Using Blender for VWT CAD

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Using Blender for 3D Design Entry

You can download Blender from http://www.blender.org for Linux or Microsoft Windows. It is free Open Source software. Note on Microsoft Windows you will also have to install Python 2.5.2 as prompted from the blender install. You may also need to install a Microsoft Windows Update.

Blender is quite a sophisticated 3D drawing and animation package. Blender is not really a 3D engineering CAD, it has a "unique" GUI and takes a little getting used to but works well for this purpose.
When generating a Greenpower car design for the Virtual Wind Tunnel, make sure the design is scaled correctly (2.5 meters long etc) and located above 0 in the Z direction (height) and centered at X=0 and Y=0.

Notes on using Blender:
  • Blender cannot handle the Microsoft UNC file paths as used with network servers. These are file paths like "\\css.net\dir". In order to access these files these network paths need to be mapped to a local drive letter. This can be done in "Windows Explorer" under the "Tools" menu bar item as well as in other ways.
  • The middle mouse button (Or both buttons pressed if you have only two buttons) moves the drawing view. Used with the CTRL or SHIFT keys restricts the movement to the X/Y or zoom in/out. The mouse Wheel also works.
  • The right hand button selects things.
  • A Box selection can be made using the "b" key followed by clicking and dragging with the LHB.
  • All items can be selected or not selected by using the "a" key.
  • The Left hand button is used to move, scale, rotate etc. This also has a "gestures" mode which I have not tried.
  • The "View" menu item allows the view to move to the front, side and top. Note for our use the "front" will be the side of the car. The Numeric keypad keys also allow the view to be changed (7 - Plan, 1 - Side, 3 - Rear).
  • I find it easiest to have a single view window opened. The Windows can be split or joined by clicking with the RHB near the edges of the window and using the little pop up menu that appears.
  • The system can be in Object mode or Edit mode, selected using the "TAB" key or the mode combo box.
  • When in Object mode the object can be manipulated as a whole. The G key moves, S key scales etc. If you press "G X" the the movement will only be in the X direction etc. After pressing G, GX, GY etc you can use the mouse to drag the object or type in a dimension in meters.
  • When in Edit mode you can manipulate the vertices, edges or faces of the object. Again you can select one or more items and then move, scale or otherwise transform them.
  • Pressing "Space" will bring up a menu of operations. Pressing "w" will bring up another special menu. These include extrusion etc.
  • Objects can be grouped together to form complex single objects such as a wheel with a tyre. Select the objects and then use the "Join" command "CTRL-J" available from the "Object" menu acceseesd using "Space". Note that if an oject is selected and another object is added to the design, it will automatically become joined to the selected object.
  • A wheel can be constructed with a torus and two cones as done in the Rotary Racer RR3 design.
  • You can import objects from another design file. Use the "Append or Link" button on the "File" menu.
  • When moving, scaling or rotating a value can be entered by simply typing in the number. Note that 1.0 is 1meter.
  • You can add bits by using the "Add/Mesh" or "Add/Surface" menu entries. Note that if an object is selected when an object is added to the design, it will automatically become joined to the selected object.
  • The "n" key brings up a box defining the diemtions and name of the object. The objects size and position can be changed.
Notes:
  • When exporting the STL make sure that all of the cars design is selected (use the "a" key). Also make sure that the file name has a ".stl" extension.
  • On systems which have slow 3D graphics, you can view the design in wire mesh form while designing it. Use the "Viewport Shading" combo box to change this.
  • You can download the example car files from the link above. The Blender files have a ".blend" extension.
Misc: