Extract Points from Surface/Face

(3D only) Used to graphically and numerically evaluate attributes of a B-spline surface, other than order, poles, and knots, at given locations on the surface. There are four ways to define locations on a surface.

You can access this tool from the following:

Ribbon: Modeling > Surfaces > Surface Utilities > Extract > Points
Toolbox: Surface Utilities

The attributes that can be computed are points, tangents, and normal directions. Computed attributes can be used as reference points or reference lines for other purposes.

Setting	Description
Location(s) Defined By	Sets the manner in which the locations on the surface are defined: Enter Data Point — interactively define a single location on the surface. Parameter — using the U and V Parameter Value settings. The values, which must be in the range 0–1, specify the location from the domain to map to the displayed object. Within MicroStation, the domain is from 0.0 to 1.0. (%) Dist[ance] Along Curve — using the Dist From U and V Start(%) settings. The values are each a percentage of the total length of the curve in the u or v direction on the surface. For example, to extract the tangent direction of a surface at its middle point, set both Dist. From U and V Start(%) to 50. Point Array — using the Number of U and V Points settings. The values are the number of evenly spaced locations on the curves in the u and v direction, respectively. For example, to evaluate at 200 evenly spaced locations on the surface, set Number of U Points to 10 and Number of V Points to 20.
Tangent Plot Scale	Sets the scale factor applied to the magnitude display. If set to 1.0, the computed tangents will be the true derivative vector — that is, the tangent direction with the magnitude.
Normal Plot Scale	Sets the scale factor applied to the perpendicular line segments in Normal output. If set to 1.0, the true normal vector is displayed — that is, the direction plus its true magnitude.
U/V Parameter Value	Sets the parameter values applicable to the Parameter option for defining locations on the surface; see Location(s) Defined By above.
Dist[ance] From U/V Start(%)	Sets the distance values applicable to the Dist. Along Curve option for defining locations on the surface; see Location(s) Defined By above.
Number of U/V Points	Sets the numeric values applicable to the Point Array option for defining locations on the surface; see Location(s) Defined By above.
[Compute] Points	If on, the points on the surface at which evaluation is performed are displayed in the output.
[Compute] Tangents	If on, the surface's tangents are computed. In the context of this tool's operation, a tangent is computed as the partial derivatives of the surface in both parametric u and v directions.
[Compute] Normal	If on, the surface's normal directions are computed.

Key-in: EVALUATE FACE

Note: This tool can also be used to evaluate 3D primitive surfaces.