isometric dimension to center mark of ellipse/diff length dim lines?

[steve.yarnall]

using down time to build 3D skills. an online tutorial ( http://we-r-here.com/cad/tutorials/l...xtra_3-001.gif ) shows an isometric dimensioning of an ellipse where the dimension line extends to a center mark of the ellipse in both axes. plus one of the extension lines is longer (to the center mark) than the other (to the corner of the object) too. using the dim align or the dim hor/vert mode can not grip & extend one extension line w/o changing the dimension ..how do you get diff length ext lines with one extending to center of ellipse?...also how do you get the center mark on an ellipse in isomode?

see attachment too.

[buzz]

Is there a reason you don't just draw the part in 3D (as opposed to drawing it in isometric)?

Unless the part is drawn in 3D, I don't think you can use AutoCAD's dimensioning tools since an isometric is a 2D depiction of 3D and therefore does not have depth.

To display those dimensions in an isometric drawing you would need to create them from scratch, but I would recommend learning true 3D in your downtime...

-Buzz

[Richard.Kent]

First off congratulation on your first post.

I assume you are drawing a 2D isometric even though you mention learning 3D.

If you are in 2D, snapstyle isometric, then you have to dimension using the aligned dim method and then dimedit, oblique, <enter and angle> to get to that shown on the bmp. I am not sure how they would have gotten the dim extension lines to two different lengths. My guess is they exploded the dims or used DIMASSOC = 0 and then stretched them. I prefer to draw longer center lines rather than just showing center marks.
I am attaching a drawing that I use for iso dims that has dim styles, text styles and dim arrows set for iso dims. There are some instructions in the drawing to help.

All that being said, as much as I love isometrics, I would start learning 3D rather than spending much time on isometrics.

If you need any further help with the isos post back.

[jaberwok]

The object type Ellipse has only a single "centre" snapable point.
The old-style polyline approximation to an ellipse has four snappable centre points - one at the centre of each of four arcs (just like using compasses).
To create old-style ellipses, set the variable "pellipse" to "1" before you start.

For the dimensioning, try using dimlinear and the "rotate" option.


edit - aDesk have been threatening for years to remove the variable "pellipse" but, as of A2008, it's still there.