Engineering Fundamentals3D ModelingProfessor Will Schleter

April, 2019 EF 151 Workshop

Goals for today● Overview of available design tools● Conceptual Design

vs Prototypingvs Detail Design

● Learning to learn, investing● Whirlwind tour of OnShape

● Parametric 3D Design○ Onshape.com○ Autodesk Fusion 360○ Autodesk Inventor○ Solidworks○ OpenSCAD (scripting)

● 3D Modeling○ Blender○ Sketchup○ 3D Builder (Windows)○ Autocad

3D Modeling● Browser based, no software installation, cloud file storage● Created by group that left Solidworks● Sharing and collaboration● Ease of use● Free educational license● Good online training● Similar terminology and methodology to other systems● Regular and frequent updates

Why Onshape?

● Get an educational account● Viewing● Sketching● Sketched Features

○ Extrude, Revolve, Sweep, Loft

● Combining Features○ New, Add, Remove, Intersect

● Placed Features○ Fillets, Chamfers, Shell, Draft, Rib, Patterns

● Multiple Parts and Assemblies● Exporting for 3D Printing

Onshape Basics https://cad.onshape.com

● Get excited about learning new things● Continue to learn - ask questions, practice, be aware● Teachers are guides● Suggested online resource:

○ Onshape Learning Center○ Self Paced○ Learning Pathway○ CAD Fundamentals

■ Minimal - Navigating, Sketching, Part Design■ Good info - Multi-parts, Assemblies■ Extra for certificate - Drawings

Invest in Yourself - Learn to learn

Frequently Used Keys and Mouse Commands● alt-C - command search● ctrl-? - Show all keyboard shortcuts● ctrl-z - Undo● delete - delete selected item(s)● space - clear selection● esc - back out of command● shift - suppress constraint inferences● left mouse click - select● right mouse click - context menu● selection box - drag right - enclosed,

drag left - crossing

● f - zoom to fit● z, shift-z - zoom out/in● n - view normal to● arrows - rotate view● wheel - zoom● right mouse drag - rotate view● ctrl-right mouse drag - pan view● p - toggle planes on/off

Sketching Details

● Test ideas with no dimensions,then re-edit to add sizing

● Avoid too much detail● Constraint inferences (hold shift to disable)● First dimension scales entire sketch● Use logical constraints where possible● Use blue handles to explore degrees of freedom● Use image as reference● Everything connected (shaded area)● Dimensioning (click in blank space to place text)● Mirror (Symmetry)

● Blue vs. Black - black is fully constrained● One sketch - multiple features or parts● Text (dimension to size)● Transform● Construction Geometry (Q)

Geometry

Modifiers

Dimensions

Constraints

OnShape Tidbits● Sketched Features: Extrude, Revolve, Sweep, Loft● Combining Features: New, Add, Remove, Intersect● Placed Features: Fillet, Chamfer, Shell, Hole, Patterns, Mirror● Part Operations: Boolean (Union, Subtract, Intersect), Split,

Transform● Face Operations: Move● Add-ons: Featurescript (Gears, Threads, Curved Text, …)● Assemblies - combinations of parts to show fit and motion● Variables - use to control dimensions on several features/parts

Feature TypesExtrude Revolve Shell

PatternHolesLoft

Fillet Chamfer Draft Sweep

Extrude/Intersect

2nd Sketch Extrude/Add

Extrude/Remove

Making Changes● Use meaningful names!● Double click is your friend● The feature list

○ Editing sketches(geometry, dimensions, constraints)

○ Editing features(thickness, extrusion type, pattern count)

○ Reordering features○ Rollback bar

● “Design Intent”● “Everything is related”

Feature

Sketch

Rollback Bar

● Size - 3D printing is slow - minimize size and volume

● Complexity - Very complex details won’t print well - try ideas out on a small object if in question.

● Orientation - Typically need a flat surface to build up from. Layer orientation might affect strength.

● Overhangs - 45° rule, Spanning

Design Considerations for 3D Printing● Material - Common materials are

PLA and ABS. ABS is not as brittle and slightly stronger.

● Supports - try to avoid or add as part of model

● Minimize material - thin walls, cutouts if possible, consider other methods

● Printability - consider making multiple simple parts and assembling

Example

NOTES● Thinner● Multiple Parts● Simplified● Stress Points● Print Orientation● Text

Suggestions and Common Issues

● Avoid surfaces - select faces, not edges● Avoid extra parts- make sure Merge Scope

is set correctly● Avoid too much detail● Features with errors - delete or fix● If fillets or chamfers don’t work, try a

smaller size and/or doing in several steps● Create cosmetic features last (fillets,

chamfers, threads, text)

Onshape - Export to STL (3D Printing)● Right click on Part Studio tab

or individual part in Parts List● Export● Use settings shown● Give it a meaningful name● STL file will be saved in

downloads folder of browser● Copy to USB drive to move to

printer

Part Studio TabPart List

Onshape - Export to DXF (Lasercutter, CNC Router)● Right click on any planar

surface● Export● Use settings shown● Give it a meaningful name● DXF file will be saved in

downloads folder of browser● Copy to USB drive to move to

printer

Planar Surface