New Autocad student First week of school need help

[kausi21]

I'm trying to figure out how to draw the channel plate in Chapter 1 exercises. Does anyone know if there is a video on how to draw this, so I can get the basic concepts down? I was able to draw the other 3 exercises pretty easy, but I cannot grasp how to even begin on this drawing. When I start the drawing I start with the 0.75 line and make my angles, but when I use the dimensional tool to see if  i have 0.25 in between I can  never get this number. Any help would be fantastic!

[kasperwuyts]

First off, don't use angles for something like this, but x and y coordinates. While in the line or polyline command, type @ 0.25 , 0.25 to get to a point that is 0.25 away in the x and y direction from the last point (the @ sign always makes the coordinate relative to the last point) . If you dislike always having to type @, you can turn on the Dynamic Input by pressing F12 in Autocad versions up to 2014, so you always work with relative coordinates.

Now, after a year of Autocad experience I would probably draw this using rectangles, chamfers, manipulating grips, using the 'tracking point' or 'from' tool, but you need to get the absolute basics down first.

video for more info:

https://www.youtube.com/watch?v=C5AEean_SDE

[JDMather]

Attach your dwg file attempt here.

If you do that - someone will create a Screencast once they understand where you are having difficulty.

[kausi21]

This is as far as I can get. I cannot figure out how to make the .50 in between where the C actually opens up. 

[JDMather]

Forget about that for now.

Type O and hit Enter.

Type .3 and hit Enter.

Click the vertical line and then to the right of the vertical line.

Type O and hit Enter.

Type .2 and hit Enter.

Click the lower horizontal line and then click above the lower horizontal line.

Click the upper horizontal line and then click below the upper horizontal line.

If you know how to add the .125 chamfers - do that now.

Attach your dwg file here so that the progress can be checked.

[kausi21]

That offset command was awesome. Here is what I did so far. 

[JDMather]

But somehow you only Chamfered .05 rather than the required .125  did you use the Chamfer command, d Enter for distance, type .125 Enter Enter then select your lines?

I think maybe that is the problem - you are not changing the Chamfer distance - be sure to read the command line prompts.

[kausi21]

Oh no I did @0.125, 0.125 than I trimmed Let me go back and try what you said.

[JDMather]

Create the vertical line shown red here.

[JDMather]

Offset the red line .5 to the left as shown.

[JDMather]

Offset the line shown green by .375

Offset the line shown yellow by .375

[kausi21]

ok

[JDMather · Accepted solution]

Start the Chamfer tool again d Enter, 0 Enter Enter to set the chamfer distance to zero.

Select the green line where you want to keep it.

Select the inside red line where you want to keep it (on the top side)

Select the horzontal white line where you want to keep it.

Select the red line where you want to keep it.

Select the green line where you want to keep it.

Select the long rightmost red line where you want to keep it.

I think you now see how to do the bottom side.

Offset Trim and Extend (or Chamfer) are your best friends (or should be) in AutoCAD.

[kausi21]

Thank you so much. I still don't know how I would have been able to do it without your help. The first Chapter of the book does not saying anything about offset, chamfers, or even trims. Yet it give you an exercise that seem to require it. Again thank you so much.

[JDMather]

You did really good with minimal instruction.

Back when I was in your seat - the books all want you to count dots like a first grader rather than use the tool in a modern way.

I turned off Grid and Snap to Grid in my second CAD class back in '87 of the last century.

[kasperwuyts]

The book doesn't say anything about trims and offsets yet because this exercise is all about entering absolute and relative coordinates and getting familiar with the coordinate system. The shape is perfectly creatable using only the polyline command.

[kausi21]

If you would like to give me a little information on how it's done using just the polyline command that would be awesome. Using just the polyline command I got as far as I could in the first drawing I submitted. I literally set at my computer yesterday for about 9 hours trying eveything I could possibly do, but even completing the shape I never could get the dimensions to be exactly right. Thats when I came here for help. What JDMather taught me I will forever remember, but if there is another way I will gladly take that knowledge to.

[kasperwuyts]

Imagine the lower left corner of the figure will be the x=0,y=0 coordinate. Start the polyline command by typing pl and hit the return key

Now, type 0,0.25

This creates the starting point of the polyline at the coordinates x=0 y=0.25

Next we go up. The line we have to draw is completely vertical and 0.75 long.

Two most primitive ways to achieve this:

1) Absolute coordinates

type 0,1 and hit return

This creates the line to the next point at coordinates x=0 y=1, which is ofcourse .75 higher than the previous point

2) Relative coordinates

type @0,0.75 and hit return

With the @ symbol, your point is drawn relative to the previous point. You want to add 0 to the x coordinate and .75 to the y coordinate.

Let's use relative coordinates from now on.

Hit return after every line

@0.25,0.25 

@1,0

@0.25,-0.25

@0,-0.125

@-0.5,0

@0,0.175

and so on and so forth.

If you make a mistake, just type U, if you've drawn the last point before closing the figure, you can type C and autocad will automatically close your polyline for you.