Week 2, CAD Design

Objectives

: Model objects of possible final project with 2D and 3D software; Show you did it with words/images/screenshots; Document how you compressed images and video; Include original design files

2D Software

I evalulated Adobe Illustrator for my 2D CAD software. Since it was Groundhog Day this week, I used that as inpiration to draw a ground hog. I used a mix of line and pen tools to create a path that represented the shape of the groundhog.

Drawing

First I downloaded a clip art picture of a groundhog. It was a black and white graphic that would be easy to trace. Then I inserted a new layer so I could trace it without it messing with the original image. I used a combination of the pen tool to create the curved sections and the line tool for the straight sections of the art to stitch together an approximation of the groundhog.

Adobe Illustrator sketch of groundhog. Note the red lines show the as-sketched shape to compare to the orginal art in the background.

Tracing

Another option to get the shape of the groundhog is to trace the image. I made a copy of the original art and used the "Image Trace" command under the Window section on the menu bar. I updated the settings and I could see the software generating the paths based on the black and white borders of the art.

This traced the shape much more closely, but I did not use this art going forward.

Adobe Illustrator trace of the original artwork. Note that it capture the image far more accurately.

Going Further

Taking this a step further, I exported this CAD as a dxf and then brought it into SolidWork. From there I was able to scale the art and extrude it to make a cookie cutter in the shape of the groundhog.

Groundhog CAD — Bringing Illustrator art into SolidWorks to create 3D geometry

Groundhog AI File

DXF File of the shape

STEP File of the Cookie Cutter

3D Software

I evaluated two different 3D CAD software packages, SolidWorks and nTopology.

SolidWorks

I have worked with SolidWorks for a couple of decades and have a good understanding of how it can be used. I was able to start modelling a version of my photography project with SolidWorks by using a mix of surface and solid modelling techniques to make a virtual schematic. I was able to use layout sketches to define the initial geometry of the flare reducer and combined that with downloaded models of XIAO boards and LEDs to see how the whole project might come together.

Step 1

The first step was to create the lens hood. I started by creating layout sketches of the part that I measured directly from the part. Then I did a 'Revolve Surface' feature to create the ring of the hood.

Step 2

Then I thickened the surface to create a fully solid model. Then I added a plane for the ring light LEDs and drew ring and did normal extrude feature to rough in the shape.

Step 3

Next I extended the lens hood with a new body which will be where I will later inject light into the product. This was a regular extruded solid. Then I created a backboard for the ringlight LEDs using a simple revolve feature.

Step 4

Finally, I added a ring around the lens hood for the LEDs to attach to that will pint down into the lens hood. This was created using a simple revolve feature as well. I added a slot at the top for the wires to come out of the ring and then did some filleting througout the model to make it look better and to print with better quality.

Final model of the exploration of what my final project could look like.

STEP File of the completed Part

nTopology

I had never worked with nTop before, but had familiarity with its capabilities, so was excited to give it a try. I worked through a few tutorials about how the modelling environment works, how to manipulate and export CAD bodies and how to create lattice structures out of CAD bodies.

An example of how I used this software was to make a new type of orchid pot. I modelled a simple 3 inch planter in SolidWorks and split it into 4 different bodies. I then brought the model into nTop and turned it into an implicit body. Then I used the lattice tools to make gyroid cells for the bottom of the pot for water drainage and on the side of the pot for air exchange. I then boolean added the parts back together into a continuous pot shape, meshed it and exported as an .stl file for 3D printing.

SolidWorks File

First I started by creating the pot in SolidWorks. I took measurements from an existing 3inch pot that I bought on Amazon and created it with some surfaces in SolidWorks. Then I split the model into 4 different volumes. I did this as I wanted a lot of drainage in the bottom of the pot and wanted great air flow on the side of the pot. However I wanted to keep the upper and lower rings solid to keep some structural integrity.

3 inch pot modelled in SolidWorks and split into 4 different zones.

STEP file of the pot

nTop

Then I did the work in nTop to make the sides and bottom into lattices.

Import and Explicit Bodies

The first step was to import the step file and convert to explicit bodies. Explicit bodies is the language of nTop and allows additional functions to be carried out on them.

nTop window showing the pot being imported and each body being converted to an explicit body

Lattice

Then I created the lattice structure for the pot. I started by creating a periodic lattice that was big enough to intersect with the walls of the pot. I adjsted the dimensions until I got something that looked good for a pot. Then I did a boolean intersection function with the side and the bottom of the pot to get a nice lattice structure in just those areas.

Recombine and Mesh

Then I put the pot back together. I did a boolean union of the solid upper and lower ring and the lattice center and lower parts of the pot. This gave me a singular implicit body with the nice cutouts. In order to create a solid body, I had to mesh the new implicit body. I used the remesh tool to create a meshed body.

Export

Once the body was remeshed it could then be exported as a solid. I used the 'export mesh' tool to save the file as a .stl file that could then be brought into a 3D slicer for printing.

STL File of the finsihed pot

Image Compression

I used a couple of techniques for image compression

Transfer from WhatsApp

I send most of the pics of my projects from my phone through WhatsApp to transfer the pics quickly. When I save jpg files from web app, it automatically brings the file size down to a few hundred kilobytes, which is totally managable.

Paint Resizing

I also use MS Pain to resize images. The "Resize and Skew" tool allows for fast downsizing of images to suitable size. The default resolution is 800 x 800 pixels.

Compression — Resizing an image with MS Paint

Lightroom Export

I also use Adobe Lightrooom to resize photos. Full size images are brought into the catalog and the export tool allows for choosing a maximum pixel width or file size. This way, I can manipulate full sized photos without the heaviness of the original file