User's Manual

Introducing the Objet 3-D Printing System
3–4 DOC-07000 Rev. A
Source Files
Objet3‐Dprintingsystemsproducethree‐dimensionalmodelsdesigned
withmost3‐DCADtoolsandwithotherjob‐specific3‐Dapplications.
Objetsystemsaccept:
• STLFiles
• SLCFiles
Objetsystemsfeaturethecapabilityofproducingbothtypesofmodelfiles
simultaneously.
STL Files
STLisshortforStandardTriangulationLanguage.Thislanguageviewsany
objectasacollectionofsurfaces,anddescribeseachsurfaceoftheobjectas
acollectionoftriangles.
Forexample,asquar ecanbedescribedastwotriangles;acube(six
squares)as12triangles.Curvedsurfacesneedmore
trianglestodescribe
them.Thehigherthetolerance(forsmoothsurfaces),themoretrianglesare
needed.Theresultisthathigh‐qualityobjectdescriptionsmeanveryheavy
files.
MostCADsoftwarecanexportSTLfiles.TheObjetsystemutilizesthese
filesforbuildingmodels(rapidprototyping),andalsofordirectlymaking

moldsformass‐producingitems.
STLfilesareASCII(text)files.Thecontentofeachfilebeginswith“solid”
andendswith“end‐solid”(bothlowercase).Betweenthesekeywordsisa
listofthetrianglesthatdescribesthefacesofthesolidmodel.Eachtriangle
definesasinglenormalvector
directedawayfromthesolid’ssurface,
followedbyitsX‐Y‐Zcoordinates.TheseareexpressedasCartesian
coordinatesandarefloating‐pointvalues.Thecoordinatesofalltriangles
shouldbepositiveandshouldfallwithinthevolumeofthemodel.
SLC Files
SLCisshortforStereo‐LithographyContour.SLCfilesdescribetwo‐
dimensionalcontoursofthethree‐dimensionalmodels.Thesecontourlines
arepolylines.
SLCfilesareASCII(text)filesthatsavemodelsasaseriesofslices.This
meansthatmodelsbasedonSLCfilescannotbeorientated;onlytheir
scale
(size)andpositiononthebuildtraycanbecontrolled.Forthisreason,the 
model’sorientationmustbesuitableforproductionbeforeitissavedasan
SLCfile.BecauseofthenatureofSLCfiles,theappearanceofmodelsin
ObjetStudiomaybedifferentthanthesolid‐object
imagesdisplayedfrom
STLfiles.
Printing Materials
Objetprintersproducemodelsbyjettingthinlayersofprintingmaterials
onthebuildtray,untilthecompletemodelisformed.Twotypesofmaterial
areusedinthisprocess:
• Modelmaterial—whichmakesupthefinishedmodel
• Supportmaterial—whichfillsgapsandspacesinthemodelduring
printing,andisremovedafterprinting