Package Documentation

Object: face (The :surf Package)
Mixins: surface

Description

This object represents a (possibly) trimmed surface contained within a brep. It answers all the local messages of face, and it has surface mixed in as well, so it will answer all the surface messages. Note however that the local surface messages will operate on the basis, not on the trimmed representation. The messages for face will operate on the trimmed representation. This object is not meant for direct instantiation; rather, a brep will contain a quantified set of faces (called "faces"), and trimmed surface also mixes in face, so a trimmed-surface will answer all the face messages.


Input Slots (required)

brep gdl brep object

This is the brep object which contains this face object.



Input Slots (optional)

basis-surface gdl nurbs surface

The underlying surface, before any trimming takes place.


brep-tolerance [from surface] number

Overall tolerance for the internal brep representation of this surface. Defaults to nil. Note that a value of nil indicates for SMLib a value of 1.0e-05 of the longest diagonal length of the brep.


built-from [from surface] gdl surface

Specify this if you want this surface to be a clone of an existing surface (note - this uses a shared underlying surface object, it does not make a copy)


color-decimal [from geometry-kernel-object-mixin] vector of three real numbers

The RGB color of this object as imported from an external format (e.g. IGES) or as specified in :display-controls. Defaults to the foreground color specified in *colors-default*. This message should not normally be overridden in user application code.


end-caps-on-brep? [from surface] boolean

Indicates whether to attempt automatic endcaps on conversion of this surface to a brep. Note that this might change in future to a keyword value for :min, :max, or :both to provide more control.


hidden? [from vanilla-mixin*] boolean

Indicates whether the object should effectively be a hidden-object even if specified in :objects. Default is nil.


iges-level [from geometry-kernel-object-mixin] integer

Synonym for the layer.


image-file [from base-object] pathname or string

Points to a pre-existing image file to be displayed instead of actual geometry for this object. Defaults to nil


layer [from geometry-kernel-object-mixin] integer

The primary IGES-compatible level (layer) on which this object resides. Defaults to the first of the levels. This slot can be overridden in user code to specify a new layer which will be written out when this object is exported with the IGES output-format.


levels [from geometry-kernel-object-mixin] list of integers

The IGES-compatible levels (layers) on which this object resides. GDL does not currently support writing out multiple levels (layers) through the IGES writer ; only the first of these will be output if the object is exported with the IGES output-format (please contact Genworks if you need all levels (layers) to be written out).


obliqueness [from base-object] 3x3 orthonormal matrix of double-float numbers

This is synonymous with the orientation.


onclick-function [from base-object] lambda function of zero arguments, or nil

If non-nil, this function gets invoked when the user clicks the object in graphics front-ends which may or may not support this functionality (see viewport-html-div).


rational? [from surface] boolean

Returns non-nil iff this surface is rational, i.e. all weights are not 1.


root [from vanilla-mixin*] gdl instance

The root-level node in this object's ``tree'' (instance hierarchy).


safe-children [from vanilla-mixin*] list of gdl instances

All objects from the :objects specification, including elements of sequences as flat lists. Any children which throw errors come back as a plist with error information


sew-and-orient-brep? [from surface] boolean

Indicates whether brep representation should undergo a sew-and-orient operation. Defaults to nil.


strings-for-display [from vanilla-mixin*] string or list of strings

Determines how the name of objects of this type will be printed in most places. This defaults to the name-for-display (generally the part's name as specified in its parent), followed by an index number if the part is an element of a sequence.


tessellation-parameters [from surface] plist of keyword symbols and numbers

This controls tessellation for the brep of this surface. The keys are as follows:

  • :min-number-of-segments
  • :max-3d-edge-factor
  • :min-parametric-ratio
  • :max-chord-height
  • :max-angle-degrees
  • :min-3d-edge
  • :min-edge-ratio-uv
  • :max-aspect-ratio
and the defaults come from the following parameters:
   (list 
       :min-number-of-segments *tess-min-number-of-segments*
       :max-3d-edge-factor *tess-max-3d-edge-factor*
       :min-parametric-ratio *tess-min-parametric-ratio*
       :max-chord-height *tess-max-chord-height*
       :max-angle-degrees *tess-max-angle-degrees*
       :min-3d-edge *tess-min-3d-edge*
       :min-edge-ratio-uv *tess-min-edge-ratio-uv*
       :max-aspect-ratio *tess-max-aspect-ratio*)


tolerance [from surface] number

Approximation tolerance for display purposes.


visible-children [from vanilla-mixin*] list of gdl instances

Additional objects to display in Tatu tree. Typically this would be a subset of hidden-children. Defaults to NIL.



Input Slots (optional, defaulting)

center [from base-object] 3d point

Indicates in global coordinates where the center of the reference box of this object should be located.


display-controls [from base-object] plist

May contain keywords and values indicating display characteristics for this object. The following keywords are recognized currently:

:color
color keyword from the *color-table* parameter, or an HTML-style hexidecimal RGB string value, e.g. "#FFFFFF" for pure white. Defaults to :black.
:line-thickness
an integer, defaulting to 1, indicating relative line thickness for wireframe representations of this object.
:dash-pattern
(currently PDF/PNG/JPEG only). This is a list of two or three numbers which indicate the length, in pixels, of the dashes and blank spaces in a dashed line. The optional third number indicates how far into the line or curve to start the dash pattern.


isos [from surface] plist with keys :n-u and :n-v

The number of isoparametric curves to be displayed in each direction. This value comes from the value of :isos on the display-controls if that exists, and defaults to *isos-default* otherwise.


orientation [from base-object] 3x3 matrix of double-float numbers

Indicates the absolute Rotation Matrix used to create the coordinate system of this object. This matrix is given in absolute terms (i.e. with respect to the root's orientation), and is generally created with the alignment function. It should be an orthonormal matrix, meaning each row is a vector with a magnitude of one (1.0).



Computed Slots

bounding-box [from base-object] list of two 3d points

The left front bottom and right rear top corners, in global coordinates, of the rectangular volume bounding the tree of geometric objects rooted at this object.


u-iso-curves [from surface] sequence of curve objects

The isoparametric curves in the U direction.


v-iso-curves [from surface] sequence of curve objects

The isoparametric curves in the V direction.



Hidden Objects (sequence)

edges sequence of gdl edge objects

The Edges contained within this brep.



GDL Functions

area number

Returns the area of the face.

keyword arguments:
desired-accuracy Number, Default Value: 1.0e-6
Desired accuracy of result. Should not be smaller than 0.00000001 (10e-08)
face-thickness Number, Default Value: 0.0
Optional thickness

area-moments-of-inertia 3d vector (ie 3d point)

Returns the Area Moments of Inertia of the face.

keyword arguments:
desired-accuracy Number, Default Value: 1.0e-6
Desired accuracy of result. Should not be smaller than 0.00000001 (10e-08)
face-thickness Number, Default Value: 0.0
Optional thickness

area-products-of-inertia 3d vector (ie 3d point)

Returns the Area Products of Inertia of the face.

keyword arguments:
desired-accuracy Number, Default Value: 1.0e-6
Desired accuracy of result. Should not be smaller than 0.00000001 (10e-08)
face-thickness Number, Default Value: 0.0
Optional thickness

area-second-moment-about-coordinate-axii 3d vector (ie 3d point)

Returns the Area Second Moment About Coordinate Axii of the face.

keyword arguments:
desired-accuracy Number, Default Value: 1.0e-6
Desired accuracy of result. Should not be smaller than 0.00000001 (10e-08)
face-thickness Number, Default Value: 0.0
Optional thickness

area-static-moments 3d vector (ie 3d point)

Returns the Area Static Moments of the face.

keyword arguments:
desired-accuracy Number, Default Value: 1.0e-6
Desired accuracy of result. Should not be smaller than 0.00000001 (10e-08)
face-thickness Number, Default Value: 0.0
Optional thickness

moments plist

Returns the moments of the face. The plist contains keys: :area-static-moments, :area-moments-of-inertia, :area-products-of-inertia, :area-second-moment-about-coordinate-axii, :volume-static-moments, :volume-moments-of-inertia, :volume-products-of-inertia, and :volume-second-moment-about-coordinate-axii.

keyword arguments:
desired-accuracy Number, Default Value: 1.0e-6
Desired accuracy of result. Should not be smaller than 0.00000001 (10e-08)
face-thickness Number, Default Value: 0.0
Optional thickness

precise-properties multiple values: number, number, and plist

Returns the area, volume, and moments of the face. The moments are labeled as: :area-static-moments, :area-moments-of-inertia, :area-products-of-inertia, :area-second-moment-about-coordinate-axii, :volume-static-moments, :volume-moments-of-inertia, :volume-products-of-inertia, and :volume-second-moment-about-coordinate-axii.

keyword arguments:
desired-accuracy Number, Default Value: 1.0e-6
Desired accuracy of result. Should not be smaller than 0.00000001 (10e-08)
face-thickness Number, Default Value: 0.0
Optional thickness of the trimmed surface

volume number

Returns the volume of the face.

keyword arguments:
desired-accuracy Number, Default Value: 1.0e-6
Desired accuracy of result. Should not be smaller than 0.00000001 (10e-08)
face-thickness Number, Default Value: 0.0
Optional thickness

volume-moments-of-inertia 3d vector (ie 3d point)

Returns the Volume Moments of Inertia of the face.

keyword arguments:
desired-accuracy Number, Default Value: 1.0e-6
Desired accuracy of result. Should not be smaller than 0.00000001 (10e-08)
face-thickness Number, Default Value: 0.0
Optional thickness

volume-products-of-inertia 3d vector (ie 3d point)

Returns the Volume Products of Inertia of the face.

keyword arguments:
desired-accuracy Number, Default Value: 1.0e-6
Desired accuracy of result. Should not be smaller than 0.00000001 (10e-08)
face-thickness Number, Default Value: 0.0
Optional thickness

volume-second-moment-about-coordinate-axii 3d vector (ie 3d point)

Returns the Volume Second Moment about Coordinate Axii of the face.

keyword arguments:
desired-accuracy Number, Default Value: 1.0e-6
Desired accuracy of result. Should not be smaller than 0.00000001 (10e-08)
face-thickness Number, Default Value: 0.0
Optional thickness

volume-static-moments 3d vector (ie 3d point)

Returns the Volume Static Moments of the face.

keyword arguments:
desired-accuracy Number, Default Value: 1.0e-6
Desired accuracy of result. Should not be smaller than 0.00000001 (10e-08)
face-thickness Number, Default Value: 0.0
Optional thickness

Package Documentation