Editing BRL-CAD Primitives
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[[category:MGED| Primitives]] | [[category:MGED| Primitives]] | ||
− | + | These are primitive objects that can be created in mged. | |
− | + | Objects can be created in any of the following ways: (note: are there more? get? load from file?) | |
− | + | ;make : the mged make command creates the object with default dimensions | |
− | * | + | ;in : the mged in command interactively prompts for dimensions not already supplied as arguments |
− | + | ;form :the graphical primitive editor form (* some objects not fully supported) | |
+ | ;create : the graphical create menu | ||
− | + | When an object is selected from the create menu, you are prompted for a name, and then dropped into the primitive editor form; however, if the objec type has no form, create will do about the same as make. Some derivative objects do not have their own form, and the primitive editor will use the base object's form. Most parameters (including ones not editable from a form) have special items on the edit menu. | |
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− | ; | ||
− | + | See also [[A Survey of Implicit Constraints in Primitives]] | |
− | + | =Arbs= | |
+ | Objects with an arbitrary number of points and flat faces... | ||
+ | ==arb8== | ||
+ | Arbitrary straight-edged shape with 8 vertices. | ||
− | + | ;Handled by: make in form create | |
+ | ;Arguments: 8 Vertices in the following order: 1234 vertices for the front face, starting at bottom left, counterclockwise; then 5678 vertices for the rear face, starting at bottom left, counterclockwise. | ||
+ | ;Example: | ||
+ | in unitcube.s arb8 0 0 0 1 0 0 1 0 1 0 0 1 0 1 0 1 1 0 1 1 1 0 1 1 | ||
+ | creates the unit cube (first vertex at the origin, extends for 1 unit in x, y and z direction). | ||
− | + | == arb7 == | |
− | + | Special case of arb8, except with point 8 merged into point 5, making the left face triangular | |
− | + | ;Handled by: make in form(arb8) create | |
+ | == arb6 == | ||
+ | Arbitrary straight-edged shape with 6 vertices, special case of arb8. | ||
+ | ;Handled by: make in form(arb8) create | ||
+ | ;Arguments: 6 Vertices in the following order: 1234 vertices for the front face, starting at bottom left, counterclockwise; then back edge is 5 on bottom, 6 on top. Top and bottom faces are triangles. | ||
+ | ;Example: | ||
− | + | in arb6.s arb6 1 -1 -1 1 1 -1 1 1 1 1 -1 1 -1 0 -1 -1 0 1 | |
− | == | + | == arb5 == |
+ | special case of arb8. | ||
+ | ;Handled by: make in form(arb8) create | ||
+ | == arb4 == | ||
+ | special case of arb8. | ||
+ | ;Handled by: make in form(arb8) create | ||
+ | == arbn == | ||
+ | Arbitrary solid bounded by N planes. | ||
+ | ;The solid is constructed by N sets of plane coefficients and distance magnitudes, that define space which is ~outside~ the solid. The coefficients define a vector whose normal is a plane parallel to the face of the solid. The surface of the solid is at the perscribed distance along this vector. | ||
− | An | + | The distances may be negative and are used when a face lies on the opposite side of the origin as the tip of its vector. An example is if the left side of a box lies on the positive X axis. In this case, because the left side is being defined, the vector points left (coefficients -1 0 0), but since the point is on the positive X axis its distance is opposite its vector and therefore negative. |
− | + | ;Handled by: make in create | |
− | + | ;Arguments | |
− | + | :Number of planes | |
− | + | :xyz direction vector and distance for each plane | |
− | + | ;Example | |
+ | :in arbn.s arbn 8 1 0 1 1 -1 0 0 1 0 1 0 1 0 -1 0 1 0 0 1 1 0 0 -1 1 0.5 0.5 0.5 1 -0.5 -0.5 -0.5 1 | ||
− | + | ;Example with negative distance | |
− | + | :in arbn2.s arbn 6 1 0 0 100 -1 0 0 -10 0 1 0 200 0 -1 0 -10 0 0 -1 0 0 0 1 1.5 | |
+ | :...is equivalent to... | ||
+ | :in rpp.s rpp 10 100 10 200 0 1.5 | ||
− | + | ==box== | |
+ | Special case of arb8 | ||
+ | ;Handled by: in form(arb8) | ||
+ | ;Arguments: Vertex of first corner, direction vectors for height, width, and depth | ||
− | + | ==raw== | |
+ | Right Angle Wedge, special case of arb6 | ||
+ | ;Handled by: in form(arb8) | ||
+ | ;Arguments: Vertex of first corner, direction vectors for height, width, and depth | ||
− | == | + | ==rpp== |
− | + | Rectangular Parallelpiped, special case of arb8 | |
− | + | ;Handled by: make in form(arb8) create | |
− | + | ;Arguments: xmin xmax ymin ymax zmin zmax | |
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=Ellipsoids= | =Ellipsoids= | ||
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;Handled by: in create | ;Handled by: in create | ||
;Arguments: data type (f|o), datasource, count of length and width, interpolation type, cut direction, cell size, unit elevation | ;Arguments: data type (f|o), datasource, count of length and width, interpolation type, cut direction, cell size, unit elevation | ||
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==ebm== | ==ebm== | ||
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− | == | + | ==nurb== |
− | + | Non-uniform rational b-spline | |
+ | ;Handled by: none? | ||
==spline== | ==spline== | ||
surface splines | surface splines | ||
− | ; | + | ;Handeld by: ? |
==vol== | ==vol== | ||
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;Handled by: make form(sketch editor) create | ;Handled by: make form(sketch editor) create | ||
;See also: [[sketch]] | ;See also: [[sketch]] | ||
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==grip == | ==grip == | ||
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;Arguments: minor type (fdcsiLCSIL), data file, number of values | ;Arguments: minor type (fdcsiLCSIL), data file, number of values | ||
− | + | [[Determining the properties of primitives]] | |
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