A tiny subset of unmissable CAD functions for Blender 3d.
Addon page on blender.org/wiki (Which has most of the same info)

Dedicated CAD software speeds up drafting significantly with functions like: Extend, Trim, Intersect, Fillet /w radius and Offset /w distance. At the moment of this writing many of these functions aren't included by default in regular distributions on Blender.org, so i've coded scripts to perform a few of the main features that I missed most.

My scripts have shortnames: VTX, V2X, XALL, BIX, CCEN and are described separately in sections below. Fillet and Offset are written by zmj100 and can be found here.

The VTX script has lived in contrib distributions of Blender since 2010, with relatively minor changes. The feedback from BlenderArtists has been overwhelmingly positive. I'm not going to claim it's bug free, but finding any showstopping issues has proven difficult. It now performs V, T or X selection automatically.

Expect full freedom of orientation, but stuff must really intersect within error margins (1.5E-6 = tolerance). These kinds of functions are handy for drawing construction lines and fixing up geometry.

• V : extending two edges towards their calculated intersection point.
  

• T : extending the path of one edge towards another edge.
  

• X : two edges intersect, their intersection gets a weld vertex. You now have 4 edges and 5 vertices.
  

• Select two edges

• hit Spacebar and type vtx ..select autoVTX

• Bam. the rest is taken care of.

Intersect all, it programatically goes through all selected edges and slices them all using any found intersections, then welds them.

• XALL is fast!
  
• Select as many edges as you want to intersect.
• hit spacebar and type xa ..select XALL intersect all edges

This might be a niche accessory, but sometimes all you want is a vertex positioned on the intersection of two edges. Nothing fancy.

It has two modes.

• Pick an edge (we'll call this Edge Prime)
• make sure only one edge is selected
• Run EXM extend multiple edges from spacebar menu
• Your picked edge has turned light blue
• Pick edges to extend towards that edge
• If edges are picked that don't intersect in 3d space (within tolerance) then those edges are not added
• Edges that do intersect will be shown in a different colour with the extended part in yet another colour
• You can unpick edges by clicking on them
• To finalize the operation:
  - Press Comma to extend the edges using the vertex closest to the intersection point by moving the vertex closest to the edge being extended towards. - Press Period to create a new edge attached to the original geometry.
• This addon does not weld the extended edges onto Edge Prime.

Creates a single edge which is the bisect of two edges.

Given either

• two adjacent edges on the circumference of an incomplete circle
• or two vertices (not required to be adjacent)

this operator will places the 3d cursor at original center of that circle.

updated version may become a modal operator to generate a full set of circle vertices, with variable vertex count.

Explained in the issue tracker with moving GIF: issue3

The issue tracker, use it.

• Let me know if these things are broken in new releases. Why? I don't update Blender as often as some so am oblivious to the slow evolution.
• If you can make a valid argument for extra functionality and it seems like something I might use or be able to implement for fun, it's going to happen.
• I'm always open to pull requests (just don't expect instant approval of something massive, we can talk..you can use your gift of persuasion and sharp objectivism)