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rotate a volume around a centre 1

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jiligeo

Geotechnical
Feb 24, 2005
145
Dear friends, how can I rotate a volume around a defined centre in Ansys?
 
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Hello,

You can use the command VGEN. But first define a local coordinate system (polar or cylindrical) using the command LOCAL.

VGEN works in the active coordinate system. If the system is cylindrical, then X is the radius, Y the angle.

Regards,
Alex
 
Dear Alex thanks a lot for your answer and sorry for late reply. Actually I want to rotate a volume and its corresponding (elements, nodes …) around a centre. I have found Vtran command for this purpose.
My new problem is: how can I define a local coordinate system that makes a rotation on a special centre after transporting a volume to it?
I am modelling a hip joint and I want to rotate femur bone around pelvic. The volumes are created at another program with iges format and they are imported to Ansys.

Regards
Jalil
 
If you truly want to create a volume then by definition you would rotate an area about an axis. You cannot rotate a volue to get a volume. VTRAN is simply to copy a volume from the active coordinate system to the same relative position in another defined coordinate system. It's used to move or copy objects.
 
Dear Stringmaker's, thank you for your reply. I have created the volumes in another program and now I want only to rotate one of them around a special point (femur in acetablum). I do not want to create new volume.
As the rotation point is not at the origin of coordinate system, every rotation makes a transformation at this point too.
My problem is: how can I define a local coordinate system that makes a rotation on a special centre after transporting a volume to it? (without changing the position of this point)
 
Jalil,
You cannot rotate a volume to produce a volume as the output. You can rotate an area however. To do so:

LOCAL !define local CS, should be cylindrical
VEXT !extrudes (or rotates in this case) areas into volumes
 
Hi,
if I understand well, you have plenty of ways to define a CSYS where you want. See LOCAL, CSWPLA, CS, CLOCAL, CSKP.
If you define it as "cylindrical", the move/copy transformation will then be trivial because the Y-coordinate is the rotation (in degrees by default).

Regards
 
Dear friends, I think, I could not explain my problem exactly.
I have two volumes with Iges format, which is imported to Ansys. They are created in Cartesian coordinate system in Geomagic program. Now I want to rotate one of them (after meshing) around a point in Ansys classic. (The point is not at origin)
I do not want to copy a new volume. I just want to analyse a joint at different positions.
Thank you very much for your answers.

Regards
Jalil
 
Fast way:
define a CSYS at the rotation point,
VGEN a rotated copy of the volume+mesh,
delete or unselect the original one.

Regards
 
To add to what cbrn said you can do this in two commands:

vsel !select volumes
vgen,2,all,,,,,,,0,1

Take a look at the VGEN command in the help. Once you have your cylindrical coordinate system defined this should take less than 30 seconds to do.

-Brian
 
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