3. Computer-Aided Design - Week 2


3.1. Assignments

Computer-Aided Design

  • Model a possible final project (raster, vector, 2D, 3D, render, animate, simulate, …)

  • Compress your images and videos

  • Post a description with your design files on your class page

3.2. CAD-Software

I tried following CAD-Software (I work under Linux so my choice was a bit limited):

  • Onshape (not in depth)

  • LibreCAD

  • FreeCAD

  • OpenSCAD

3.2.1. Onshape

I didn’t like Onshape because of the first quick-start video, which in the first tips for the software was advertisement for sharing the software and to use the mobile app, which scared me a bit and I didn’t continue.

I may try it later in a later point but I now like FreeCAD already.

3.2.2. OpenSCAD

I’ve designed before a little cover module for my keyboard. It’s a really interesting way to design I really like this programming-way :D

OpenSCAD Picture

3.2.3. Blender

Blender Picture

Already modeled with blender, but learned new many new things:

3.2.3.1. Findings

3.2.3.1.1. No Numpad
  • preferences -> input -> emulate numpad (1-0 are new numpad keys)

  • keymap ‘frame select’ -> change 3D select with ‘Numpad.’ to ‘.’ -> orbital change object

  • navigation -> zoom to mouse

3.2.3.1.2. Keymaps

-> mouse buttons AND shortcut depend on the window

  • Shift+Drag on window (border) -> new same extra window

  • t -> toggle toolbar

  • n -> numerical side-panel

  • g -> move (grab)

    • on top: info for the distance

    • in ‘g’->’y’->’1’->’Enter’ (arbitrary, also negative value)

  • numpad 1/3/7 -> front/right/top

    • with Ctrl opposite

  • s -> scale -> depends on the center of opject (close = big adjust, far = small/precise)

  • r -> rotate

  • Alt+g/r/s -> resets those settings -> !!ONLY OBJECT MODE!!!

  • ctrl+n -> new file

  • x/y/z -> use axes

  • shift+x/y/z -> move in the plane

  • Tab -> toggle between object and edit mode

  • c -> paint select (scroll for circle)

  • a -> select all, aa -> deselect all

  • l -> select object under it

  • e -> extrude

  • ‘origin to geometry’ -> sets the origin point

  • in the top icons -> change rotation point

3.2.3.1.2.1. Edit mode
  • 1,2,3 -> change between selection modes

  • when moving in edit mode -> topology of selected stuff changes but not origin point!!!

3.2.3.1.3. Modufier
  • Wrench-Icon -> add modifier

    • Subdivision surface <5! (else crash)

    • more surfaces

    • always from origin point

3.2.3.1.4. Notes
  • in move -> middle mouse uses axes

  • when inserting an object(so only after add), left bottom a bar is showing for settings

  • right mouse button on button -> assign shortcut

  • ‘Shade Smooth’

  • ‘Shade Auto Smooth’ -> smooth shades above a degree

  • middle click toolbar -> drag it

  • right-click -> cancle

  • atomatically creates .blend1 files (backup) when saving -> higher number == older

  • base-unit==mm

  • local view -> only show selected (top left indicator)

  • last object gets brightest orange

  • shift click selection modes -> select them

  • everything where you can type a number -> keyframe (animate)

3.2.4. LibreCAD

I liked working with it, was very intuitiv and easy to learn.

LibreCAD Picture

I documented here some findings i had:

Principles and Practices

3.2.5. FreeCAD

It was the first time for me using CAD-Software.

3.2.5.1. Findings

The Tutorial

3.2.5.1.1. Constrains
  • important to fully constrain -> unconstrained parts can lead to reconstruction errors on model regeneration

  • different workbenches for different design methods

  • white drawing tools, red constrain tools

  • new body -> creates a coordinate system, shown with ‘space’

  • new sketch -> klick on plane to draw on it

    • draw sketch and then apply constrains to it

    • drawing on the axes stays on the axes -> ‘constrained’ to it

    • auto-recognizes straight lines -> red line next to cursor

  • for constrains (eg. horizontal/vertical line), select stuff and use red icons to apply

  • dimension tool for setting length) -> constrains length

    • click on line to define dimension

    • if something is fully constrained, turns green

3.2.5.1.2. Variables
  • parametric approach -> enable dynamic adjustment

  • ‘{}’-Icon for variables

    • create variable for body with name VARNAME

    • select sketch again and select dimension to combine the variable with

    • double click and select ‘fx’-button -> use VarSet.VARNAME

    • also possible to use relateive size -> VarSet.VARNAME + 20mm

  • dimension with variable turns orange

  • create external Geometry -> project object contures for sketch

3.2.5.1.3. Assembly
  • create ‘assamble’ of an object with many sub objects and just combine with selecting faces/edges

3.2.5.1.4. Format
  • export as .3mf -> better meta data for continous production/verarbeitung

3.2.5.2. Tutorial Outcome

I followed above mentioned tutorial and build this in it:

Tutorial Clamp

Clamp STL

Also with the tutorial from Ferdi, I learn even more about FreeCAD and designing with CAD-Software:

Ferdi Lego

Lego STL

3.3. Image and Video Manipulations

For image manipulations I tried:

  • GIMP

  • Inkscape

  • Kdenlive (personally tested)

3.3.1. GIMP

GIMP Example)

3.3.1.1. Findings

  • CTRL-Shift-A -> deselect all

  • CTRL in path -> change bezier or connect

  • left bottom button -> show mask -> edit with brush etc.

3.3.1.1.1. GIF
  • name layers NAME (TIMEms) e.g.: layer_1(100ms)

3.3.2. Inkscape

Inkscape Example

3.3.2.1. Findings

  • set property/size to machince one

  • Ctrl in creating a shape -> snap

  • Crtl+Shift in creating an object -> snap + use startpoint as center

  • Tab ‘Align and Distibute’ -> align object relative to another

  • Node Tool -> change nodes to be used

  • Ctrl+d -> duplicate

  • Ctrl+- on selected objects -> remove from each other

  • Ctrl+G -> group objects

    • Import:

      • Embed -> copy in it

      • Link -> update if original updates

3.3.3. Increase smallness of images and videos

For changing videos and images sizes/format, I use ffmpeg and imagemagick. Currently I only needed the magick-command, e.g.:

magick INPUT.jpg -fuzz 30% -quality 0.5 -resize 1000 OUTPUT.jpg
#                                       ^^^^^^^^^^^^ resizes the width to this value and changes height accordingly
#                          ^^^^^^^^^^^^  compression quality
#                ^^^^^^^^^  sets the distance, for wich pixels are considered equal

3.4. First design files Final Project

First model of the left key made with FreeCAD:

KeyLeft STL

3.5. Learning Outcomes

  • I need a better documentation workflow (document as I go, directly in the right format)

  • CAD design principles (completely new to me)

  • Inkscape from scratch