Scene Graph APIs | | Hierarchical Modelling

Blender is a free scene graph modelling and rendering application. It applies many concepts outlined in the previous lecture. Primarily it is used to create CGI movie films, but it can also be used to model 3D scenes and export them in the Wavefront OBJ format, so that it can be imported into other OpenGL applications and game engines.

It is recommended to use Blender 2.79 or later.

Here is a short overview of the most important modeling commands in Blender:

  • Middle mouse button: rotate view
  • Shift middle mouse button: move view
  • Ctrl middle mouse button: zoom view
  • Mouse wheel: zoom view
  • Numpad 1–9: Select various views (need to enable numpad emulation in preferences)
  • Ctrl Alt 2-finger trackpad: rotate horizontally
  • right click: select object
  • Shift right click: select multiple objects
  • Ctrl mouse: lasso selection
  • Key a: select resp. deselect all objects
  • Key b: box selection tool
  • Key g: grab selected object and translate it
    • Key Alt-g: reset object translation
    • Key s: scale the grabbed object
    • Key Alt-s: reset object scaling
    • Key r: rotate the grabbed object
    • Key Alt-r: reset object rotation
    • Key x: restrict modifications to the x-axis
    • Key y: restrict modifications to the y-axis
    • Key z: restrict modifications to the z-axis
    • Key Alt-x: restrict modifications to the yz-axis
    • Key Alt-y: restrict modifications to the xz-axis
    • Key Alt-z: restrict modifications to the xy-axis
    • Key x r 9 0: rotate the grabbed object 90 degrees about the x-axis
    • Key x s −1: mirror the grabbed object along the x-axis
    • ESC: revert modifications
    • Enter: confirm modifications
  • Key u: uv unwrap (with edges marked as seams)
  • Key z: show wireframe, x-ray mode etc.
  • Key n: show properties
  • Key Tab: enter edit mode
    • Key e: extrude selected face
    • Key i: inset selected face
    • Key Ctrl-r : add loop cut to selected object
  • Key Shift-s: align 3D cursor
  • Key Shift-a: add new object
  • Key Shift-d: duplicate selected object
  • Key Ctrl-p: define parent-child relationships (last selected object becomes the parent)
  • Key Ctrl-s: save to .blend file
  • Key Ctrl-z: undo

Custom key shortcuts: For example, we can set a custom keyboard short cut to add a modifier (like subdivision surface). So we set up the custom shortcut to call “object.modifier_add”, and that will make the modifier menu appear.

Scene Graph APIs | | Hierarchical Modelling