Rhino and Grasshopper

Basic Rhino Workflow

1. Create Reference Geometry

Before creating solid forms, begin by sketching the basic geometry in 2D. Usually this is done in the Top View viewport.

Drawing Initial Geometry

• Use the Line command to draw the first component.

• Start at a known coordinate such as 0,0.

• Type exact distances or coordinates into the command line for precision.

Example:

• Start line at 0,0

• Type 100,0 to create a 100 mm horizontal line.

Creating Reference Construction

Use the first geometry to construct the rest of the sketch.

Useful commands:

• Line

• Polyline

• Offset

• Copy

• Extend

• Trim

Tips: - Turn on Osnap to snap precisely to:

• End points

• Midpoints

• Intersections

• Centers

• Use reference lines to locate:

• holes

• supports

• mounting points

• symmetrical features

• Construction geometry can later be deleted or moved to a separate layer.

---

2. Creating Solid Forms

Once the sketch is complete, use it to build 3D geometry.

Primitive Shapes

Simple geometry can often be made using predefined solids:

• Box

• Cylinder

• Sphere

• Cone

These commands usually ask for:

1. Base point
2. Size dimensions
3. Height

Example:

• Use Box

• Select first corner

• Type dimensions

• Enter height

---

Create Custom Geometry

More complicated forms usually follow this workflow:

1. Draw a 2D profile or surface
2. Convert the sketch into a surface if needed
3. Extrude the geometry into 3D

I will work through the same example of custom geometry as the fusion turoial - working through the CAD of a simple rocking chair

Click to download Rocking chair design file

---

Draw inital geometry using sketches

• use coordinates to draw the dimensions of the first leg starting from 0,0

• refrencing the first leg use lines to create reference points in order to draw the remaining components to the correct dimensions

---

Create solid forms

Extruding Curves

Use:

• ExtrudeCrv

Process:

1. Select closed curve
2. Specify extrusion direction
3. Enter height

Options:

• Solid=Yes creates a closed solid body

• BothSides=Yes extrudes in both directions

Extruding Surfaces

Use:

• ExtrudeSrf

This is useful for:

• sheet bodies

• curved panels

• more advanced shapes

For the chair example I used Extrude to pull select sketches into solid forms

---

Using the Move Command

1. Select object
2. Type Move
3. Choose a base point
4. Choose direction or destination point

Tips:

• Use the viewport that best matches the movement direction:

• Top View → X/Y movement

• Front View → vertical movement

• Right View → depth movement

• After beginning the move, type the exact distance into the command line.

Example:

• Start moving object horizontally

• Type # you want

• Press Enter

• Click the object to move and use command “move”

• Click in the window with the best visiability for the direction you want to move the object. Once you start moving it in the correct direction, type the exact disctance into the left hand pannel.

• Once the object is in the correct location, group it with other elements to maintain its realtive location

---

Using the Gumball Tool

The Gumball is often faster than the Move command.

Features:

• Arrows move objects

• Arcs rotate objects

• Boxes scale objects

Tips:

• Drag arrows to constrain movement to one axis

• Hold Alt while dragging to create copies

Enable:

• Bottom toolbar → Gumball

---

Organizing Geometry

Grouping Objects

Once parts are correctly positioned:

• Select multiple objects

• Type Group

Benefits:

• Maintains relative positioning

• Easier selection

• Simplifies assemblies

To edit:

• Ungroup

---

Using Layers

Layers help organize complex models.

Typical layer structure:

• Construction

• Main Bodies

• Hardware

• Curves

• Reference Geometry

Useful features:

• hide layers

• lock layers

• color-code components

---

More ways to create geometry

Mirroring Geometry

Mirror is useful for symmetrical parts.

1. Select object
2. Type Mirror
3. Define mirror axis with two points

Tips:

• Use Osnap for precise symmetry

• Enable Copy=Yes to keep original geometry

Common uses:

• left/right components

• vehicle bodies

• furniture

• mechanical assemblies

Example

---

Creating Curves

Start with clean curves.

Useful commands:

• InterpCrv

• ControlPointCurve

• Arc

• Circle

InterpCrv

Creates curves that pass through selected points.

Good for:

• organic forms

• smooth transitions

Control Point Curve

Creates curves controlled by edit points.

Good for:

• industrial design

• controlled surfacing

---

Editing Curves

Use:

• PointsOn

• Move

• Scale1D

Tips:

• Fewer control points create smoother geometry

• Avoid overly complex curves

---

Creating Surfaces from Curves

Loft

Use Loft to create surfaces between curves.

Process:

1. Select profile curves in order

2. Adjust loft settings

3. Create surface

Good for:

• hulls

• handles

• ergonomic forms

---

Sweep

Use:

• Sweep1

• Sweep2

These create surfaces along rails.

Useful for:

• pipes

• trims

• structural members

Example

---

Revolve

Use Revolve for rotational geometry.

Examples:

• bottles

• cups

• wheels

• lathed parts

Process:

1. Draw profile

2. Select revolve axis

3. Rotate profile around axis

---

Joining Surfaces into Solids

Once surfaces are complete:

• use Join

Check if object becomes:

• Closed Polysurface

This means Rhino recognizes it as a solid body.

---

Boolean Operations

Useful for combining or cutting geometry.

BooleanUnion

Combines solids together.

BooleanDifference

Cuts one solid from another.

BooleanIntersection

Keeps overlapping geometry only.

Tips:

• Geometry must fully intersect

• Closed solids work best

---

Navigation and View Control

Basic Navigation

Rotate View

• Right mouse button drag

Pan

• Shift + right mouse button

Zoom

• Mouse wheel

---

View Modes

Useful display modes:

• Wireframe

• Shaded

• Rendered

• Ghosted

Switch modes from viewport dropdown.

---

Helpful Modeling Habits

• Build accurate curves first

• Save versions frequently

• Keep geometry organized

• Name important layers

• Use snaps consistently

• Check tolerances before fabrication

• Avoid unnecessary control points

• Build large forms first, details later

---

Intro to Grasshopper

Grasshopper is Rhino’s visual scripting environment.

Instead of drawing manually:

• nodes perform operations

• wires connect data flow

Grasshopper is useful for:

• parametric design

• repetitive geometry

• generative structures

• patterning

• optimization

Basic workflow:

1. Create parameters

2. Connect operations

3. Generate geometry dynamically

Changes automatically update the model.