topic UCS Rotate about Z and pick new origin in AutoCAD Forum

UCS Rotate about Z and pick new origin

Julio_Soto — Fri, 19 Feb 2021 14:49:02 GMT

I'm sure this is a setting but I can't find it.

OOTB when you use the command UCS, then select "Z" you are prompted to either enter an angle or pick a point that will define it. That point is actually the 2nd point because by default the 1st point is the UCS origin.

Apparently, the default was that you would pick both the first and second points. I have a user that wants it to work this way. And it must be possible because his ACAD 2020 in the office works this way, but his ACAD 2020 at home works as I described OOTB. I confirmed that this is actually happening.

There must be some setting to change the way this works but I can't find it!

Re: UCS Rotate about Z and pick new origin

davinatkins — Fri, 19 Feb 2021 18:00:41 GMT

Kent was absolutely right, my answer was totally wrong. Sorry about that - thanks Kent.

Re: UCS Rotate about Z and pick new origin

Kent1Cooper — Fri, 19 Feb 2021 17:55:24 GMT

@davinatkins wrote:

The USC command actually has 2 different command line options for rotating along the Z axis. Z and ZAxis. The Z option rotates the UCS around the existing UCS origin. The ZAxis option let's you first select a new origin point, and then rotate it.

....

Not correct. The ZA option doesn't rotate the UCS XY plane about the Z axis, but establishes a new Z axis direction.

Re: UCS Rotate about Z and pick new origin

Kent1Cooper — Fri, 19 Feb 2021 17:59:17 GMT

Don't use a Z-based option. Note the UCS Prompt:

Specify origin of UCS or [Face/NAmed/OBject/Previous/View/World/X/Y/Z/ZAxis] <World>:

{so pick a point for a new origin, then you get:}
Specify point on X-axis or <accept>:

{which rotates it around the Z axis}

Re: UCS Rotate about Z and pick new origin

davinatkins — Fri, 19 Feb 2021 18:04:25 GMT

Type the UCS command, and just click the new origin point without typing anything. It then allows you to select the angle of the X axis, which is technically rotating around the new Z axis. Is this what you wanted?

Re: UCS Rotate about Z and pick new origin

j.palmeL29YX — Fri, 19 Feb 2021 18:05:01 GMT

@davinatkins wrote:

The USC command actually has 2 different command line options for rotating along the Z axis. Z and ZAxis.

That is not quite correct.

The option Z rotates the UCS about the Z axis by a defined angle (either you type a value or you pick the new angle). The direction of the Z-axis it not changed, only the XY-plane rotates around the Z-axis.

The ZA option defines new direction (and position) of the Z-axis. The UCS origin is moved to the first point and its positive Z axis passes through the second point. The direction of the X- and Y-axis is defined by internal rules and cannot be influenced by the user.

Re: UCS Rotate about Z and pick new origin

Julio_Soto — Fri, 19 Feb 2021 21:15:23 GMT

The only problem with this is that the user does not want to change the origin, just the rotation about the Z-Axis. He wants to keep the origin but change the rotation about the Z-Axis by selecting [2] points on a line that does not cross the origin.

Re: UCS Rotate about Z and pick new origin

Julio_Soto — Fri, 19 Feb 2021 21:20:02 GMT

So I found the solution. It has to do with the selectability of the UCS icon. If the UCSICON is selectable then when you invoke the UCS command and try to rotate around any axis it will use your current origin as the 1st point then prompt you for a second. If the UCS is NOT selectable then you will be prompted for both 1st and 2nd points.

The UCS command does not assume any origin when the UCSICON is NOT selectable.

Personally I love being able to select and manipulate the UCSICON, but not everyone feels the same

Re: UCS Rotate about Z and pick new origin

Kent1Cooper — Fri, 19 Feb 2021 21:49:17 GMT

@Julio_Soto wrote:
The only problem with this is that the user does not want to change the origin, just the rotation about the Z-Axis. He wants to keep the origin but change the rotation about the Z-Axis by selecting [2] points on a line that does not cross the origin.

Can that be right, considering the last three words of the Topic? But if picking two points uses the first one for the "wrong" purpose, they should be able to use the Z option and then (getangle) [or they may need to use (angtos (getangle)) ] to have it use the two picked points only to establish the angle.

Re: UCS Rotate about Z and pick new origin

Julio_Soto — Fri, 19 Feb 2021 21:47:41 GMT

It looks like I miss spoke in the topic. I did not want to actually create a new origin. I wrote that topic poorly.

Re: UCS Rotate about Z and pick new origin

Kent1Cooper — Fri, 19 Feb 2021 21:51:45 GMT

[The timing was such that I think we "crossed in the mail" with me editing my previous reply as you were replying to it. I just want to be sure you noticed that I added something to it.]