwithastarslash(*/)
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NamedValues
a.k.a.Variables Anameisassignedavaluewiththeassignment
operator(=).Canuseexpressionsontherighthandsideoftheassignmentoperatortocalculatevalues.
CAUTION!:NamedValuesaresetatcompiletime,NOTRUNTIME!Lastassignmenttakesprecidence!(Butseetheassignstatement...)
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Example:
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VariableAdvice
Tokeepyourselfsane: Alwaysmakenewvariables,neverreassignnew
valuestooldvariables.
Thinkofvariablesasconstantsordescriptive
namesinsteadofvariables.
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Vectors
Example:dims=[w,d,h];
Usingsquarebrackets,declareavectorofvalues,
eitherfromconstants,expressions,ornamedvalues/variables.
Example:dims=[w*2,d+3,17];
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Statements
REQUIREsemicolonstoend!
Ifyouforgetthesemicolontheparserwilltypically
displaytheerrorasoccuringatthebeginningofthenextline.
Socheckthelinebeforetheerror!
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Sphere
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Transformations
Objectsandentiresubtreescanhavetransformationsappliedtothemthataffecttheirsize,placement,colorandshape.
Mostcommonlyused:rotate,translate
Alsouseful:mirror,scale,color,hull
Advanced:multmatrix,minkowski
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SphereTranslated
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subtree
Thetranslatecommandworksonasubtreethatcontainschildnodes.Bydefault,thesubtreeincludestheimmediatelyfollowingobject,endedbyasemicolon.
Ifyouuse{curlybrackets}todeliniatesubtrees,youcanincludemorethanonemoduleorchildnode.
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Sphere&CubeTranslated
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SphereNotTranslated
Note the extra semicolon!
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CenteringonOrigin
Bydefault,whenasphereiscreateditiscenteredontheorigin.
However,acubeiscreatedwithitscornerattheoriginbydefault.
Thisiswhythecubeinthepreviousslideisnotcenteredwithinthesphereaftertheyarebothtranslatedthesameamount.
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Sphere&CubeTranslated
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Creatingacenteredcube
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SpecialArcControlvariables
$fnNormallysettozero(0)toallow$faand$fstotakeeffect.Ifsettoanumber,allcirclesaremadewithexactly$fnstraightlinefragments.
$faMinimumangleforafragment.Numberoffragments=360/$fa.Defaultsto12(i.e.30fragmentsforafullcircle)
$fsMinimumfragmentsize.Defaultsto2.Verysmallcircleswillhaveasmallernumberoffragmentsthan$faspecifies.
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Justuse$fn
$fnistheeasiesttouseIfyouwantcircles,cylinders,andspherestobesmoother,increase$fn.
Thelarger$fnis,thelongercalculationstakeandthemorevertices/filesizeyourexportedmodelswillhave.
Cansetglobally,orpasstospecificshapesindividually.
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$fnexample
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Modules
Likefunctions,butcanaffectsubtreesthatfollowthem,socanbeusedtoimplementcomplextransformationsaswellasobjects.
Allowyoutoreusecode. Canacceptparameters.
Useacurlybracketstodeliniatethesubtreeof
codethatisthemodule. Havelocalvariablenames.
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VariableScope
root/globalscopeisdifferentfromwithinamodule,soyoucanredefineavariablewithinamodulewithoutaffectingitsvalueoutsideofthemodule.
Reminder:Becausevariablesaresetatcompiletimeinsteadofruntime,youcannotreassignavariableinsideofanifsubtree.
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HexNutModule
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Justuse$fn
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MakeSpheres
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MakeSpheres
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MakeSpheres
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MakeSpheres
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Iterationviaforloops
for(variable=)variableisassignedtoeachiteminthevectorandthesubtreeisexecuted.
for(variable=) Range=[:] Range=[::]
Note:Rangesyntaxusescolons,andtheresulting
rangeincludesthestartandendpoints
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forRange
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forVector
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for(multiplevariables)rangeandvector
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ifstatements
Syntaxlooksabouthowyouwouldexpect.
Conditionallyexecutedsubtreebasedupon
booleanexpressionwithoptionalelseclause.
Comeinusefulifyouwanttohave
twodifferentversionsoftheobject(differentboltpatterns,adapterplates,etc..)
Differentstyles/shapesbaseduponuserparameters.
debugvsregularmode.
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ifsyntaxif ( ){ } else { }
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ifexample
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ifexample
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ConstructiveSolidGeometry(CSG)
Consistsofmodelingcomplexpartsasunions,intersections,anddifferencesof(relatively)simplerparts.
Thehullandminkowskitransformationsarealsousefulforcreatingcompoundobjects.
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Makingahollowbox
Makealargecubeforyouroutsidedimensions.
Makeasmallercubeforyourinsidedimensions.
Translatethesmallercubeinsidethelargercube
(andhaveitstickoutthetopbyaverysmallamountsuchas0.01)
Ithastopokeoutofthetopjustalittlebitsothatthetopfaceisdefinatelyopen!
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TwoCubes
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HollowBox
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HalfSphereintersection
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Morethanonewaytoskinacat
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OrderMatersforDifference!
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hull
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Modifiercharacters
Characters(#,!,%,*)prependedtoobjectstomodifyhowtheyareprocessed.
Generallyusedtovisualizewhatishappening,tryoutalimitedsetofcodewithoutothercodeinterfearing,etc.
Mostusefulisthe#orDebugModifier,thatdrawsobjectsintransparentpinkforvisualizationpurposes.
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intersectionDebugView
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OtherModifierCharacters
Theothermodifiercharactersactuallyaffecthowyouroutputisgenerated.
%backgroundmodifierdrawsthesubtree/objectwithtransparentgray,butignoresitforallotherrenderingpurposes.
!rootmodifierIgnoreeverythingELSEinyourfile,andonlyrenderthissubtree!
*disablemodifierDisable/ignorethissubtree.
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ResourceLinks
Downloads:http://www.openscad.org
UserManual:http://en.wikibooks.org/wiki/OpenSCAD_User_Manual
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