Learning Forum

[Steve-357]

Thicken Sheet goes the wrong way. It seems like the sheet thickens in the direction of the normal vector for the surface, but how do I change that? In HFSS, I have a line that I have added width to to make a trace, and I'm trying to thicken it to model a 3D trace. Currently, the trace is always thickened in the -Z direction into the PCB dielectric. (PCB is in the XY plane.) It should go in the +Z direction such that the distance to the ground plane underneath is not changed.

[DimK]

Hello Steve-357,

 

Thank you for reaching out to our Ansys Public Forum!

 

Indeed, using the “Thicken Sheet” operation, the sheet is thickened in the direction of the normal vector of the surface.

Since your sheet is on the XY plane (like the PCB is), when you apply the “Thicken Sheet” operation on it, the sheet is thickened towards the Z-axis, since the Z-axis is normal on the XY plane.

But the direction of the thickening is controlled by the direction of the Z-axis of the coordinate system that you are using to draw this sheet.

For example, if the +Z direction of the coordinate system that you are using for the drawing of the desired sheet  is in the opposite direction of the +Z direction of the global coordinate system, when you enter a positive number in the “Thickness” field, the thickening process will be applied towards the +Z direction of your coordinate system, which is equivalent to the -Z direction of the global coordinate system.

If this is the case, a simple “-” sign in front of the “Thickness” field should do the trick (it is allowed to enter negative numbers in the “Thickness” field of the “Thicken Sheet” operation).

 

Please let me know if my response above works for you and if you are able to resolve your issue. If the issue still exists, please share more information about it (e.g. some screenshots of a “sample” project that contains only a sheet, in which you are showing the issue would be very helpful).

 

Best Regards, 
DimK

[Steve-357]

Hi DimK,

Thanks for the response. I only have the global coordinate system in the model, so I still don't understand why the sheet is thickening in the -Z direction. I did try making a relative coordinate system for the part with the Z-axis going in the opposite direction. Even after assigning the new coordinate system to the sheet, it still thickened in the same direction, which is to say the global -Z direction.

I also tried thickening the sheet to a negative thickness. That was actually the first thing I did when I encountered the issue. The model appears inside-out - the view seems to clip inside such that you're always looking at the inside surface rather than the outside of the trace. The issue is when I attempt to plot Jsurf_mag on to the trace, the whole program crashes.

-Steve

[DimK]

Hello again Steve, 

 

Thank you for your prompt response!

As I can see from your last response, you have tried what I have mentioned in my previous response and the issue still persists.

In this case, it would be very useful for the troubleshooting process to share your model or a test one, in which the issue appears.

Since it’s not allowed to share/attach any models/projects in the Ansys Public Forum, I would suggest opening a support case for your issue and attaching your model there (or a test one, in which the issue appears).

This way, we will be able to investigate more efficiently your issue and help you to resolve it.

 

Best Regards, 
DimK

[Steve-357]

Thanks, DimK. I'll do that.