Geometry - basic building blocks
| geometry | examples of manifestations | parameters |
|---|
| points |
| x/y/z coordinates |
| curve geometry | | - vertices
- control points
- degree
|
| surface geometry (NURBS) | |
|
| solids | |
|
| meshes / polygons | | |
Boundary representation (BREP)
| geometric entities | topological |
|---|
| point | vertex |
| line | edge |
| surface | face |
Rhino Interface
Setup:
- Turn on Point Snap (End, Midpoint, Center, Intersection, Perpendicular, Quadrant) & Grid Snap
- Turn on Gumball
- Turn on shading for the perspective window (shaded or ghosted)
- Tip: Enter or Space to enter commands
First Steps in Rhino
| What | How | Visual Aid |
|---|
| navigating | - Pan (two finger swipe/right mouseclick + Shift - also Control + Shift + click and drag)
- Zoom (pinch)
- Rotate View (two finger swipe/right mouseclick - also Control + click and drag
|
|
| selection | depending how you drag your selection window either everything touched by the selection window is selected (bottom right to top left) or only objects that are fully enclosed by the window are selected (top lect to bottom right) |
|
| create geometry | _line
_curve
_circle
_arc
_rectangle | |
| edit 2D | _move
_copy
_rotate
_scale
_dir (flip direction)
_array | |
| _join
_eplode
_trim
_split
_group
_ungroup _extend
_mirror | |
| edit with gumball | Turn on control points Turn on gumball - select control points or geometry and use handles to move, rotate or scale
- extrude: drag move handle then hold Command
- to select contour: Command + Shift + select contour
| |
| create 3D geometry | primitives: _pipe
_box
_sphere
_cylinder operations: _sweep
_loft
_rail
_revolve
_extrude | |
| boolean operations | _BooleanUnion
_BooleanDifference
_BooleanIntersection |  |
| use a reference image | _BackgroundBitmap |
|
Exercise 1:
Reproduce the 2D form, and revolve it into a 3D solid
Commands:
- draw line; turning on gridsnap makes things easier
- join the line, if it is not a joined line already
- use _fillet to create the round inner edge
- revolve contour to create a 3d solid
Exercise 2
Transform and extrude a 2D form using the gumball tool.
Tip: holding command (windows ctrl) after dragging an arrow will extrude in that axis.
Exercise 3
Reproduce the form from this technical diagram.
Commands:
- Offset to offset the boundary of a curve
- Split and Trim to edit lines, curves and polylines
- Object snap tangent to draw a line from a curve edge
- Extrude to create 3D geometry from 2D
- SrfPt to create a non-planar surfaces
- Spit to cut a solid with a surface or curve
- Boolean Union to combine all geometry
- MergeAllFaces to clean up surfaces
