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TrueTangents    v3.0

  • Quick Start
  • Release Notes

How to use True Tangents

  • Select an arc/circle and a cpoint (aka guide-point)

  • Run truetangents in the ruby console or via Plugins > Tangent Tools > True Tangents

True Tangents Example

NOTE: On errors - e.g. no arc selected or the cpoint is inside the circumference - there is a console message.

It then draws construction points at the arc-centre, circumference and the 2 tangent points, and construction lines on the two radii and tangents. It draws to the true tangent points - these might not be on the arc itself if it's lightly segmented - now you can rotate, entity-info increase segments or reconstruct the arc as desired so it passes through a tangent point.


How to use Common Tangents

  • Select an arc/circle

  • Select a second arc/circle

  • Run commontangents via the ruby console or via Plugins > Tangent Tools > Common Tangents

NOTE: On errors - e.g. 2 arcs not selected or a circle within another circle can have no common tangents - there is a console message.

It then draws cpoints at the arc-centres, circumferences and tps, and clines on the four radii and two/four tangents - it draws to the true tps - these might not be on the arc itself if it's lightly segmented - now you can rotate, entity-info increase segments or reconstruct the arc as desired so it passes through a tp... Different forms of common tangent are produced if the arcs are separated by clear space or intersect (4 or 2 nr).


How to use True Intersections

  • Select an arc/circle

  • Select a constrution line OR a second arc/circle

  • Run trueintersections via ruby console or via Plugin > Tangent Tools > True Intersections

NOTE: On errors - e.g. non-intersecting arcs/clines - there is a console message.

It then draws 2 construction points at the true intersections of the arc and the construction line [OR the 2 arcs]; it also adds further centre-points, construction lines etc and additional true mid-points on the circumference to aid with later arc recreation if desired: special cases produce other drawn results - e.g. construction line is a diameter, arcs just kiss or touch at one point...


How to use Tangential Arcs

  • Select a Line and an Arc or Circle

  • Run tangentialarcs

NOTE:On errors - e.g. non-intersecting arcs/clines - there is a console message.

It then draws cpoints at the centers of the two tangential-arcs [or one tangential-arc and another looped tangential-arc] and at their tangent-points etc, [messages in console], it also adds clines on the radii to the tangent points-etc. If the line is tangential to the arc or if the tangential arc's radius would be > the arc_radiusx100 or smaller than 1/100th then no cpoint is drawn at the center because it might be many miles away and effect the model's extents - instead a cline is drawn between the line end and tangent-point and a console message suggests you might like to draw a straight line instead... The tangential arc cpoints etc are added at the end of the line nearest to the arc, unless that end is on the circumference, then the other end is used. Internal lines also have tangential-arcs and are created similarly at the end nearest the circumference unless it's touching it...


How to use Fillet Arc

  • Select an arc/circle and a cline/line (aka guide-line)

  • Run filletarc via ruby console or via Plugins > Tangent Tools > FilletArc

NOTE: On errors - e.g. no arc selected - there is a console message.

Enter the required fillet radius in the dialog that appears. If the line doesn't intersect the arc and the fillet radius won't work then you are told and the dialog reopens giving the minimum radius that will work. Assuming the radius is valid then it draws cpoints at the arc-centre, the new fillet arcs' centers and all of the the true tps, with clines on the each of the two radii and the chord linking the pairs of tps - note how these might not be on the arc itself if it's lightly segmented - there are 4 or 8 possible fillet arcs depending on whether or not the line intersects the selected arc, draw over the one(s) you want using the 2D Arc / Circle Tool etc.

v1.1 - now adds all 4 common-tangents for non-overlapping circles

v1.2 - glitch on some external common-tangents permutations fixed

v1.3 - additional cpoints added at circumference intersections to aid arc redraw though 3 points if needed

v1.4 - extra cpoints/clines added to opposite circumference intersections to aid arc redraw in other direction

v1.5 - true intersections added for arc+cline OR arc+arc

v1.6 - tangential arcs added for line+arc

v1.7 - fillet arc added for arc/circle + line/cline, dialog to enter fillet radius

v1.8 - missing 5th menu item fixed

v1.9 - sub-menu 'Tangent-Tools...' added

v2.0 - tolerance added on the coplanar check for arcs

v3.0 - Float 'n1=~n2' replaced with 'eq(n1,n2)' avoiding potential clashes.