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Far March 3, 2013 11:33

ICEM sizing function >>> Gambit and Ansys meshing
How do we apply sizing function in ICEM...

I think it can be:

1. Density box

2. Tetra width and tetra ratio

How we can relate them to sizing function of Ansys meshing and Gambit. I am asking this because recently I was asked by someone to make the volume mesh (tetra + prism) in ICEM and he provided me surface mesh made in gambit. I was surprised by the mesh quality. Mesh was very fine near leading and trailing edge and coarse in centre with very smooth transition. When asked, he saaid" he used the sizing function of Gambit". Similarly I saw the examples of Ansys meshing and sizing functions were superb (I heard sizing functions in AM comes from Gambit!!! is it true).

Is it possible to get the similar size functions in ICEM and how to activate them?

PSYMN March 4, 2013 10:38

Yea, but only when using Octree Tetra... The Gambit size function actually generates an octree background mesh behind the scenes... Old Gambit users may recall that you could actually view it in Gambit. But the gambit one is a bit smoother because it ends up generating a delaunay like advancing front grid instead of using the octree grid directly.

Anyway, go to the mesh tab => Global mesh size. Turn on the options for "Curvature/Proximity Based Refinement." The "Elements in Gap" and "Refinement (cells in 360)" are goals. The Min size is a limit. You can also set a smaller min size on each surface or part if you have this turned on.

Give it a shot and give us some feedback.

The Gambit size function has been added to ICEM CFD MultiZone if you are using unstructured blocks. You will see it more and more...

PSYMN March 4, 2013 10:41

And actually, just for the record, it is not really the Gambit sizing function.

Before ANSYS bought Fluent, Fluent was already working on a replacement for Gambit. This sizing function had been developed for that. So, technically, it is the "son of Gambit" sizing function... It is better than the Gambit Sizing function and I don't think it was ver actually in Gambit, but it was developed along the same lines and by the same people and we still call it the Gambit Sizing function in house. :cool:

Far March 4, 2013 11:32

Thanks for this info and I was not aware of this latest development at Gambit. What I dont understand is that Gambit could have been modernised with more geometry, solver output and tetra options to compete with meshers like ANSA. But it is just my personel point of view and I dont know about the business at that level.

PSYMN March 4, 2013 11:46

Software architectures always have limitations. Some may be due to limited initial scope, others due to hardware developments that the software was never designed to utilize. It is important that a software vendor recognize those and have the courage to take a step back so they can take two steps forward. The new meshing architecture we are working on will be worth the wait...

Actually, I recently noticed that ANSA has a new UI... not sure if that is an architectural change or just face paint, but, as painful as it is, change is inevitable if you want to stay ahead in engineering software.

aat March 4, 2013 16:27

This may not be entirely relevant to the current topic, but the note about Gambit (in a more modern incarnation) caught my eye.

I don't know if any of you have seen or used Cubit from Sandia (the latest commercial incarnation is called Trelis and developed/supported by CSimsoft). There are common roots between the Gambit and Cubit/Trelis in development, GUI layout as well as in the meshing algorithms, including sizing. Just wanted to inform posters that many of Gambit's technologies still survive, outside of ANSYS, in a modern form and minus the platform limitations Gambit eventually ran into.


(For full disclosure, I represent a distributor of Trelis. If you are interested in learning about Trelis, you can visit CSimsoft's website, or correspond with me via email instead)

Far March 5, 2013 02:16


Actually, I recently noticed that ANSA has a new UI... not sure if that is an architectural change or just face paint, but, as painful as it is, change is inevitable if you want to stay ahead in engineering software.
Simon you have good sense of humour :D

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