「インタラクション，97」 平成9年2月

Tool−Based3DHapticInterfacefbrDirectandInteractiv早SurfaceModelling
JuliYamashitaandYukioFukui

NationalInstituteofBioscienceandHuman−Technology
l−1，Higashi，Tsukuba，maraki305，Japan −E−mail：juli＠nibh■gO・JP，fukui＠nibh・gO・JP
Three dimensionalfbrm manlPulation requlreS

Currently，Onlytriangularsurfaceiscuttable・

intuitive，interactive，and easy to use 3D man−【Result】

machineinterface，Which has been difficult withexistlng 2Dinput／output devices such as CRTFirstly，1tisverylntuitive；JuStPuShwhereyouwantto

The direct manlPulatinginterfaceis remarkable．

displays and mice．Recent VirtualReality（VR） defbrm，thenyoucanmanlpulatesurfaceitself，nOta
technology finally provides truly3DI／O devices
handlenorvertices．DeformationofB−Splinesurface

use魚旦Ifbrinteractive3D Computer Aided Design makesitsadvantageclearer；yOu donot have to be（CAD）interface．

awareofcontroIpoints，butjustpushwhereyouwant

Thispaperpresentsavirtualsurfacemodelerbased

todefbrm．Secondly，theinterfaceisindependent ofform representations・Both B−Spline and triangularon tool−based direct 3D interface with fbrce

ftedback．Withaforcefeedbackdevice and newly
developeddirect shape manlPulation algorithms，it
allowsauserto touch，一…ftel， anddefbrmsurfaces

SurfacearemanlPu）atedinexactlythesamemanner，‖pushanddefbrm・一一Thirdly，forcefeedbackplaysan

importantrole，eSpeCiallyincuttingoperation，tOkeep

directlywithviftual 一tooIs‖in3Dspace・【SystemConfiguration］

tool stlPOnthesurface・Thesystemconsistsofagraphicworkstation（SGIIndigo2）and a PHANToM force fbedback device

ThesystemhasmanyproblemstobesoIved：（l）Finerdeveloped at MIT（6 DOFinput with optional

Whenatooliscaughtinanarrowcomer，undesirable【FutureWork］

COntrOlalgorithms for force fbedbackare needed・

gimbal，3DOFfbrceoutput）［1】orafbrceftedback oscillation occurs．（2）Self crossing avoidance ofdeviceof6DOF，OurOriginaldevelopment【2］呼ig・
surfhcemightbeneeded．（3）Surfacematerialshould1）．Aforceftedbackdeviceworksasa3Dcursorandaffbctftedbackfbrce，SuChasfrictionandsoftness．（4）Forceshouldalsobedifftrentaccordingto the tool
a3Dhapticdisplay・Theworkstationandadevice
corrmunicate ovef EtherNet；the device sendsit s beingused．（5）TooIs and underlyingfreeformed
POSitionandrotationdata（6DOFdata）to［thework− surfhce representations fbr topology changeable
Station，Which keeps a11geometric data・Itdetects defbrmation，SuCh as，Cutting and glueing・（6）collisionbetweensurfaceo句ectsandthe3Dcursor， Experi叩ent Of usability evaluationis needed・（7）or，a‖tool，■一andretums theshapeftaturedataofthe Development of networked co−Operative CAD
co11isionpoint・FeedbackforceisthencalculatedbyenvlrOnment．
thedevicecontro11er（PC）basedontheshapeftaturesRe托rences【3］．Theworkstationindependently renders surface【l】Massie，T．Hニー：‖InitialHaptic Explorationswith thePhan10m：VirtualTouch Through PointInteraction，●O句ectsgraphically・【VirtualTooIs】

Severalvirtualdirect sculptlng tOOIs have been

Master，sthesisatM．Ⅰ．T．，1996．

【2］Yokoi，H．，J．Yamashita，Y・Fukui，andM・，Shimqjo：

implemented：CurVlngtOOl，tWistlngtOOl・andcutter ‖DevelopmentoftheVirtualShapeManipulating．System：ftool（Fig．2−4）．UsageoftooIsisstraightforward；a Proc．ofICAT 94，1994．
userpushesasurfacewithatool・thenthe surfacewillbedefbrmedormanlPulated as being pushed，

with ‖Loosely Coupled一．Force Feedback Device：accordingtothetool［4，5】・Atthesametime，the PHANToMUser sGroupWorkshop96，1996・

user ftels fbrce ftedbackfrom the device，Which【4］Yamashita，J．and Y．Fukui：一 A Direct Defbrmation

increasestherealityofformmanlPulationverymuch・Method，．．Proc．ofIEEEVRAIS 93，1993．
【5］Yamashita，J．etal：
3D−DDM：ATYIreeDimensional−
Underlying geometry of the modeleris B−Spline
surface（degree3，aSheetofpatchcanbehandledat DirectManipulationMethodofB−SplineSu血ces・‖Trans・ofIEEJapan，Vol．115−C，No・2，1995・（inJapanese）

onetime）andtriangularpolygonalsurface・−45−

GraDhicWorkstatiQn

且臣￡￡￡鮎！旦蔓と萱n＿辿委追由鹿ObjectGeometryData＆Mode蔓er
PHAN7bM

Nominalpositionresolution：0．01mm

Workspace：35x35x20cm

Nomina‡positionreso［ution：0．07mm

Max・eXertableforce（HorizontaI）：700N（71kg）
Max・eXertabIeforce（Vbrtical）：300N（31kg）
Conto＝edlnertia：〜100g
Controいate：〜100日z

Workspace：8x17x25cm
Max，eXertableforce：8．5N（0．9kg）

ElherNet‡ne輔a：く100g

ControIrate：〜KHz

Fig．1ViSurfSystemConfiguration Thesystemhas2forcefeedbackdeviceswhichasynchronously
COmmunicatewjthagraphicwokstationovertheEtherNet（dottedIineswitharrows）．Hapticrendering
OneaChPCisdonebasedonshapefeaturessentbythemode［erontheworkstation．

Figure2．Deformation

WithcurvIngt0Ol；LEFT：
PO［ygona］surface，
RIGHT：B・SpIinesurface

ApIane（1）pushedbya
PenC‖Iiketooloracursor
isdeformedasbeing
PuShed，（（2）and（3））A

us即doesno＝ouch叩OIPOintsnorvertic由，butthe
SuげaceitseIf．PoIygonal

Surfaceonthele代uses
PHANlbMdeviceand
B・Sp＝nesuHace（d6gree3）
Ontheri9htisdeformed
WithourInPutdevicewith
forcefeedback，Whichis
ShowninthelowerrightCOrnerOfe由Chsnapshot．

Figure3．TbistingTbo］
Bothtriangu暮arsurface（LEFT）andB・Splinesurface（RIGHT）canbe

twistedinthesameway；PuShthe
SuHacetwistingthehandleofthe
device．

Figure4．CutterTboI

Ap（aneiscutwithacuttertooLTbpo‡ogyofthe
Surfacehasbeenchanged．
−46−