Set crosshairs orthogonal to screen (not object) or get screen display angle

[WKolo]

Hi everyone,

I know about ortho mode [F8], polar tracking [F10] and SNAPANG (where I can set an angle of the crosshairs), but is it possible to set the crosshairs orthogonal to the screen?

Or is there any way to get the screen display angle relative to WCS?

I don't want estimated orthogonal crosshairs, I'd like the crosshairs to show up perfectly orthogonal to the screen.

This should be possible, since ACAD shows a perfectly orthogonal rectangle on selection of objects, so the system does know the angle, but how can I get it and set my SNAPANG accordingly?

Any hints on this?

Best regards

[ВeekeeCZ]

Use this line?

(setvar 'snapang (- (/ pi 2) (angle '(0 0 0) (getvar 'ucsxdir))))

[WKolo]

Unfortunately this is not doing the job.

Any ideas?

before:

after:

Is there an AutoLISP variable storing the information (the current 'display angle')?

That would help a lot, I could write some AutoLISP code then.

[Simon_Weel]

Use UCS. Rotate along Z-axis. Then use UCSFollow to either rotate the cross hairs or drawing.

[WKolo]

@Simon_Weel I need to stay in WCS while the crosshairs should be orthogonal to the screen.

I can do that approximately by hand, but there has to be a more precise way to do that.

[ВeekeeCZ]

Post dwgs instead of pictures to take a look.

[tramber]

Use the PLAN command 😉

Edit : 

Or even VPOINT

[WKolo]

@ВeekeeCZ It's drawing-independant. It could be any blank template even from Autodesk itself, so no need to post a DWG.

@tramber Many thanks, I know all of these commands, but I still like to get the current "display" or "AutoCAD window" angle.

Is that not possible?

Take a look at my screen recording:

 

As you can see the crosshairs align perfectly orthogonal when in selection mode.

How does the Software (ACAD, C3D) know that angle? Isn't it stored somewhere deep inside the system?

[tramber]

You are showing us an angle of view relative to the UCS.... 

And I must say that I don't understand the issue. We are seeing usual things.

[tramber · Accepted solution]

VIEWTWIST would be the variable you may search for....

[WKolo]

Let me try to explain:

As you can see in my second screen recording, the current view is set to WCS.

If, just for example, I would like to draw a rectangle it will be parallel to the WCS, but i would like it to be parallel to the screen.

 

I hope I explained it better now.

[DGCSCAD]

If I'm understanding you correctly, to get the screen view relative to the WCS values try:

UCS: V (for VIEW)

UCS: S (save the UCS to any name)

DDUCS

Select your saved UCS then select Details

This can also be obtained through LISP.

[WKolo]

@tramber Yes, that is it! Perfect!

I played around and if I'd like the crosshairs to match the VIEWTWIST angle I have to set SNAPANG as negative value.

For example I have VIEWTWIST = 36.740 and if I set SNAPANG to -36.740 it's exactly what I want! (with default unit and angle settings)

Thanks!

[tramber]

I got you now 😂

(setvar "SNAPANG"(/(* -360(getvar"VIEWTWIST"))pi))

Most often you will need to convert from Radians to degrees .

And I included the negative in 360