I’m a bit confused about construction lines vs construction points.
The ConstructionLine docs mention both infinite, finite and semi-finite lines, but I can’t find a way to create finite or semi-finite guidelines from the UI. There is a code example for creating a finite guide line but I can’t remember ever having seen something like it in SU. Can these not be created from the UI?
A ConstructionPoint on the other hand can be created from the UI with a “trail” line, if you click on vertex with Tape Measure and then somewhere in space. However, a construction point with a line/vector doesn’t seem possible to make through the API.
Is there an overlapping responsibility of these classes and confusion of what they should be used for?
I use a construction line plugin which draws finite guides, and optionally endpoints ( cpoints). Not at computer now, but when I am I’ll send you the plugin code.
Of course, the starting method is Entities#add_cline. The API docs only mention the infinite (provide a point and a vector to define the line) and the finite (provide a start point and an end point) varieties. I believe (but can’t check just now) you can make a semi-infinite guide line via the API by first creating an infinite cline and then setting either its start or end. I don’t think the GUI provides a way to create either a finite or semi-infinite guide line.
In the API you can replicate the visual effect of a guide point with a tail by creating a cpoint and then a finite cline from the reference point to the cpoint location. However, unlike in the GUI, they won’t be treated as a single thing and the finite cline will be selectable.
If add_cline() is given two points it draws a cline between them.
But when it is given a point and a vector it [initially] makes an infinite cline in both directions, but then you can set either its start or its end point to make if infinite in one direction only.
Obviously setting both a start and an end point is like making it a fixed length cline initially…