CFD Online Discussion Forums

CFD Online Discussion Forums (
-   ANSYS Meshing & Geometry (
-   -   [ICEM] Meshing .stl surface in ICEM (

kbodla June 22, 2010 16:39

Meshing .stl surface in ICEM
I have just recently begun ICEM and would like to know how would one import an .stl surface mesh and generate a volume mesh for the corresponding volume bound by the surface.



PSYMN June 23, 2010 14:44

There are several tutorials for this exact thing...

File => Import Geometry => STL.

Then "Geometry (tab) => Repair Geometry => Build Diagnostic Topology" to get your curves and segment the faceted geometry by feature angle.

Then right click on parts in the model tree to create new parts (Such as INLET, Outlet, etc.) and add the surface segments to the correct parts.

Create a material point or whatever...

Set sizes.

Hit the button to Compute mesh (using Octree Tetra)

Other than the Import part (which is pretty straight forward), you can see the process at

I recommend all new users go thru the tutorials before getting yourself frustrated and stuck on your own model.


calvin123 December 2, 2010 22:33

ICEM tutorial
I agree with you, it is better to read tutorials first. I am a newer of ICEM too, and I cannot locate whereabout the tutorial manuals, could you please let me know?
I also need to import STL file in ICEM (I tried in Gambit, but it is hopeless of Gambit:().
For my model (human body shape; the geometry is done by other software), I import STL in ICEM and it seems fine, then when I mesh it, I cannot see the human body is meshed, but only the flow domain:confused:.
Could you suggest any possible ways to get the mesh created, please?
Many thanks.

PSYMN January 30, 2011 19:26

Material Points.
ICEM CFD controls which bodies are meshed by the location of material points. If you put one inside the body, then that region is meshed. If you put one outside the body, then that region is meshed. If you put both, then both regions are meshed...

ld1305 January 16, 2012 10:14


I've recently begun work on something similar, however I'm having issues creating inlets and outlets, is there any more detailed instruction available?

Thanks very much

PSYMN January 16, 2012 10:35

Calvin123, I missed your previous comment about not being able to select the inlet and outlet...

The problems is that your STL is all one surface, so when you try to select it, you get the whole thing...

As is often the case, there are a number of solutions. If your inlets and outlets are separated by sharp angles, use "Geometry (tab) => Repair => Build Diagnostic Topology". This tool will break up the STL into separate surfaces based on the angle specified. It can also add curves and points based on that angle, which is great for Tetra/Prism. Once the STL surface is broken up into separate surfaces, you can come back and put the inlet into an inlet part, etc.

If you have regions that you want to separate, but which do not have nature feature angles to automate the break up, there are a number of other methods. Most of the geometry tools (such as split surface at a plane) work with STL geometry also. You can also use the geometry repair tools to split STL or even to select facet by facet (or use the polygon select tool) and "Move to New Part".

PSYMN January 16, 2012 10:36


Please be more specific. Were you just having trouble breaking up the STL surface? The previous comment should help.

Best regards,


Lilly June 28, 2012 13:24

Dear all,

I am a bit confused about the *.stl-meshing at the moment.
When I do "Build Topology" and the curves and points appear on my surface, do I have to erase them later on again? Or are they a sign for a "bad geometry"?
I realized that my surface includes several small surfaces afterwards (due to the curves that appear). Do I have to merge them again or does this not have any influence on the quality of my mesh?
I couldn't find the mentioned tutorials for meshing *.stls. Can anybody maybe post a link please?
Thanks a million for any help!

All times are GMT -4. The time now is 08:07.