View Full Version : Isometric- will fail exam if I cant sort this!!

23rd May 2008, 02:24 pm
Hi there, Im new to this site!
I am doing city and guilds 2d autocad, and have seen that the last exam question is an isometric drawing. I have to draw the plan view of a shape .... from the dimensions given (radius and line lengths). Then draw it in isometric. I can draw the straight lines in iso mode but I am struggling with the curved edges?! Is it isocircles i need to use?? Because ive tried and they dont seem to be at the right angle ?? :( Im stressing over this big time...its sooo frustrating!!!!

Cheers, Kate:cry:

23rd May 2008, 02:36 pm
Isocircles would make sense. And yes, they tend to appear "off" but that's why they're isocircles and not plain circles.

23rd May 2008, 02:37 pm
I know theyr not plain circles, that looks even stranger lol!! but they are not the same as on the drawing. im soooo not getting anywhere with it!!! :( cheers anyway though xx

23rd May 2008, 02:44 pm
In what way are they "not the same"?

23rd May 2008, 02:52 pm
they seem to be smaller and narrower than the exam paper. i cant really explain on here...i just dont know how to do radius' in isometric ! xx

23rd May 2008, 02:57 pm
The radius, by default, or the diameter can be specified on the command line by typing in the appropriate value. What units are you working in?

23rd May 2008, 03:30 pm
working in millimetres. i have tried the isocircles by typing the radius etc. maybe im using the wrong start points etc. i just dont have a clue! any1 know of any good websites or anything? Xx

23rd May 2008, 03:49 pm
Try the Ellipse command in the plane you need to be in.

23rd May 2008, 03:58 pm
tried it!! perhaps i shouldnt have posted on here.....im a complete novice at isometric...i dont really understand it at all!! xxx

23rd May 2008, 04:28 pm
The "start point" is always the center of the circle because AutoCAD wants to default to the radius of the circle as the expected input. Try not to get too excited.

As long as you know the radius you want to use you can determine where to start your ellipse (isocircle) relative to any other lines in your drawing.

23rd May 2008, 04:42 pm
See if this helps. It's one way to work with ellipses (iso-circles).

The red lines are offset a distance equal to the radius. The isocircle's pickpoint is placed at the intersection of the red lines. The trim command is used to get rid of the portions of the isocircle that aren't needed and we end up with the corner radius you see. Example reads left to right.


23rd May 2008, 06:01 pm
Have you looked at this (http://www.cadtutor.net/tutorials/autocad/drawing-aids.php#Tips)?

JD Mather
24th May 2008, 12:42 am
Use Ortho tracking rather than Polar and Direct Distance Entry rather than Offset. After dimensioning issue the dimedit command with the Oblique option and enter 30° or -30° when prompted.
isometric snap

BTW - doesn't one normally get instruction on a topic before taking the exam?