Thinking about doing a LDCad 1.7 version

[N. W. Perry]

I realized if you assume all selection points are on a plane, you can drop the setX/setY lines and calculate the plane normal instead of using a static x vector

Code:

function onRun()   local sel=ldc.selection()   if sel:getRefCount()<3 then     return   end   local a=sel:getRef(1):getPos()   local b=sel:getRef(2):getPos()   local c=sel:getRef(3):getPos()   local ba=a-b   local bc=c-b   local n=bc:getCross(ba)   n:normalize()   local bb1=n:getSignedAngle(ba, bc)   local bb2=math.deg(math.acos(bc:getLength()/ba:getLength()))   local angle=-(bb1-bb2)   ldc.setClipboardText(angle)   ldc.dialog.runMessage(angle) end

neg y makes it somewhat confusing but i think this should work in any orientation, not tested though.

This version got me close, but not quite: