Model Shape defines a visual shape that is shown at the location of its reference coordinate system, called 'object frame' below. All describing variables such as size and color can vary dynamically (with the only exception of parameter shapeType). The default equations in the declarations should be modified by providing appropriate modifier equations. Model Shape is usually used as a basic building block to implement simpler to use graphical components.
The following shapes are supported via
parameter shapeType (e.g., shapeType="box"):
The dark blue arrows in the figure above are directed along
variable lengthDirection. The light blue arrows are directed
along variable widthDirection. The coordinate systems
in the figure represent frame_a of the Shape component.
Additionally, external shapes can be specified as (not all options might be supported by all tools):
The supported file formats are tool dependent. Most tools support at least DXF-files but may support other format as well (such as stl, obj, 3ds). Since visualization files contain color and other data, the corresponding information in the model is usually ignored. For information about DXF files, see Wikipedia. As a default it is assumed that the DXF coordinates are in the "frame_a"-system and in meters, and that the 3dfaces are two-sided. Some tools support only 3dface (for geometry) and layer (for advanced coloring).
The sizes of any of the above components are specified by the length, width and height variables. Via variable extra additional data can be defined:
shapeType | Meaning of parameter extra |
---|---|
"cylinder" | if extra > 0, a black line is included in the cylinder to show the rotation of it. |
"cone" | extra = diameter-left-side / diameter-right-side, i.e., extra = 1: cylinder extra = 0: "real" cone. |
"pipe" | extra = outer-diameter / inner-diameter, i.e, extra = 1: cylinder that is completely hollow extra = 0: cylinder without a hole. |
"gearwheel" | extra is the number of teeth of the (external) gear. If extra < 0, an internal gear is visualized with |extra| teeth. The axis of the gearwheel is along "lengthDirection", and usually: width = height = 2*radiusOfGearWheel. |
"spring" | extra is the number of windings of the spring. Additionally, "height" is not the "height" but 2*coil-width. |
external shape | extra = 0: Visualization from file is not scaled. extra = 1: Visualization from file is scaled with "length", "width" and "height" of the shape |
Parameter color is a vector with 3 elements, {r, g, b}, and specifies the color of the shape. {r, g, b} are the "red", "green" and "blue" color parts. Note, r, g, b are given as Integer[3] in the ranges 0 … 255, respectively. The predefined type MultiBody.Types.Color contains a menu definition of the colors used in the MultiBody library together with a color editor.
The dialog variables shapeType
, R
, r
, r_shape
,
lengthDirection
, widthDirection
, length
, width
,
height
, extra
, color
, and specularCoefficient
are declared as (time varying) input variables.
If the default equation is not appropriate, a corresponding
modifier equation has to be provided in the
model where a Shape instance is used, e.g., in the form
Visualizers.Advanced.Shape shape(length = sin(time));