CFD Online Logo CFD Online URL
www.cfd-online.com
[Sponsors]
Home > Forums > Pointwise & Gridgen

Pointwise/Gridgen

Register Blogs Members List Search Today's Posts Mark Forums Read

Reply
 
LinkBack Thread Tools Display Modes
Old   December 7, 2009, 13:58
Default Pointwise/Gridgen
  #1
New Member
 
Brendan Sloan
Join Date: Mar 2009
Posts: 24
Rep Power: 8
Amiga500 is on a distinguished road
Any users here?

How does it stack up compared to ICEM?


I am getting somewhat annoyed at the inconsistencies of ICEM when performing geometric operations.


Or does anyone else have any other meshing software they'd recommend?
Amiga500 is offline   Reply With Quote

Old   December 7, 2009, 17:28
Default
  #2
Senior Member
 
Charles
Join Date: Apr 2009
Posts: 179
Rep Power: 9
CapSizer is on a distinguished road
I've used both, although much more Icem than Gridgen. The underlying philosophies are very different indeed. Coming from Icem, I had much difficulty getting Gridgen or Pointwise to do what I wanted, but I suspect that an experienced Gridgen user going the other way would have similar problems. I would say though that neither is brilliant when it comes to geometric operations. Geometric operations in Gridgen seemed to be much more tedious, but Icem has other geometric frustrations. The grid generator that I quite liked for its ease of geometry handling was ESI/CFDRC's CFD-Geom. Getting the actual grid exported in a useable format may be a problem though. I have to say though, that current (and also future) thinking is biased towards doing most or all geometry in CAD, before going into the mesh generator.
CapSizer is offline   Reply With Quote

Old   December 7, 2009, 19:00
Default
  #3
New Member
 
Brendan Sloan
Join Date: Mar 2009
Posts: 24
Rep Power: 8
Amiga500 is on a distinguished road
Sorry, I wasn't clear when I said "geometric operations".

I mean CAD cleanup, and perhaps subsequent addition of features and details.


I find ICEMs inability to correctly project lines onto surfaces, or subsequently obtain accurate surface-to-surface intersections very frustrating.
Amiga500 is offline   Reply With Quote

Old   December 8, 2009, 02:48
Default
  #4
Senior Member
 
Charles
Join Date: Apr 2009
Posts: 179
Rep Power: 9
CapSizer is on a distinguished road
That doesn't actually change my comment at all. I've come to the reluctant conclusion that if you don't do nearly all the CAD cleanup in the CAD, you will be in for a world of trouble. I had the novel experience in Icem 11 of creating a simple geometry entirely within Icem, passing all the topology checks, and the tetra mesher blithely ignoring my internal geometry. I complained to Ansys, and there reply was "Use Design Modeler". I did, and it worked, but really, if you are simply doing a sphere inside a cube it shouldn't be necessary to resort to CAD!


I share your frustrations exactly, but I found creating extra geometry in Gridgen quite difficult, certainly less easy than in Icem. What I did like about Gridgen was the ability to "quilt" patches together with a tolerance.


It seems to me that the best answer to the "BAD CAD" problem is a mesh generator with a good surface wrap capability, and perhaps Adapco have the answer there.
CapSizer is offline   Reply With Quote

Old   December 8, 2009, 11:41
Default
  #5
Senior Member
 
John Chawner
Join Date: Mar 2009
Location: Fort Worth, Texas, USA
Posts: 221
Rep Power: 9
jchawner is on a distinguished road
Brendan & Charles:

I hope you don't mind if I offer my biased opinions! While I cannot offer any comparison to ICEM (never used it myself) I can address some of the issues you cite in isolation.

Dealing with geometry from a CAD system continues to be a challenge for everyone. ANSYS' relationship with SpaceClaim is evidence of the work going on in this area. I will admit that Gridgen's geometry modeling capability cannot compete with a CAD system - it simply wasn't designed to. By geometry modeling I mean the ability to create geometry from scratch. The software does support creation of many curve and surface types but not a lot and not in the way that a CAD system would do it. The new software, Pointwise, has improved on this somewhat (especially the workflow) and will continue to do so in the future.

Both Gridgen and Pointwise were designed to bring in a CAD model and make it analysis ready. So they both have tools for intersections and projections and trimming. From the standpoint of dealing with sloppy CAD, both offer two approaches: fault tolerance (in which the grid is merged over gaps an junk in the CAD) and solid modeling (where the geometry is formed into a watertight solid). (Note: solid modeling will be released in Pointwise shortly after the first of the year.)

Geometry modeling (including import, export, creation, assembly, etc.) will continue to be an area of focus for us (and I suspect everyone else in CAE) for the foreseeable future. To put it all in perspective, it is reported that the annual cost of CAD interoperability problems exceeds the market capitalization of all CAD companies combined. So I suspect there's plenty of work to go around for all of us.

If you'd like to discuss this offline in more detail, feel free to email me directly.
__________________
John Chawner / jrc@pointwise.com / www.pointwise.com
Blog: http://blog.pointwise.com/
on Twitter: @jchawner
jchawner is offline   Reply With Quote

Reply

Tags
gridgen, icem, pointwise

Thread Tools
Display Modes

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are On
Pingbacks are On
Refbacks are On



All times are GMT -4. The time now is 07:20.