1. Single References.Kiu la chn ny cho php ta to mt im m v tr ca
im nm trn mt i tng no . Hay trong hp thoi DATUM POINT References ch
xut hin mt i tng references l Surface, Edge, Circular Edge,
Vertex.Trnh t to points vi la chn Single References:Click hay theo
ng dn Insert > Model Datum > Point. Hp thoi DATUM POINT xut
hin. Ta c cc hnh thc xc nh v tr ca point nh sau:
a). Point nm trn mt mt Surface:Trnh t thc hin nh sau: Insert
> Model Datum > Point > Hp thoi DATUM POINT xut hin. Click
chn v tr ca point trn mc surface mun to, lc ny trong hp thoi DATUM
POINT c cc la chn nh sau:
Ta s thc hin vic to mt Datum Point trn mt chi tit nh di:
Khi chn On th im to s nm ngay trn mc m ta chn lm References, khi
chn Offset s cho php chng ta offset point ny theo phng vung gc vi
mc References mt khong ta nhp.
b). Point nm trn mt cnh (Edge):Trnh t thc hin nh sau: Insert
> Model Datum > Point > Hp thoi DATUM POINT xut hin. Click
chn cnh mun c point, lc ny hp thoi DATUM POINT s c cc la chn nh
sau:
Mun to nhiu point nm trn mt cnh v c cng im End Of Curve th:
Right click ln point va to (PNT0) > Duplicate.
c). Point nm trn mt cung trn (Circular Edge):Cch to cng tng t nh
to point nm trn mt cnh (Edge) nu Point nm trn cnh ca cung. Trong
trng hp point nm ti tm ca cung c chn th ta s la chn trong hp thoi
DATUM POINT thng s Center.
d). Click chn trc tip vo im Vertex:
2. Multiple References.Ngc li vi Single References, point c to
ra bng cch ly giao nhau gia cc i tng references. Trong hp thoai
DATUM POINT References s xut hin nhiu i tng references.
a). To point l giao gia 3 mt phng (Three Plane):Trnh t thc hin
nh sau: Insert > Model Datum > Point > Hp thoi DATUM POINT
xut hin. Click chn 3 mc phng giao nhau to Point:
Trong hp thoi DATUM POINT References s xut hin 3 references nh
hp thoi bn di:
b). To point l giao gia 2 cnh (Edge):Click chn hai cnh giao
nhau:
c). To Point l giao gia mt Datum Axis v mt Datum Plane:
3. Sketcher Points.Cho php chng ta to cc point ngay trong mi
trng Sketch. C cc hnh thc to mt point trong mi trng sketch sau.Trnh
t thc hin lnh: Click Insert > Model Datum > Point >
Sketched. Hay trn thanh cng c Datums toolbar, click mi tn m thanh
cng c Datum Point Palette , v click , hp thoi Sketch Datum Point
xut hin. Chn mt mt phng vo trong mi trng Sketch > Click Sketch
trn hp thoi Sketch Datum Point vo mi trng v sketch. Trong mi trng
sketch hnh thnh 1 point ta c hai cch nh sau: Click to point. Trong
trng hp nu c s giao nhau gia 3 ng Contruction Curve tr ln th cng to
nn point, v d bn di l s giao nhau gia 3 ng contruction curve:
4. Offset Cordinate System.Cho php ta to cc im c offset t gc ta
theo cc phng X, Y, Z.a). Trnh t thc hin lnh nh sau: Click Insert
> Model Datum > Point > Offset Cordinate System. Hay trn
thanh cng c Datums toolbar, click mi tn m thanh cng c Datum Point
Palette , v click , hp thoi Offset CSys Datum Point xut hin.
Ta s nhp mt s ta ca 6 point, v d nh trong hp thoi Offset CSys
Datum Point bn di:
ImportCho php chng ta ly mt file c dng (*.pts), file ny c to trc
bng lnh to point Offset Cordinate System. SaveCho php chng ta la li
cc point ang to di dng mt file c ui l (*.pts). Update ValuesCp nht
gi tr thay i ca cc point.
b). Khi hiu chnh nhanh gi tr ca cc point th: Right click ln
point hiu chnh > Edit. Lc ny xut hin hp thoi MOD ARR NUM thng
bo:
SingleCh hiu chnh 1 point, im ny chnh l im m ta chn vo v right
click hiu chnh. AllHiu chnh tt c cc point. Lc ny trn mn hnh s xut
hin:
c). i vi h ta tr (Cylindrical)S cho php chng ta nhp cc thng s v:
bn knh (Radius). Gc xoay (Angle). V tr theo phng Z.Trong gc xoay
(Angle) c tnh t chiu dng trc X ca gc ta v xoay ngc chiu kim ng
h.
d). i vi h ta cu (Spherical)Cho php chng ta nhp cc gi tr gm: Bn
knh Radius v 2 gc. Bn knh c xc nh theo phng Z, gc u tin c tnh trong
mc phng X-Y ca gc ta v c tnh ngc chiu kim ng h theo chiu dng ca trc
X, gc cn li c tnh ngc chiu kim ng h theo chiu dng ca trc Z.
5. Field Datum Point.Cho php chng ta to ra cc point m khng yu cu
kch thc, la chn ny thng c s dng to cc point trong mi trng thit k
khng i hi kch thc chnh xc.Trnh t thc hin lnh nh sau: Click Insert
> Model Datum > Point > Field. Hay trn thanh cng c Datums
toolbar, click mi tn m thanh cng c Datum Point Palette , v click ,
hp thoi Field Datum Point xut hin:
Chn mt references lm v tr t point nh l mt Curve, Edge, Surface,
Quilt. Click Ok trn hp thoi Field Datum Point kt thc lnh.