VARKON Version 1.15 1997-10-16
A point is a geometric entity occupying a specific position in space.
Points are created using one of the following methods....
poi_proj(id,p1);
poi_free(id,p1);
The proj version indicates that position p1 is projected onto the XY-plane
of the active coordinate system before the point is created. The free version
creates a point anywhere in 3D space.
There is also a proj and a free version of the line entity....
lin_proj(id,p1,p2);
lin_free(id,p1,p2);
A line entity is always straight and limited. There are no infinite or
semi infinite line entities in VARKON. (If you need something with direction
and infinite length you can use the VECTOR datatype). Other ways to create
a line are....
lin_ang(id,p1,angle,length); ! From p1 with angle and length
lin_offs(id,other_line,distance); ! Offset to other line at distance
lin_perp(id,p1,other_line,length); ! From p1 perpendicular to other
line
lin_tan1(id,p1,other_entity,alternative); ! From p1 tangent to arc
or curve
lin_tan2(id,other_entity_1,other_entity_2,alternative); ! Tangent
to two arcs
The parameter named alternative in lin_tan1 and lin_tan2
is used to distinguish between different possible solutions. In lin_tan1
for example it could very well be the case that a straight line from p1
can find more than one point of tangency on a curve or arc. For a closed
circular arc there is always two points of tangency and for a curve that
oscillates there could be more than two.
VARKON enumerates solutions (tangency points) in the order they appear
when traveling along the curved entity in its right sense of direction
and the parameter named alternative above is then used to select the right
solution. A 1 for the first, 2 for the second and so on.
A line can be converted to a curve using cur_comp.
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