Broccoli Ring Photogrammatry

This project is created as a course assignment at the California State University, Long Beach; instructed by Behnaz Farahi: DESN 551: Materials, Tools, and Techniques of Prototype.

For this project, I chose broccoli. It has interesting texture and branches, which reminds me of a small tree, Broccoli is an edible green plant in the cabbage family whose large flowering head, stalk, and small associated leaves are eaten as vegetables. Broccoli has large flower heads, usually dark green, arranged in a tree-like structure branching out from the thick stalk which is usually light green. Upright and branching with leathery leaves, broccoli bears dense green clusters of flower beds at the ends of the central axis and the branches call the floret.

The tree-shaped vegetable has a mixture of textures. the stem and stalk are crunchy whereas the florets are soft.

Supplies

Photography:

- Camera (I use iPhone Xs)

- Tripod - Ring Light

- Plain Backdrop

- Plastic bag

Softwares

- Lens Buddy

- Photoshop

- Metashape

- Meshmixer

I put up a small setup on my desk. I use plain paper as a backdrop which works pretty well for my project.

At first, I try to use two light sources to balance out the shadow but they only create a harsher shadow. I ended up with only one light source. I put a semitransparent plastic bag over the ring light to diffuse the light and create a softer shadow.

The camera is best to set on a tripod. It is best to take pictures of the same angle. I used the application "Lens Buddy" to take the picture. Lens Buddy lets you set the timer and automatically takes the pictures for you without you having to constantly touch the phone, running the risk of moving the camera. I set lens buddy to take 50 pictures with intervals of 5 seconds. 5 seconds is enough time for me to rotate the object. I rotate it 10-20 degrees at a time and ended up with 48 pictures.

Tips

• Use background with minimum noise, plain color background works best
• Matte object works best as a shiny object will reflect the light making it harder for you to capture the picture.

I personally think it helps photogrammetry software a lot to have clean and well-contrast pictures. I use photoshop for this process

For this process, I use Metashape.

• To import your pictures into the software, go to (workflow>Add photo).
• I chose to arrange the pictures consecutively. For some reason, I think it helps the software to generate your model better.
• To begin building your model you can go to (workflow>Align photos). The program will begin to look for a point of reference in each picture and generate a cloud base model, a "rough sketch" of your object
• To turn your cloud base model into a mesh to go (Workflow>Build Mesh). This will generate surfaces and 3d polygonal mesh
• After this you can export your model! Go to (Export> Export Model). I export my model in .obj file

From Metashape .obj file I imported the file into Meshmixer to clean up my models.

My model has a lot of issues since it was very detailed. There are points in which the model is less than 2mm thin, which means there will be a problem during the print.

To fix this, I increased the thickness of the model in the part that seems fragile. You can easily do this by clicking (Analysis > Inspector > Auto Repair all). This process fixed most parts of my model but there are some fragile parts that I have to manually fix

After I am satisfied with my broccoli model, I added the ring. In (Meshmix) you can find pre-made shapes in which you can add to your model.

I cut off the stalk part of my broccoli (Edit > Plane Cut) and insert the ring there!

I exported the file as .obj file.