HW2b: Using Cartesian Coordinates for Views and Perspectives

What is the difference between a technical drawing, and traditional art?

Ans: Precise communication 

Each line has a specific length, orientation, and position relative to the other lines in the drawing.

AutoCAD and other drafting programs use Cartesian coordinates (x, y, z) to define endpoints of lines and centers of shapes.

HW #2:
Using excel scatter plots:

Insert→Charts→Scatter→Scatter with straight lines and markers


Create the following drafting objects in excel using a table of Cartesian (x,y) coordinates.


1.  Create a simple crane similar to the one shown below using a table of (x,y) endpoints, and a scatter graph in excel.

For dimensions of actual cranes, see:
http://www.bigge.com/crane-charts/#TC

Just click on one of the cranes, and get the pdf.  You do NOT need to reproduce an actual crane, just glance through them to get the main idea, and then sketch out your own design of a simple crane.

2. Create three representations of one bike.
one with units of inches, 

one with units of feet, 

one with units of cm.

One of the things you will need to get used to is switching between different unit systems and scale sizes.  Use the "CONVERT" function in excel.  

   
Can you figure out the equation for the tires?




3. Create a 3D pyramid and tent using a 3D surface graph.

Create the top and side views of pg 57 in your book on Excel:

Use the below dimensions:

Old 1201 Excel Basics Notes:

Review
Housekeeping:
Double click on a sheet name, and rename it to better organize your working area:
Here, I have renamed "Sheet 2" to "Cheetah", and "Sheet 3" to "Mousetrap Car"

Use the (+) to add more sheets.

Get in the habit of using multiple sheets for a project to better organize your work.

#1 Set up your table

Use big bold font for headings

Add borders to cells, thick borders around Titles.
Center your text in the cells.
Set your precision (the number of decimals displayed) etc.

Note:
Just hover your mouse over the icons in the menu ribbon, wait for a second, and a little text box will appear with a description of the tool you are hovering over.

Some icons have a little arrow next to them, click on the arrow to see all of the different options available.


Don't forget to list the units you are using!

Printing:
I like to format everything for the printer right from the start so I don't have to re-size everything later.

Re-size columns and rows so you can easily see data, and so your table is centered on your page:

Clicking on the upper left hand corner highlights all of your cells so you can format everything (like the font size, and precision) together:


You can also select individual columns and rows to format:


Same thing with columns, just click on a column (A, B, C) instead of a row.

I like to change the cell color in the top of the table to light grey:


Entering equations:

Create a table for your constants, rename the cells
c6→so
c7→vo
c8→ao

Just highlight the cell name, and type a new name into it.  When you are referencing this value in your equation, you can now use a variable name, instead of a cell name. 

Type in your equations:
Think of it just like typing something into your calculator.

Highlight a cell, start with "=" and tell it what you want to do.

Notice the color coding to keep track of what cells are in your equ.

Once you have an equation in one cell, you can copy it down to the other  cells - just select the cell you have, grab the green square in the lower right hand corner, and drag it down.

Cells that you have renamed (like dt) will not change their value when you copy your equation down.

If you did not rename your cell, but you want it to be the same, use dollar signs.

$C$11 - will keep C11 through all calculations.
$C11 will keep "C" the same, but 11 will change to 12, 13, 14 etc. as you copy it.

Note the F4 key is the shortcut for adding dollar signs.
put your curser over the cell name in your equation
Hit F4 once for two dollar signs ($C$11)
Hit F4 again and again for other combinations ($C11, C$11, C11)Graphing Data:

Highlight your entire table (including the titles t(sec), distance (ft), v(ft/sec), etc...

Insert →Chart→Scatter (xy) chart

Excel creates a default graph with 3 data sets (distance, velocity, and acceleration) all graphed against time.

Let's make three separate graphs, instead of one graph.

Copy the graph to make three graphs:
select graph, Ctrl+C, then Ctrl+V to paste.

You can select and delete lines off of each graph so that you are left with only one line per graph:

 

Now we need to get rid of the legends, and add axis labels
x→time
y→distance, vel, acceleration etc.

Just select a graph, and click on the (+) to add axis titles.
Click on the paintbrush too to see editing tools there!

Label all of your graphs correctly:

For your Mousetrap Car data, you will need to add a trend line to your graph.

Just select your line, right click on it, then select "add trendline"

If you select the trendline, there is a menu to let you display the equation, select what kind of a fit, etc.


When data is not perfect, it is better to calculate Vel and Acc off of a nice smooth trend line.  Engineers use trendlines a lot!

Note,
R-squared = the coefficient of determination (a measure of how well the model fits the data). Perfect fit → R-squared = 1.
horrible fit →  R-squared = 0

If you want, break your line up into two lines, one that is 0>t>4, and one for 4<t<10.  Fit two different lines.  times above 4 should fit perfectly to a linear line.

Note: Do you have a different version of Excel?
Just youtube it to figure it out!!
Youtube → search "How to create a graph in Excel 2009" etc.
Think of it like driving cars - once you can drive a toyota, you can drive a honda too, the basic ideas in all of the versions are the same, you just have to find where they moved all of the buttons to.


Don't forget to save your work often!  
If you forgot your USB drive, just email your work to yourself - save it via email.