CFD Online Discussion Forums

CFD Online Discussion Forums (
-   Siemens (
-   -   Coordinate system (

Franch March 6, 2002 07:54

Coordinate system
How can I ***really*** change my coordinate system?

I have I cylindrical object imported in pro*am to be meshed (I have to do it in pro*am). For this model comes from a more complex drawning, when imported, the global cartesian coordinate system doesn't match with any interesting direction of the model.

In particular, I would like one axis to match exactly with the axis of the cylinder (direction of the flow). This way, I will be allowed to have only one primary variable velocity.

But, I suppose, primary variable velocities are defined in the global cartesian system. Even if I change the active system, or I move vertices by VTRANS, I won't be allowed to change volocities...

So, what can I do?

Richard March 6, 2002 08:42

Re: Coordinate system
I think VTRANS is what you want; you can't move the global cartesian system but that's not a problem (think about it ... if everything is relative to the global system, which ultimately it is, then translating or rotating the global system must be exactly equivalent to translating or rotating the vertices themselves). You need to define a new coordinate system which is what you would like the global coordinate system to be, then use VTRANS to rotate/translate the vertices from your new system into the same orientation in the global system. The U, V and W velocities are aligned with the x, y and z axes of the global system, so you should be able to re-align your model so that the "primary direction" is aligned with one of the coordinate axes.

Franch March 6, 2002 08:56

Re: Coordinate system
Thank you, Richard, I was already using VTRANS but in the opposite (and wrong) way, assigning the ***local*** system as first parameter. Now it works, thank you.

All times are GMT -4. The time now is 15:34.