Discussion Forum

Hello Mickael,
In 3D, the Design Module offers that capability; we call it "Thicken". See www.comsol.com/design-module .
Best,
Jeff

Dear Jeff,

thank you for your fast reply.
Unfortunately, I'm mostly interested in creating 2d-Geometries.

Is there also a function for such kind of geometry creation in 2d?

Best regards

Michael

Hey Michael,

I'm not sure if you need this anymore, but I was searching for the same thing for days now and I finally had to come with my own solution. So, if you would like to have the equivalent of AutoCAD's "Offset" command in Comsol, and if a circle is the geometry of interest, then do this:

1. Define the following parameters:
R - for Radius (in m/mm/in/ft)
dx - for the offset (in m/mm/in/ft)

2. Create the geometry:
Geometry > Create Circle (with a radius R)

3. Create the offset:
Geometry > Transforms > Scale

4. Configure the scale:
Select the circle as an input object, and on the scaling factor box write the following formulas:
"1 + (dx/R)" if you want an outside offset
"1 - (dx/R)" if you want an inside offset

and make sure that you have the "Keep input objects" selected.

You will get the same effect as the offset, but with a bit more effort than a simple command.

For a rectangular, you need to make sure that you align the centers, but otherwise, it should work the same (you might eventually multiply dx by 2).

Paul

Hello Michael and Paul,

There is a way to use the 3D thickening capability I mentioned earlier to handle your 2D situation. This method will work even for non-trivial 2D shapes (Scaling only works for very special cases).

The idea is to add a 3D component to your model, bring your 2D curve into a work plane in that 3D component, extrude that curve into a surface, thicken that surface into a solid, add a work plane that intersects that solid, and then back in the original 2D component you use the cross section capability to bring in the intersection of the solid and that last work plane.
This method is illustrated in the attached file. Again, please note that it requires the Design Module.

I hope this helps.
Best,
Jeff

Dear Paul and Jeff,

thanks for your helpful comments.
The solution of Paul is a bit compliated - i want to use complicated lines.
Jeff's solution seems good, but I cannot test it due to Design module.

Thanks and best regards

Michael

This is such a basic command that I was surprised to find that COMSOL doesn't have that capability. I've needed it quite often.

I would also be** very **interested to see this implemented as a feature in the Geometry builder. I spend a lot of effort offsetting my curves by trigonometric calculations.

Hello Kerem, Thayne and Michael,

In the soon-to-be-released COMSOL Multiphysics version 6.0, both a 2D Thicken and a 2D Offset operation will be available, no Design Module required.

The Design Module continues to support 3D Thicken.

Best,

Jeff

-------------------
Jeff Hiller