Construction Lines - Accurate Cad Modelling Add-On For Blender

On Sale! by Dan Norris in Scripts and Addons

CAD Modelling for Blender

Overview And Key Functions

Construction Lines is a tool for accurate CAD style modelling. Build snappable guide points and edges, draw lines and primitive shapes in place, automatically create faces in closed geometry and precisely move object geometry around a scene.

Guide edges and points allow for a construction workflow where guides are set and models are then constructed within these guides. The guides won't interfere with model geometry and can be toggled off and on when required. Guides edges will disappear when working outside of Construction Lines and neither Guide Edges nor Guide Points will be rendered. 

Construction Lines allows for rectangles, circles, and arcs to be drawn in place from precise snap points on existing geometry or guides. These can be drawn from anywhere on a 3D model without the need for Blender's 3D cursor to define an Add location. Drawing shapes onto existing faces will automatically cut into the existing face. 

Construction Lines works seamlessly between Object and Edit modes in Blender.

If you come from software packages such as SketchUp this is a perfect way to get started with Blender

NOTE: Construction Lines is currently in Beta and is regularly updated with fixes and improvements.

Price Reduced in Beta


**New Feature (version 0.9.4) - Cut into existing faces 


Guide Edges & Points

Drawing Lines


Drawing Shapes In Place


Precise Object Moving 



Feature List

  • Create snappable guide edges and points
  • Precisely measure distances
  • Build rectangles, circles and arcs anywhere in your scene
  • Draw lines simply by clicking and dragging in the 3D viewport
  • Lines will automatically fill in faces where geometry is closed
  • Use lines or shapes to cut into or divide existing geometry 
  • Build lines, shapes and guides to exact size with numeric input (including mathematical operators * / + -)
  • Limit drawing and movement to  the X, Y or Z axis
  • Auto snap to Perpendicular edge direction and edge extensions
  • Accurate object movement with snap points or numeric input
  • Create faces from a list of selected snap points (vertex, edge, edge center, face)
  • **New feature - Cut into existing geometry by drawing onto existing faces (Construction Lines will automatically create the extra required geometry), allowing shapes to be extruded in and out of existing meshes.


Features In Development

  • Angle measurement between objects/geometry points
  • Rotation of guidelines/objects to a snapped point - means you can rotate and snap to a distant unconnected vertex/edge/face
  • Dragging guides/objects locked perpendicular to an existing guide edge or geometry edge


Current Version

Version 0.9.41

Release Notes:

Updates & Bug Fixes:

  • Fixed failure to split face when drawing lines onto an existing face
  • Fixed bug where shapes could not split an existing face, after the face had already been split by a line
  • Normals of new shape or line drawn faces are now correctly oriented to view
  • Display text now displays the current modelling mode (Object or Edit mode)


Version 0.9.4

Release Notes:

Features & Updates:

  • New feature to allow for circle, rectangle and line-drawn faces, to cut holes into existing faces. New geometry is automatically created to allow this to happen away from existing edges.
  • Big improvement to edge snapping, snap point no longer runs away from the cursor
  • Changed lower limit to guide scale in preferences to 0.0001
  • Guide edges now have a scaling preference. The value is from 1-5
  • New text display in the bottom left of Viewport to show which tool/action is currently running
  • Support now for Blender 2.9


Bug Fixes:

  • Fixed Arc direction snapping and locking
  • .(dot) on the Numpad now works correctly for decimal input (azerty keyboard issues)
  • Fixed issue with Construction Lines not working after loading a file which has been saved during Construction Lines use. A running flag was saved into the file, so Construction Lines thought it was still running
  • Fixed issue when creating a new object, deleting it and undoing the action multiple times. Construction Lines on occasion would still keep a reference to some deleted objects
  • Improved face finding and creation on existing meshes
  • Fixed issues when axis snap overrides snapping to a geometry point. These two snaps work together now
  • Calling undo whilst in edit mode will now remain in edit mode rather than object mode
  • Fixed issue when using imperial units sometimes failing with multiple digits before a decimal place, in numerical input


Version 0.9.3

Release Notes:

Features & Updates: 

  • Snapping can now occur when line/tape is dragged perpendicular or is an extension to an edge (snap is highlighted for both cases - pink for perpendicular and purple for edge extension)
  • Numeric input is now triggered after the Enter key is pressed. This allows for the Numpad and number row to be used for camera orientation during normal operation. Pressing Enter again, after typing a value, will apply the number/expression to the current operation
  • Select a guide edge and create true geometry for use outside of CL using the context menu (hold Shift and click guide edge to select. The guide will change to an orange colour when selected )
  • Added new preference to override Unit Length with Unit Scale when adding guides and new geometry (this is useful when working with custom scales)
  • Added new preference to set guide scale. This will affect all new guide points. Existing guides can be updated by using Scale All from the context menu
  • Default scale for guide points is now smaller
  • 3D mouse events are now passed through to Blender, so using a 3D mouse to navigate should now be possible
  • Strength of axis snapping has been reduced, allowing for greater freedom of movement when drawing and measuring


Bug Fixes:

  • Fixed OpenGL issue with dashed tape measure not displaying on some Apple Mac computers
  • Fixed bug when calling undo multiple times, where undo will lead outside of current Blender context and cause a crash
  • Fixed issue with correct measurement display when changing length units
  • Fixed bug which allowed some non-numeric values to be used in metric mode input, causing a crash
  • Fixed issue with numeric input when using Imperial units and typing a number with greater than one decimal place as the first value
  • Mouse clicks outside of viewport area are now handled correctly (either passed through to Blender or ignored)
  • RGB values for guide colour in preferences are now correctly limited
  • Numerous performance and stability improvements along with lots of minor fixes


Version 0.9.2

Release Notes:

  • Big performance improvements when cutting into existing geometry
  • Fixed stability issues when using shapes to cut into existing geometry


Version 0.9.1

Release Notes:

Minor update

Please note that upgrading from version 0.9.0 requires removal of version 0.9.0 from Blender before installing any new version. 

  • Dimension input now allows for Imperial values (when Blender's Unit System is set to Imperial) - Values can be written in multiple ways eg. 12'1" 3/8, 12'1, 12' 3/8, 12. Decimals can be used for the first value. Will work with either Feet or Inches set as the Length Unit
  • Hold Ctrl and using the mouse wheel will allow for changes in circle/arc segments and will also automatically add guide point divisions to the current guide edge - Whilst dragging a guide edge use Ctrl+Mouse Wheel to increase/decrease the number of guide divisions
  • A guide point is now added to the start of a guide edge
  • Bug fix to arc and circle when using with existing geometry face - was not cutting correctly - NB. This is a patch fix, the face finding and face intersection system will be re-written for the next Construction Lines Version
  • Bug fix to measurement scale - was not previously taking into account the user-entered Unit Scale only unit type scale 

Inital Version

Version 0.9.0 Initial Beta Release