catia的online中关于G0,G1,G2,G3的部分，可惜没有图示：
G0 If the endpoint of curve C1 meets the endpoint of curve C2 then we say the order of continuity of both curves is (in this point) G0.
If one edge of surface S1 meets an edge of the surface S2 then we say along this edge both surfaces are connected with the order of continuity G0.
If the G0-continuity is missed then we have a so called G0-error. This error is an absolute error, a distance, and it is measured in mm or inches.
G1 The curve C1 and the curve C2 are connected with the order of continuity G0 in the point P. If both curves in the point P run into the same direction, this means the angle between the tangents of both curves is 0, then we say the order of continuity is G1.
The surface S1 and the surface S2 are connected with the order of continuity G0 along the curve C. We take the normal of S1 in a point near the curve C and run with this normal over the border to S2. If the normal does not change its angle from one point of the border of S1 to the nearest point of S2 then we say the order of continuity is G1.
If the G1-continuity is missed then we have a so called G1-error. This error is an absolute error, an angle, and it is measured in deg of rad.
G2 The curve C1 and the curve C2 are connected with the order of continuity G1 in the point P. We look at the curvature vector of C1 in point P and the curvature vector of C2 in point P. If both vectors have the same direction and the same absolute value, then we say the order of continuity is G2.
The surface S1 and the surface S2 are connected with the order of continuity G1 along the curve C. If each curve on S1 which runs over the border to S2 can be continued with another curve on S2 and their order of continuity is G2 then we say both surfaces are connected with the order of continuity G2.
If the G2-continuity is missed then we have a so called G2-error. This error is a relative error and it is calculated with the following formula. C1 may have the radius R and C2 may have the radius r at the common point, with r<R, then yields: error= 2*(R-r)/(R+r)
The maximum of this error is 2. Sometimes this error is measured in percent % then its maximum is 200%.
G3 The curve C1 and the curve C2 are connected with the order of continuity G2 in the point P. For the definition of the G3-continuity we look at the curvature hedgehog, as it can be created with the command Porcupine Curvature Analysis. We look at the envelope of the curvature hedgehog. If this envelope has at the desired point G1-continuity then we say the order of continuity between both curves is G3.
If the G3-continuity between both curves is missed, the G1-continuity of the envelope is missed, then we have a so called G3-error between both curves. This error is an absolute error, an angle, and it is measured in deg of rad and it is the G1-error of the envelope. G3-continuity between surfaces is defined on the curves between both surfaces on the same way. |
发表于 2003-6-7 13:21:08
发表于 2003-7-10 19:41:19
