Special Characters |
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| 2D-Curve | A 2D-Curve is defined in the u-v-Parameterspace of the surface. A 2D-Curve yields information of the surface, for example the curvature of the surface. A 2-D Curve does not follow the modification of the surface. If you modify the surface there will be a gap between the 2-D Curve and the surface. | |
| 3D compass | The 3D compass is a three-axis system used to define the plane into which any action is performed. It is displayed whenever you are creating an element or applying modifications to this element. | |
| 3D-Curve | Normally a curve is a 3D-Curve. A 3D-Curve placed on a surface does not yield any information about the surface. | |
A |
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| approximation | A surface or a curve is converted into a NUPBS surface or a NUPBS curve. | |
| attenuation | Factor to attenuate the speed with of the mouse displacement. | |
B |
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| basic surface | If a surface is trimmed at an
arbitrary curve, it is sometimes wanted that the trimmed surface yields the
information about the input surface. This input surface is called Basic
Surface (if it is not trimmed). A trimmed surface is called a face and the underlying untrimmed surface is called the Basic surface. |
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| blend curve | A curve created to connect two pre-existing curves. | |
| blend surface | A surface created to connect two pre-existing surfaces | |
C |
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| chain of curves | A chain of curves contains at least one curve. If there are more than one curve, the endpoint of the first curve has to meet the start point of the second curve and so on. Gaps and overlapping are not allowed. | |
| cloud of points | A set of points in space. A cloud of points may consist of a single point or several million points. | |
F |
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| face | A face is a trimmed surface. A face has an underlying Basic Surface. | |
| feature modeling | Some Commands, e.g. Fillet, have the Option Feature Modeling. The term Feature Modeling is explained with the Command ACA Fillet. | |
G |
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| G0 | If the endpoint of curve K1 meets the endpoint
of curve K2 then we say: At this point both curves are connected with order
of continuity 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. |
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| G1 | The curve K1 and the curve K2 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. |
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| G2 | The curve K1 and the curve K2 are connected
with the order of continuity G1 in the point P. We look at the curvature
vector of K1 in point P and the curvature vector of K2 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 K. 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. K1 may have the radius R and K2 may have the radius r at the common point, with r<R, then yields:
The maximum of this error is 2. Sometimes this error is measured in percent % then its maximum is 200%. |
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| G3 | The curve K1 and the curve K2 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. |
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| Gaussian curvature | The Gaussian curvature K of a surface at a
point is calculated as follows: K = 1 Where R1 and R2 are the principal curvature radii at the point. |
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| global deformation | A deformation that is applied globally to a set of elements, as opposed to a deformation successively applied to different elements. | |
I |
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| inflection line | Curve, lying on a surface, which curvature value is 0 at each point. | |
| isophote | A line or surface on a chart forming the locus of points of equal illumination or light intensity from a given source. | |
M |
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| match curve | A curve deformed so as to connect another curve, while taking the continuity type into account. | |
| match surface | A surface deformed so as to connect another surface, while taking the continuity type into account. | |
| mesh line | A line on a surface used to deform this surface according to various laws, and types of deformation. | |
N |
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| NUPBS | A NUBS, Non Uniform B-Spline is also called NUPBS, to make it more clear that it is a polynomial curve and not a rational curve. See NURBS. | |
| NURBS | A NURBS, Non Uniform Rational B-Spline, is a NUBS with a rational component. Rational means that the weight of the Control Points must not have the value 1. With a Rational Curve a Circle and a Hyperbola can be described exact. | |
R |
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| reflection line | A curve visualized on a surface, that reflects the light emanating from a grid of neon located above the surface. | |
S |
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| surface | In CATIA, surfaces are
parameterized with the u- and v-Parameters running from 0 to 1. A surface has an order in u- and an order in v-Direction, 2<=order<=16. The simplest surface is a 4-Point-Patch of order 2 in u-Direction and order 2 in v-Direction. A surface can have only one patch or several patches. The command Geometric Information shows you in the panel Geometric Analysis the available information. A surface can be trimmed for example by the command Breaking Surfaces. It can be untrimmed by the command Untrim. A trimmed surface is called Face and contains all the information of the untrimmed surface. Because of this a command can work on the Face or on the (untrimmed) Basic Surface. |
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T |
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| topological | Concerned with relations between objects abstracted from exact quantitative measurements. | |
| topological operation | An operation retaining the topological properties of the element undergoing the specified transformation. | |
| trimmed surface | See Surface. | |
U |
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| untrimmed surface | See Surface. | |