topic UCS - How to rotate UCS to match 3D object's rotation. in AutoCAD Forum

UCS - How to rotate UCS to match 3D object's rotation.

jreidKVSUZ — Wed, 05 Feb 2025 19:58:03 GMT

Good day.

I have always had problems with re aligning my UCS onto a 3D object that was Extruded / Sweeped and forgot to copy the lines that was used to create my 3D Solids before doing so. As everyone knows, if you don't copy your lines your use, they are deleted after using the Extrude / Sweep commands. Just recently someone asked "hey how can I get these lines back". I am now that guy.

I have attached a drawing and the object on the right is the one that I would like to SNAP my UCS to so I could draw a circle back using center command to center. The object on the left is how I manually rotate the object, draw the circle as shown and then copy and rotate back to the one on the left. Way to many steps I am sure.

If someone could help out, it would be greatly appreciated!

Thanks, JRR.

Re: UCS - How to rotate UCS to match 3D object's rotation.

leeminardi — Wed, 05 Feb 2025 22:06:13 GMT

If you just want a UCS that has it XY plane coincident with the plane of the end of the torus section simply use the UCS OB (object) command.

If you want the orientation of the UCS such that its Y axis points towards the enter of the torus and the Z axis is pointing as in your original object

then try the following:

Set osnap to center.
Give the UCS command followed by
1. Click #1 to grab the center of the torus end.
2. Click #2 to snap to the center of the torus.
3. Click #3 with ONSAP nearest to specify another point on the XY plane.
This will yield the following:
To get the y axis pointing toward the torus center give the UCS command again followed by Z and (remembering the right-hand-rule) -90°.

Re: UCS - How to rotate UCS to match 3D object's rotation.

imadHabash — Thu, 06 Feb 2025 06:20:46 GMT

Hi,

I suggest to read this LINK . By using Face option you be able to Dynamically aligns the UCS to a face on a 3D object. OR you can use other available option that will help depending to your case.

Re: UCS - How to rotate UCS to match 3D object's rotation.

jreidKVSUZ — Thu, 06 Feb 2025 13:49:03 GMT

Thanks!! I did you last commands. But for 4, instead of Z, I did X at 90 and now I can draw my circle like in the top photo.

Thanks again!

JRR!