Practice drawing - Rings

[RetroCAD]

Many students find this one to be especially vexing. It is a good intro to commands that use existing objects to position others. Also, trimming is fun!

 

Draw the rings!

[steven-g]

You should try the new trim command (2021), it would take all the 'fun' out of the exercise.

PS it is fun it just works, no selction needed first, just pick what needs to go.

[Dana W]

4 hours ago, steven-g said:

You should try the new trim command (2021), it would take all the 'fun' out of the exercise.

PS it is fun it just works, no selction needed first, just pick what needs to go.

You like that too huh?  I find it very convenient to automatically trim back to the two (or only) nearest fences without going through select first.  Only thing is my ancient brain stem takes over and defaults to selecting first almost every time.  

[Dadgad]

It sounds like they may have set the default for the TRIM command to TRIMALL?

That is the only one I have used pretty much forever, I hate picking the objects to define them.

[Dana W]

You mean it's not new?  Dang it.

Edited May 20, 2020 by Dana W

[Dadgad]

It has always been that the Default option was to   Select objects, 

and if you look at the commandline and read it, like this.

 

TRIM Select objects or <select all>

 

If you just pass on the suggestion of picking objects and hit ENTER>  (which I always do)

it sounds like you get this new fangled pick whatever you want to trim, which seems to be getting rave reviews

from "the usual suspects". 

 

Sounds like the commandline may now read like...

TRIM Select all or <select objects>?  
 

But, I have certainly been wrong before? 

Hopefully wil live long enough to be WRONG again.

I love mistakes, they've taught me everything I know!

 

The image is supplied to help elucidate for those who are new to AutoCAD.

Definitely could have saved TRIM clicks by just doing half of it and mirroring! 

 

 

Edited May 23, 2020 by Dadgad

[eldon]

In my help file from 2002, it says, amongst the information for TRIM command:-

 

"Select the objects that define the cutting edges at which you want to trim an object or press ENTER to select all objects as potential cutting edges......"

 

Perhaps the command has been 'improved' over the years by not having to press ENTER.

[steven-g]

I think it is more than just a simple change of the defaults, indeed now the default is trim acting as though everything is selected, but the projection mode is I think something new, probably not of interest for most people but a definate difference to how the command works, or at least in theory.

[eldon]

Anyway, useful for making a chain look tidy.

 

[Dadgad]

2 hours ago, steven-g said:

I think it is more than just a simple change of the defaults, indeed now the default is trim acting as though everything is selected, but the projection mode is I think something new, probably not of interest for most people but a definate difference to how the command works, or at least in theory.

 

Cool steven-g thanks for the input.

I wonder if you look in SYSVDLG at the explanation of EDGEMODE, if it is different than the one shown from 2016?

 

[RetroCAD]

6 hours ago, Dadgad said:

It has always been that the Default option was to   Select objects, 

and if you look at the commandline and read it, like this.

 

TRIM Select objects or <select all>

 

If you just pass on the suggestion of picking objects and hit ENTER>  (which I always do)

it sounds like you get this new fangled pick whatever you want to trim, which seems to be getting rave reviews

from "the usual suspects". 

 

Sounds like the commandline may now read like...

TRIM Select all or <select objects>?  
 

But, I have certainly been wrong before? 

Hopefully wil live long enough to be WRONG again.

I love mistakes, they've taught me everything I know!

 

The image is supplied to help elucidate for those who are new to AutoCAD.

Definitely could have saved TRIM clicks by just doing half of it and mirroring! 

 

 

 

In almost all cases, students sat quietly for a long time trying to figure out how far apart the rings are. Care to talk about your thought process?

[Dadgad]

I was raised and spent 45 years in the States, did a lot of carpentry,

but typically work in mms, been thinking metric for 25 years now, couldn't be bothered using feet.

Set my -dwgunits to inches and entered decimally, so as to avoid using fractions.

Knowing the overall length I created the first loop, on the left

I then drew a line from the West quadrant of that circle of the overall length, and

Then mirrored that ring across the midpoint of the overall length line.

Copied a ring from Center to Midpoint of the length line.

Copied it again from Center to Mid Between 2 points snaps on the 1st and 3rd rings

Mirrored that second ring across the line midpoint to create the 4th ring.

I think the TRIM is pretty self evident, using the SELECT ALL pick style.

 

In short, create the line of overall length

place two rings at the endpoints and one at the midpoint

copy a ring to the midpoint between the 1st & 3rd, and the 3rd & 5th.

 

Having already drawn it this way I knew my Array spacing should be 54

when doing it again as per the commandline histories shown in the screenshot.

I should have just used LeeMacs Divide lisp, I looked for on his site, wanted to link to it, as it is great, but couldn't find it.

 

This screenshot shows both ways I did it.

 

 

Edited May 23, 2020 by Dadgad

[steven-g]

I also spent many years as a carpenter, and used a similar method, drew two circles then a line from an outer quadrant, but then I just used copy and selected the opposite outer quadrant and pick the end of the line as second point, I then re-seleted the two circles and did a further copy using centre point as the base to mid point of line, and with the same centre still active as base point I used MTP from end point of line to middle (twice). And then just delete the line

[eldon]

As I usually work in metric, the most difficult thing for me would be to enter the length 25'-2½".

 

I would go about it by drawing a line, drawing two circles at the end of the line, move them to the correct place, trim the line and divide it in four, then copy the circles four times.

[steven-g]

Quote

6 hours ago, Dadgad said:

Cool steven-g thanks for the input.

I wonder if you look in SYSVDLG at the explanation of EDGEMODE, if it is different than the one shown from 2016?

 

Edgemode looks unchanged (help files, there is no sysvdlg in LT) so the default may have changed to trimall but the firts prompt was indeed 'Select objects or <select all>: ' and now it reads '[cuTting edges/Crossing/mOde/Project/eRase]: '. But what is new is the projection modes UCS, view and 3D. Plus you can now use line elements in a hatch to act as trim objects (new variable 'trimedges' 0=trim to hatch boundary 1=trim to hatch pattern whilst in quick mode).

[Dadgad]

Thanks steven-g, for the update.  I recall you posted an image many years ago of a project which you had done.

Was it an optical illusion room?  I remember liking it.  

 

In retrospect, were I trying to teach students how to approach this graphic I would probably suggest...

Using the calculator to subtract one External ring diameter from the Overall length, and divide by four. (18'/4 =4'6")

Draw one set of rings and then ARRAY, specifying 5 Items @ spacing of 54"

TRIM to suit.

Edited May 24, 2020 by Dadgad
units added