Week 2: Computer-Aided Design

Assignment

• Model (raster, vector, 2D, 3D, render, animate, simulate, ...) a possible final project, compress your images and videos, and post a description with your design files on your class page

Learning Outcome

• Evaluate and select 2D and 3D software
• Demonstrate and describe processes used in modelling with 2D and 3D softwares
• Demonstrate image and video compression

Have you answered these questions?

• Modelled experimental objects/part of a possible final project in 2D and/or 3D software
• Shown how you did it with words/images/screenshots
• Documented how you compressed your image and video files
• Included your original design files

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Research & Planning

I am looking over the options in the Computer Design portion of the schedule to determine what software I would like to try.

For 2D design I am already familiar with Photoshop and GIMP so I am going to look at Inkscape as one of my 2D programs.

For 3D design I have been working in Fusion 360 and I am very much a novice. I'm still going to experiment with Sketchup and Blender.

I signed up for SolidWorks and the subscription has processed. Even though I have a MacBook, I chose the desktop version since it seems to have more features. I have a Windows computer that I can run it on.

My time management for week 1 assignments was not very efficient. This week I gave Claude AI the requirements and asked it to assist in scheduling. I have a six hour block of time this morning and here was the result.

I have started my timer on my phone so I will not lose track of time.*

Blender

Angela Horstman gave me a quick, but thorough tutorial on Blender the other day that included shortcuts, basic concepts and animation.
Shortcuts:

Key	Action
S	Scale object
R	Rotate object
G	Grab/Move object
E	Extrude selected face/edge
I	Inset selected face
A	Select All
X	Delete selected object
Tab	Toggle between Object Mode and Edit Mode
Ctrl + R	Loop Cut (add edge loops)
Shift + A	Add new object (mesh, light, etc.)
Shift + D	Duplicate selected object

Angela taught me how to make animation. Below is a screenshot from that animation:

Here is the actual animation:

Time to continue working on Blender...

5 hours later...

Since Angela's tutorial was so fresh in my memory I thought I would tackle Blender and move on to another software. I was mistaken when I thought that I would master it quickly. While Angela is an excellent teacher and I understood everything she presented, when I tried to do it myself I couldn't recall all of the commands. So I went over to YouTube to find a quick tutorial on Blender. One of the main issues with the tutorials is no one zooms into the interface so you can see what they are clicking without replaying a few times. That slowed my progress a lot.

I believe the two tutorials below would have been sufficient, but I couldn't deal with the resolution from my laptop.
How to 3D Model Using Blender
How to Design for 3D Printing in Blender - Beginner Tutorial

I finally quit being stubborn and hooked up a monitor and worked through this tutorial - The World's Easiest Blender Tutorial For Beginners It was informative and very entertaining as a bonus.

I modeled this sweet ride after the one in the tutorial:

I have a better understanding on how the software works since I walked through that tutorial. On my agenda is to create another object without instruction to see how much I retain. That's for another day.

(I just realized while reviewing this page I did not create any screenshots while I was creating the car. I'll go over the tutorial again either today or tomorrow and add screenshots.)

Inkscape - 2d Vector

I'm changing my tactics on this one. Instead of finding a YouTube tutorial on how to use Inkscape, Claude AI is going to be my tutor.

Prompt: quick tutorial on inkscape for fab academy student creating cnc machine

With Claude AI instructions, I started by setting up the document in Inkscape for CNC work. In File, Document Properties, I set the page size to 100 x 100 mm and made sure the display units were set to mm. The grid was already configured to 1mm spacing by default.

When I drew my first shape, something was off. I asked Claude how to check the dimensions and it told me to look at the W and H fields in the top toolbar. The numbers showing were 194 x 148. Ok, now what? I took some screenshots and shared them with Claude. He noticed that my rulers were showing values like -2500 and -5000.

Claude very patiently explained that the object was in "negative coordinate space" which means it was not even close to the actual page. I thought I was on the page since I saw the grid. According to Claude, the page sits near coordinate zero and I had somehow drawn everything way outside of it. To fix this:

• Cmd+A to select everything
• Press 5 to zoom to fit the page
• Delete the oversized object
• Now I could see the white canvas

Once I "found" the canvas I was able to draw the rectangle to the size I wanted.

I also ran into an issue where my rectangle had rounded corners when I wanted square ones. I originally drew square ones and didn't know how it changed. Claude pointed me to the Rx and Ry fields in the top toolbar which control corner radius. Setting both to 0 gave me sharp corners.

Such minor issues, but since I am learning this software I didn't understand what was happening.

I asked Claude for instructions for a simple drawing. He suggested an L-bracket.

For the bracket, Claude gave me coordinates to follow using the Bezier pen tool (B). I clicked the following points:

• (10, 10)
• (10, 50)
• (30, 50)
• (30, 30)
• (50, 30)
• (50, 10)
• (10, 10) to close the shape

The bracket had a color fill of red. I didn't want any fill:

• Object, Fill and Stroke
• Fill tab, click X to remove fill
• Stroke paint tab, click solid color box to add outline
• Stroke style tab to set width

For the mounting holes:

• Ellipse tool with Cmd held down for a circle
• Object, Transform to set size to 5mm
• Placed first hole at (20, 40)
• Cmd+D to duplicate
• Moved copy to (40, 20)

Before cutting the holes I asked Claude for a sketch to compare. He provided and it matched so I continued. To cut the holes:

• Cmd+A - Select everything
• Path, Object to Path
• Path, Difference

I wanted to verify the holes were cut, Claude suggested adding a temporary fill to the bracket. The hole areas filled in, in addition to the bracket which meant the cut didn't work. Claude asked to confirm the objects were paths and instructed me to look at the status bar at the bottom of the screen when I selected each object. They showed Path 4 and Path 6, so that wasn't the issue.

Claude suggested cutting one hole at a time:

• Select the bracket and one circle
• Path, Difference
• Select the result and the remaining circle
• Path, Difference again

That worked.

This is an important one to remember. If Path, Difference isn't working with multiple objects, cut them one at a time instead.

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Cameo 5

After creating my bracket in Inkscape I wanted to test cut it on my Cameo 5 using cardstock. I saved the file as SVG and imported it into Silhouette Studio. The file came in fine and I could see the bracket with the holes.

In Page Setup there was a gray line running through my workspace. Claude explained that it was showing the edge of my paper size. The mat was set to 12x12, but the paper was showing as a smaller size like 8 1/2 x 11. The white area is the paper and the red border is the cutting area of the mat. As long as my design stays in the white area it will cut.

My first cut didn't go through the 80lb cardstock. Claude suggested adjusting the settings:

• Blade depth: go deeper, around 3-4 for heavy cardstock
• Force/Pressure: increase it
• Speed: slow it down
• Passes: set it to cut twice instead of once

To check if it cut through without removing the material from the mat, Claude suggested gently lifting a corner or one of the small circles with a weeding tool. If it lifts cleanly it worked. I couldn't lift it soooo....

My next attempt cut some parts of the cardstock deeper than others. Claude said this could be caused by:

• Mat not flat or has buildup from old adhesive
• Dull or chipped blade
• Material not stuck down evenly
• Rollers not gripping evenly
• Material thickness varies
• Blade housing loose

I wondered if my blade was worn out, but I had only cut a few times. Claude said a blade should last hundreds of cuts. If it's struggling already it could be defective, not seated correctly, the wrong blade type, or the blade depth set too high which can damage the tip by hitting the mat. I will try another type of material.

Update: My blade tip was the issue. I bought a new one and when I made a comparison the old blade's tip was broken off enough to cause issues.

I will admit my experiment with Claude as my tutor, while not perfect, it led to a more efficient day.

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Gimp (2d raster)

Dr. Taylor reviewed my work and recommended I work through GIMP since it is a 2d raster program in comparison to Inkscape which is 2d vector.

I installed GIMP on macOS by downloading it from gimp.org.

GIMP interface

I wanted to replicate the 2d vector image I created in Inkscape for comparison with GIMP.

I started by creating a new 100mm × 100mm image at 300 ppi via File → New.

Create a New Image dialog

So...why did my 100mm change to 99.99mm? Claude?

GIMP stores everything internally as pixels. When converting 100mm at 300 ppi:

• 100mm × (300 pixels ÷ 25.4mm) = 1181.102 pixels
• Pixels must be whole numbers, so GIMP rounds to 1181 pixels
• Converting back: 1181 × (25.4 ÷ 300) = 99.99mm

This is a floating-point rounding artifact — the image is functionally 100mm.

I was stuck at this point. What are my next steps to duplicate the vector drawing? Of course I asked AI.

Setting Up the Grid

To work precisely in a raster environment configure a visible grid with snapping:

1. View → Show Grid — display the grid overlay
2. View → Snap to Grid — selections and tools snap to grid lines
3. Image → Configure Grid — customize grid settings:
   • Spacing: 10mm (horizontal and vertical)
   • Line style: Solid

Configure Image Grid dialog

Drawing Rectangles

First Rectangle: 20mm × 40mm

Using the Rectangle Select tool, draw a selection snapped to the grid (10mm to 50mm horizontally, 10mm to 30mm vertically), then fill it with black using the Bucket Fill tool.

A 20×40mm black rectangle

Second Rectangle: 40mm × 20mm

Draw a second rectangle (40mm tall × 20mm wide) overlapping the first to form an L-shape.

A 40×20mm black rectangle overlapping the first

Creating Holes with Ellipse Select

To create circular holes, use the Ellipse Select tool and Edit → Clear to delete pixels within the selection.

Hole 1

• Tool: Ellipse Select
• Position: 20mm, 40mm
• Size: 5mm × 5mm
• Action: Edit → Clear

First 5mm circular hole

Hole 2

• Tool: Ellipse Select
• Position: 40mm, 20mm
• Size: 5mm × 5mm
• Action: Edit → Clear

Second 5mm circular hole

Okay, my work is done. This one looks just like my 2d vector. Beautiful! Now what? Zoom in? Sure.

800% zoom in GIMP.

Interesting....

800% zoom in Inkscape

So what did I learn from this?

Definitely a 2d raster program does not work like a 2d vector program — I easily created shapes in Inkscape with coordinates, but in the raster program I had to make a selection and then either fill or clear it.

Without the grid and "snap to grid" settings I would not have been able to accurately recreate the image from the 2d vector program.

The big difference is when you zoom in and compare the two files. The 2d vector image doesn’t pixelate, whereas the 2d raster does.

Ok. Let's move on.

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My next task is to understand the workflow of Fusion 360. I asked Claude to step me through a simple process. Below is the result, with Claude creating the documentation from our lesson.

Fusion 360 CNC Workflow

Overview

The workflow consists of five main phases:

1. Design — Create the 3D model
2. Manufacturing Setup — Define stock and work coordinates
3. Toolpath Creation — Tell Fusion how to cut
4. Simulation — Verify the cut virtually
5. Post-Processing — Generate G-code for your machine

Part 1: Design Workspace

Creating the Base Plate

1. Open Fusion 360 and select Part Design
2. Save your file (File > Save) — Fusion saves to the cloud by default
3. Click Create Sketch and select the XY plane
4. Use Rectangle > Center Rectangle (or press R)
5. Click the origin point and drag to create a rectangle
6. Set dimensions using the D key:
7. Width: 100mm
8. Height: 60mm
9. Click Finish Sketch
10. Press E for Extrude, select the rectangle, set distance to 10mm, click OK

Adding a Pocket

1. Click the top face of your plate
2. Click Create Sketch
3. Draw another Center Rectangle
4. If the rectangle isn't centered, use dimensions (D key) to position it:
5. 15mm from left edge
6. 10mm from bottom edge
7. Size: 70mm x 40mm
8. Click Finish Sketch
9. Press E for Extrude
10. Set distance to -5mm (negative to cut into the part)
11. Click OK

Part 2: Manufacturing Workspace

Creating a Setup

1. Switch to Manufacture workspace (dropdown in top-left)
2. Click Setup > New Setup
3. On the Setup tab:
4. Operation Type: Milling
5. Origin: Stock box point
6. Select the top-left corner of the stock
7. On the Stock tab:
8. Mode: Relative size box
9. Set all offset values to 0mm
10. Click OK

The yellow transparent box shows the stock material. The XYZ axes show the work coordinate origin at the top-left corner.

Part 3: Creating Toolpaths

2D Pocket Operation

1. Click 2D > 2D Pocket
2. Click the Tool field to open the tool library
3. Select a flat end mill (1/4" or ~6mm diameter)

For this exercise, any flat end mill with flute length greater than 5mm (0.2") will work.

1. Click the Geometry tab
2. Select the bottom face of the pocket

Configuring Passes

1. Click the Passes tab

1. Check Multiple Depths to enable stepdown control

Maximum Roughing Stepdown controls how deep each pass cuts. 0.635mm is conservative and good for a Dremel-type spindle.

1. Click OK to generate the toolpath

Blue lines show cutting moves. Yellow/green lines show plunge and rapid moves. The cylinder represents the tool.

Part 4: Simulation

1. Right-click on 2D Pocket1 in the browser
2. Select Simulate
3. Click Play to watch the virtual cut

What to Look For

Good Signs	Warning Signs
Pocket cuts cleanly	Red areas (gouging)
Tool stays in bounds	Orange areas (leftover material)
No collisions	Tool crashing through walls

Note: Small triangular bits in corners are normal — round tools can't cut sharp inside corners.

Part 5: Post-Processing

1. Right-click on 2D Pocket1
2. Select Post Process

Key Fields

Field	Description	Suggestion
Post	Post-processor for your machine	GRBL for most DIY CNC
File name	Name of your G-code file	pocket_practice
Comment	Optional note	Fab Academy CNC test
Output folder	Save location	Default is fine
NC extension	File extension	.nc is standard

1. Click Post to generate the G-code file

Quick Reference: Unit Conversions

mm	inches
5mm	0.2"
6mm	0.24"
6.35mm	0.25" (1/4")
25.4mm	1"

Key Shortcuts

Shortcut	Action
S	Search commands
R	Rectangle
D	Dimension
E	Extrude

Lessons Learned

• Center on origin: Drawing shapes centered on the origin makes alignment easier
• Negative extrude: Use negative values to cut into material
• Multiple Depths: Enable this to control stepdown for safer cuts
• Simulate first: Always simulate before generating G-code to catch errors
• Corner radii: Round tools leave rounded inside corners — this is normal

Output

The final .nc file contains G-code instructions that tell your CNC machine:

• Where to move (X, Y, Z coordinates)
• How fast to move (feed rates)
• When to cut and when to rapid move
• Spindle speed

This file can be loaded into any GRBL-compatible CNC controller.

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That was a great exercise and I have a better understanding of the workflow. Now I want to use Claude to assist with modifying a mount for my final project. I have the files from the original designer and want to modify it using a flexible shaft as opposed to the Dremel after questioning Claude - Here is the link to our conversation.

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Claude generated documentation

Designing a Flex Shaft Mount in Fusion 360

This documents the first attempt at designing a custom part in Fusion 360 with the assistance of Claude AI — a V-block mount for a Dremel flexible shaft handpiece to be used on a DIY CNC machine.

Project Goal

Design a mount that holds the Dremel 4000 flexible shaft handpiece on the Z-axis of a DIY CNC router, as an alternative to mounting the full Dremel body.

Why the Flexible Shaft?

Advantages:

• Less weight on the Z-axis gantry
• Reduced vibration potential
• Smaller form factor

Concerns:

• Few online examples of flex shafts used as CNC spindles
• Potential runout (wobble) issues
• The handpiece is tapered, not cylindrical — harder to clamp

Decision: Proceed with flex shaft design, with the Dremel 4000 body (43mm diameter) as a backup plan.

The Handpiece Challenge

The flex shaft handpiece is tapered along its entire length — there's no cylindrical section to clamp.

Measurements taken with calipers:

• Diameter at collar (near collet): 15.65mm
• Diameter 30mm lower: 23.28mm
• Taper: 7.63mm increase over 30mm length

Solution: Design a V-block mount instead of a circular clamp. V-blocks self-center on round or tapered objects.

V-Block Concept

Image generated by Claude AI

A V-block works by:

• Cradling the round/tapered object in a 90° groove
• Using a top clamp to press down and secure it
• Self-centering regardless of exact diameter

Fusion 360 Workflow

Step 1: Create the Base Sketch

1. New Design > Part Design
2. Create Sketch on XY plane
3. Draw a Center Rectangle (important: center on origin, not corner)
4. Dimensions: 40mm x 30mm

Lesson learned: Always use Center Rectangle when you want the part centered on the origin. This makes symmetry easier later.

Step 2: Draw the V-Groove

1. Draw a vertical line from the midpoint of the top edge, 10mm down
2. Draw two angled lines from the bottom of that line to the top edge
3. Delete the vertical construction line
4. Constrain the angle between the V lines to 90°

What didn't work:

• First attempt resulted in an asymmetric V (one side 7mm, other 3.5mm)
• Mirror constraint wouldn't select the Y-axis as the mirror line
• Symmetric constraint also had selection issues

What worked:

• Using the Equal constraint on both angled lines
• Setting explicit dimensions from each V endpoint to the center axis (10mm each side)
• Dimensioning the V depth (10mm from top edge)

Key insight: Blue lines in a sketch mean they're under-constrained (can still move). Black lines mean fully constrained. For simple parts, slightly under-constrained sketches can still work.

Step 3: Extrude the Base

1. Finish Sketch
2. Press E for Extrude
3. Select the solid region (outside the V)
4. Distance: 40mm

Step 4: Add Bolt Holes for Top Clamp

1. Create Sketch on the flat top surface (either side of V)
2. Draw a 4mm diameter circle (for M3 bolts to pass through)
3. Position it: 5mm from V edge, 20mm from front/back
4. Repeat on the other side of the V

Lesson learned: Both flat surfaces beside the V are coplanar (same height), so one sketch covers both sides. You don't need a separate sketch for each surface.

What didn't work: - Copy/paste for the second circle — couldn't see the pasted circle - Mirror tool — couldn't select the axis

What worked: - Simply drawing a second circle manually with the same dimensions

Step 5: Cut the Bolt Holes

1. Finish Sketch
2. Press E for Extrude
3. Select both circles
4. Set distance to -40mm (negative = cut) or use "All" extent
5. Operation: Cut

Investigating the Z-Axis Mounting

Before adding mounting holes, Claude examined the existing CNC design to understand how parts attach.

Findings: - The Dremel holder and Z-carriage are one integrated piece - The carriage has a 16mm x 16mm bolt pattern (4 small holes) - Two large holes for smooth rods - One center hole for lead screw nut

Challenge: Can't simply bolt an adapter onto the existing carriage — the Dremel clamp section is in the way.

Options identified:

1. Design a completely new Z-carriage with V-block integrated
2. Design an adapter plate (complex due to interference)
3. Modify the existing carriage design

Decision: Pause here and revisit mounting strategy later.

Current Status

Completed:

• V-block base with 90° groove
• Two through-holes for top clamp bolts
• Understanding of existing Z-carriage design

Still needed:

• Mounting hole pattern for Z-axis attachment
• Top clamp piece design
• Decision on integration approach

Key Lessons Learned

Sketching

• Use Center Rectangle to keep parts centered on origin
• Constraints (Equal, Coincident, Dimension) are how you lock geometry in place
• Blue = under-constrained, Black = fully constrained
• When Mirror/Symmetric won't work, manual dimensioning achieves the same result

Design Process

• Measure real parts with calipers before designing
• Check existing designs to understand mounting patterns
• Consider how parts integrate before finalizing dimensions

Fusion 360 Navigation

• S = Search for any command
• R = Rectangle
• L = Line
• C = Circle
• D = Dimension
• E = Extrude
• Right-click > Isolate = View single component
• Inspect > Measure = Measure distances and hole patterns

Next Steps

1. Decide on mounting approach (new carriage vs. adapter)
2. Design top clamp piece
3. Add mounting holes matching Z-carriage pattern
4. Test fit with actual flex shaft handpiece
5. 3D print prototype

Reference: Flex Shaft Handpiece Dimensions

Location	Diameter
At collar (near collet)	15.65mm
30mm below collar	23.28mm

V-block designed to clamp at the collar area where diameter is smallest, closest to the cutting tool for maximum rigidity.

Compression

I have been compressing photos for web documentation using Photoshop's Export function. I usually choose between WebP or JPG. I confirm the size before I upload and they are usually less than a 500KB. I did have one slip in on me around 2MB (my sketch of the final project) and quickly fixed it before I was scolded.

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Export Process

1. Open image in Photoshop
2. File → Export → Export As
3. Choose format from dropdown:
4. WebP — Best compression, smaller files
5. JPG — Universal compatibility

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Recommended Settings

WebP

Setting	Value
Quality	70-80%
Preset	Photo

JPG

Setting	Value
Quality	60-80%
Embed Color Profile	Off (for web)

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Quick Tips

• Resize first — Scale down large images before export (800-1200px width typical for documentation)
• Preview file size — Check the estimated size in the export dialog before saving
• Batch processing — Use File → Scripts → Image Processor for multiple files

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When to Use Each Format

Format	Best For
WebP	Documentation sites, modern browsers, smallest file size
JPG	Maximum compatibility, sharing with others, legacy systems

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Files

• V-block design: flex_shaft_mount_v1.f3d
• Reference CNC design: cnc_v44.f3d
• gcode: pocket_practice.nc
• Blender car: car.blend
• Inkscape L-bracket: L-bracket.svg
• GIMP L-bracket: L-bracket.xcf

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*This idea did not work. The alarm kept going off and I just kept hitting repeat for another hour.