Week 2 Computer Aided Design

Summary

This week I set out with great ambition to explore lots of different imaging software. In the end I spent most of my time learning Solidworks and was able with some assistance from Svavar my instructor to create an assembly that is representative of my final project. I also created several crude drawings of the project. My freehand skills are limited so the best fit for me are tools where I can easily access lines and shapes on a grid with a user interface that minimizes clicking around and easily accessible help/tips. I also learned that I need to start each week with more intensity and it goes by quick. This week I am going to plan everything Wednesday night and get started on the group assigment then have the first meeting Thursday night and get more done before the weekend so I'll progress a bit faster.

Assignments

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

Assessment Criteria

Learning Outcomes

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 project in 2D and 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

1.1 Plan for the week

In order to complete this task there are several steps that I need to take.

1. Break down my sketch into components that I can model either in 2D or 3D with actual measurements.

The components on first glance are

1. A Roller

2. Tracks

3. Supports that connect the roller and the track

4. Motor that will drive the roller back and forth

5. A controller that turns the device off an on

6. A model of a forearm for the device to run on

7. A mechanism that gives compression to the roller as it goes over the arm. I may leave this for later in spiral development.

I have no experience with CAD so my first step in the learning process is to evaluate three different software programs. Solidworks, Fusion360 (Autodesk) and FreeCad to see what fits my needs the best. After the review of this week's class I realize that there are about 77 different programs that I could work in this week. They are divided into about five different categories.

2D raster 15 programs

2D vector 10 programs

3D design sketching 9 programs

3D sculpting rendering and animation 7 programs

3D CAD 35 programs

I created an excel checklist to keep track of all the programs listed on the class schedule page.

There is still more on the list with game engines, simulation, AI and audio, video. I am going to leave those for last after I finish completing the others.

My rough plan will be as follows

Finish 2-3 2D raster images Friday

Finish 2-3 2D vector images Friday

Finish 2-3 3D design sketching images Saturday

Finish 2-3 3D sculpting rendering animation images Saturday

Spend the remainder of tiie working in 3D CAD exploring Solidworks, FreeCad and perhaps Fusion or Onshape

I am going to draw the roller portion of the Robophysio Elbow Roller to start with and maybe add the supports if I have time. The roller is basically a cylinder with some indentations and the supports are undefined but could be a rectangular prism or also some sort of cylinder that has wheels on the bottom that interact with the track. My original pencil sketch that I made during our prefab class shows the components. The track isn't very clear which I will fix in a digita drawing.

1.2 Learning

My very first task is to review Nadieh Bremer's documentation on CAD which was referenced in the class as a good example and see if my rough plan matches what she did.

She mentions an app called Tayasui sketches and I have and iPad and Apple pencil so I will look into this approach.

Her vector approach seems heavily programming based and not a fit for me. I am going to try Inkscape even though she does not like it.

Her framework for how she documents is good and I will aim to imitate that with a couple of additions.

1.3 2D Raster sketch images

So this was an interesting experience. Tayasui seems like a great program for people that are reasonably good at drawing, I am not none of them. This picture is an example.

Here is another example of a crude drawing I made using the Apple pencil

I think I am better suited for a simple program where I can select shapes, pick the dimensions I want and go from there.

Bring out the GIMP... I am starting with GIMP as well and going through the beginners tutorial called GIMP Quickies. It is not very detailed or helpful.

Well this one is strange I managed to import an image of what looks similar to my roller but it refuses to let me draw on it using pencil or paint brush tools.

Svavar sent me this instructional video

I pick the selection tool and press the mouse button and nothing happens. And I think the problem is that I didn't know how to use layers. So I am going to try again. Here is the result. It is not very good. I am able to import an image and paint on it but my overall impression of GIMP is that you do a lot of extra clicking for no good reason. For example you cannot just right click or double click to change colors and after I did a selection and bucket filled it with paint then it was just stuck there and I couldn't get rid of it. I am sure this is all learning curve but in the the interest of time management I am not spending much more time with this software.

I may just skip this one and move on to Inkscape and Solidworks.

1.4 2D Vector sketch images

Having read Johannes documentation this week he was not very impressed with Inkscape I decided to skip it and look at Coreldraw and Sketchpad instead.

I immediately like the user interface on Sketchpad and I make a quick drawing. It's pretty ugly but the menu based system is pretty easy to use and you can get a grid to draw on. I think this could be a go to for simple shape based sketches that then could be planned into Solidworks.

After discussing with Svavar I decided to give Inkscape another try. It is not terrible but not good. Why would you have a 5 step process just to create an arrow in a picture. I did import my final assembly in Solidworks and did a trace bitmap of it. I was also going to add arrows to indicate the parts of the assembly but drawing an arrow is a five step process and I didn't like to look of the one I produced so I left this for now.

1.5 3D 3D Sculpting Rendering Animation

I ran out of time to explore this and will do so in the following weeks. I have downloaded Blender and it would be cool to have an animation of my project that shows it rolling up and down a forearm.

1.6 3D CAD

Solidworks

This is what I am most interested in so I am skipping ahead to this and starting out with a tutorial. I start by viewing this Solidworks for beginners in 13 minutes on the basics and then I want to find one that shows how to create a 3D Barrel shape with supports that I can work along to. This approach worked well with the VCARVE video for the ShopBot so hopefully I can replicate this and have more success than with Tayasui or GIMP.

5 Minutes into the video they have gone through the basics and I am going to try making a 2D sketch in Solidworks. I pick part and start working through this. They recommend always starting in the top plane so that is what I'll do.

I made a very simple drawing of some rectangles connected to each other that could represent the view of the roller from the top down.

Not very impressive so far but I am a total beginner. It seems Solidworks has a reasonable enough interface that I could learn it and it looks like there are lots of tutorials available. I'll take a quick peek at other programs but there must be some reason this is so heavily used in industry.

Having experimented a bit with the images above I don't think I am quite understanding what I am doing and how to do it On to the official Solidworks tutorials next.
Solidworks tutorial for parts

So make a simple sketch, extrude it to 3D and then use cuts, I think I have been making my sketches to complex.

Great success! I managed to make a simple box with a hole through it and starting to understand how to toggle between the different views.

Now I need to start with creating a part that looks more like my roller and add a proper support part that hopefully I can just mirror and then assemble into a model. If I can achieve that I will consider the Solidworks mission complete for this week.

I managed to create a roller using the extruded boss feature. I selected the right plane and sketched a circle. That I could then extrude to a tube shape. I then used the rectangle to make extruded cut holes through the roller shape. This is not necessarily what the final design will look like but it was fun to try. I need to figure out how to create relations/constraints so that they are of equal size and equidistant apart. I then went to th right plane again and drew another circle that I then extruded to a cut which made this into a tube. I also managed to edit the appearance using the appearance tab and make it yellow, similar to the manual model it will replace.

Now onto creating and actual support looking shape and then see if I can assemble them together. To make things interesting I created a hexagon support with hole through it.

I should be able to assemble this into a simple representation. Keyword being "should" this is not quite as easy as I though it would be as you can see in the image below.

I need to go through an assembly tutorial to get this right.

First attempt at an assembly is not a great success, need to find a clearer tutorial.

I reviewed this tutorial on you tube and managed to get one end of the tube to mate with the hexagon support. On the other side it failed.

This is not getting them to mate properly, need to look for additional tutorials on this subject or perhaps abandon it for now and ask for help. I suspect I need to revisit the dimensions of the tube and the hole on the hexagon support in order to get the mating function to work.

I sought some help from Svavar with the assembly process and he showed me some valuable steps. You have to carefully pick the surfaces that you are mating and you also have to mate multiple surfaces to get the components to align properly. You also need to fix the feature to a plane so that you can get the components to align properly. After multiple tries I was able to get this hero image with an assembly that represents my final project.

2. Compress your images and videos

I think I have found a good solution here with XnVconvert and look forward to trying it out with videos as well. The process is simple, open the program, click add files and add the PNG files you want to compress. Click output and select the type of files you want and the image quality. I use the lowest image quality to minimize file size. For my design files I simply used winzip to compress them into a folder by right clicking and selecting that option in windows.

3. Post a description with your design files on your class page

Here is a Link to my Solidworks files.

Learning outcomes

I learned about a variety of 2D and 3D computer aided design programs. I also learned about my own preferences and limitations. I prefer to use computer aided shapes, lines, images and grids rather than to do freehand imaging. I only explored Solidworks rather than evaluating all the 3D Cad programs as particularly in the beginning my progress was very slow and I needed to repeat steps and tutorials a lot. Lastly I learned a valuable time management lesson to start the week with more intensity as it is beneficial to be able to step away from what you are doing, process it and then come back and make additional progress rather than making each learning session too long.