Primitives and properties

6.2. Primitives and properties

General properties


These properties apply to all primitives. The names of the properties along with their default values and a short description are shown below. Note that figures do not necessarily represent the default values of the properties.
`longname`	`["Unnamed"]`	-- friendly name for the object
`iappear`	`[""]`	-- individual appearance
`iscale`	`["1 1 1"]`	-- individual scale (vector)
`irotv`	`["0 0 1"]`	-- individual rotation axis (vector)
`irota`	`[0]`	-- individual rotation angle (degrees)
`ipos`	`["0 0 0"]`	-- individual position relative to attachment point (vector)
`appear`	`[""]`	-- appearance of this and attachments
`scale`	`["1 1 1"]`	-- scale of this and attachments (vector)
`rotv`	`["0 0 0"]`	-- rotation axis of this and attachments (vector)
`rota`	`[0]`	-- rotation angle of this and attachments (degrees)
`pos`	`["0 0 0"]`	-- position of attachment point (vector)
`icolor`	`[""]`	-- individual color.
`iecolor`	`[""]`	-- individual appearance -- edge color.
`iscolor`	`[1]`	-- individual appearance -- same color?
`ishade`	`["default"]`	-- individual appearance -- shading.
`iedges`	`["default"]`	-- individual appearance -- draw edges?
`ifaces`	`["default"]`	-- individual appearance -- draw faces?
`iewidth`	`[""]`	-- individual appearance -- edge width.
`color`	`[""]`	-- color of this and attachments.
`ecolor`	`[""]`	-- group appearance -- edge color.
`scolor`	`[1]`	-- group appearance -- same color?
`shade`	`["default"]`	-- group appearance -- shading.
`edges`	`["default"]`	-- group appearance -- draw edges?
`faces`	`["default"]`	-- group appearance -- draw faces?
`ewidth`	`[""]`	-- group appearance -- edge width.

Common properties

These properties appear in many primitives.

angle [60] -- arc in XY plane between struts

This property is used in trusses where there is a circle at one end and the struts of the truss may be separated at that end. The angle is half the measure of the arc (in degrees) that the ends of the struts make in the plane. Possible values for this property range from 0 to 60 degrees.

Below are examples of a CirCirTruss viewed from above with edges colored black, shown with varying values for the angle.

at 60 degrees
at 55 degrees
at 5 degrees
at 0 degrees

angle [0] -- angle of twist between ends

This property is used in trusses where both ends are the same shape and one is rotated in relation to the other. For rectangular ends, values of this angle range from 0 to 90 degrees. For triangular ends, values range from 0 to 120 degrees.

Below are examples of a RecRecTruss viewed from above with edges colored black, shown with varying values for the angle.
at 0 degrees
at 5 degrees
at 45 degrees
at 60 degrees

fraction [.5 or .3] -- location of the line relative to the width of the other end

This property is used in trusses where one end is a line. It determines where to place the line in relation to the other end. It represents a fraction of the bottom width. There are not limits on what the value of the fraction may be. A value of "0" means directly over the left side; a value of "1" means directly over the right side.

The following examples show varying values of the fraction for a LinRecTruss viewed from above with edges colored black.

fraction = -0.1
fraction = 0.0
fraction = 0.5
fraction = 1.0
fraction = 1.1

res [24] -- resolution of circle

This property is used on objects that have some curvature that is smoothly shaded. Cylinder, Sphere and Torus are some examples where this property is used. By default a circle is drawn with 24 segments. Changing this value changes how many segments make up a 360 degree circle. This is useful for saving drawing time if higher resolution is not needed.

The following examples show what a Sphere looks at different resolutions.

res = 24
res = 12
res = 4