topic Re: Mirror in Isometric in AutoCAD Forum

Mirror in Isometric

Anonymous — Sun, 05 May 2019 15:30:23 GMT

Hello,

How to do mirror in isometric?

Re: Mirror in Isometric

imadHabash — Mon, 06 May 2019 07:34:09 GMT

Hi and Welcome to AutoCAD Forum,

>> How to do mirror in isometric?

if you mean while using ISODRAFT command then you have to select the right angle mode to make mirror for your needed place . if this not your question please try to describe more your issue and make a screen shot for your drawing ?

Regards,

Re: Mirror in Isometric

j.palmeL29YX — Mon, 06 May 2019 09:42:29 GMT

I'm afraid @Anonymous is looking for something as attached.

I would not know a solution (in 2D-drafting).

Re: Mirror in Isometric

SEANT61 — Tue, 07 May 2019 08:03:04 GMT

Here is a demo of a workflow allowing limited 'Mirroring' functionality whilst prepping Isometric drawings. As @j.palmeL29YX pointed out, modeling in 3D may be the only comprehensive workflow allowing complete Isometric drawing functionality.

This demo is more of a novelty - pretty interesting in setup and performance, though not necessarily worth the effort unless dealing with only one isometric plane.

Based on the general idea Maxelkat posted here:
https://www.cadtutor.net/forum/topic/9807-isometric-drawing-made-easy/

Re: Mirror in Isometric

SEANT61 — Tue, 07 May 2019 08:11:56 GMT

I should mention: Depending on 'Graphics Performance' settings, the Iso block may suffer a graphics glitch. The drawing database remains intact i.e., The block will print and measure correctly, it will just look like crap.

Re: Mirror in Isometric

j.palmeL29YX — Tue, 07 May 2019 11:34:55 GMT

@SEANT61 wrote:

I should mention: Depending on 'Graphics Performance' settings, the Iso block may suffer a graphics glitch.

Isn't this the same problem as mentioned in this thread (with the same possible solution to repair), is it?

Re: Mirror in Isometric

Anonymous — Tue, 07 May 2019 18:07:01 GMT

@SEANT61 Sir, How you create link between two blocks?

Re: Mirror in Isometric

Anonymous — Tue, 07 May 2019 18:29:45 GMT

@SEANT61 Sir, I have done this.

Re: Mirror in Isometric

Kent1Cooper — Tue, 07 May 2019 19:18:11 GMT

@Anonymous wrote:
How to do mirror in isometric?

The difficulty in this, in purely 2D isometric-mode drawing, is in dealing with different "faces" of the virtual "cube" that the different drawing planes represent, and the fact that AutoCAD doesn't know, for a given drawn object, on which "face" it lies. For example:

To Mirror the red Ellipse [an isocircle] to either yellow position is a basic 2D Mirror operation. But to "Mirror" [in double-quotes because a "virtual" kind of Mirroring, in isometric effect rather than in reality] the red Ellipse across the center of its cube face [the dashed blue center-axis line], to the green position, would actually require a Copy operation, rather than a Mirror operation, at an angle of 330 degrees for a distance of twice the distance from the center of the Ellipse to the Line, but not just the "raw" distance but at that same angle.

To figure out how to get AutoLisp to decide what "face" an object is on [which should be possible for an isocircle, but not necessarily for most other things], and whether you want to "Mirror" it on the same face or onto a different one, and therefore whether Mirror is even appropriate rather than Copy [or sometimes maybe something else], and in which direction to Copy if that's what's needed, is all a very daunting prospect. A 2D-vertical Line like that blue dashed one could represent a vertical line on either the left or right "face" of the "cube," or a 45-degree-diagonal line on the top, and similar ambiguities exist for Lines running in other isometric-axis directions, as well as for other kinds of objects.

And it gets wilder even for simple Lines if they don't run in isometric-axis directions. In the case of the non-isometric-axis-direction angled edges of the parts in @j.palmeL29YX's image attached to Message 3, other alterations beyond just Mirroring vs. Copying would be required. Some of the things in the lower-right part there don't even exist in the upper-left part to be Mirrored or Copied.

If it's at all possible to automate this kind of thing, I suspect it would require asking the User not only for a selection and a Mirror [or "Mirror"] axis, but also for at least some kind of indication of isometric plane, if not for additional input(s).

Re: Mirror in Isometric

SEANT61 — Wed, 08 May 2019 06:00:49 GMT

Look at the file I included in my first post, and examine the relationship between the Block Inserts ProfileOrtho and ProfileIso - insert each individually and Explode to examine the base parts. Then notice the non uniform scaling of the isometric appearing ProfileIso insert.

Those are the necessary steps to create the ortho to iso interlink.

Re: Mirror in Isometric

SEANT61 — Wed, 08 May 2019 06:08:00 GMT

@j.palmeL29YX wrote:

@SEANT61 wrote:

I should mention: Depending on 'Graphics Performance' settings, the Iso block may suffer a graphics glitch.

Isn't this the same problem as mentioned in this thread (with the same possible solution to repair), is it?

There may be a connection. the graphics glitch in my Iso demo can be corrected by unchecking 'High Quality Geometry' in the Graphics Performance window.

In my Iso demo, though, the problem is that the appearance of the non-uniformly scaled arcs - now ellipses - revert back to circular arcs.

Re: Mirror in Isometric

j.palmeL29YX — Wed, 08 May 2019 06:31:24 GMT

@Anonymous wrote:

@SEANT61 Sir, How you create link between two blocks?

I'm not @SEANT61 , but I can show you here how you can do it.

I hope the video is self explaining. Nevertheless some additional comments.

- I inserted the block b-ortho with an angle 44.99999999. Theoretical it should be 45°, but in this case you get problems with arcs and circles (as @SEANT61 mentioned above. See here). I don't know why AutoCAD doesn't work correctly with 45° and it took me a long time to find out how to avoid this behavior. You can also "repair" the demo-block of @SEANT61 : BEDIT the ProfileIso block, rotate it around the base point 0.00000001° (or whatever a small value you want) and save this modification - all arcs are correct now.

- The length of lines in the isometric view are not exact. This is, because I typed rounded scale factors (only 4 digits) while inserting the block b-iso.

The correct values should be:

X-scale: 1/sqrt(2) [0,70710678118654752440084436210485...]

Y-scale: 1/cos(atan(1/sqrt(2))) [1,2247448713915890490986420373529...]

Type as many digits as you want to increase the precision.

- At the end of the video my ISO-block moves away - I forgot while redefining to define the correct base point (and didn't want to repeat the video creation).

HTH

Re: Mirror in Isometric

j.palmeL29YX — Wed, 08 May 2019 06:42:37 GMT

@SEANT61 wrote:

the graphics glitch in my Iso demo can be corrected by unchecking 'High Quality Geometry' in the Graphics Performance window.

Ok, here too. So we get a good result also without the "44.9999..." workaround.

THX