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Importing STL/STEP files, un-mesh?

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Old   July 5, 2017, 09:38
Default Importing STL/STEP files, un-mesh?
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Julia
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Hi, I am new, my boss wants me to create a geometry and open it in ANSA to do his mesh. I have scripted my geometry using FreeCAD Python API and in result, I have succeeded to export it in both STL and STEP files. But I have issues with reading them in ANSA. It would be great to receive your help.

STL file:
When exporting my geometry into STL file, some basic mesh is auto-generated. Questions: 1. Is it possible to "un-mesh" it in ANSA? 2. STL files only stores meshed objects?

STEP file:
While solid parts are created in FreeCAD, red lines appear when I read them on ANSA. I created a simple cylinder in FreeCAD, and red lines are defined in ANSA... Usually, where do you go to solve such problems? I can modify the exported step file using a script but I don't know what to modify.
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Old   July 6, 2017, 06:35
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okay, answering my own questions.

1. STL
Receiving help from ANSA support person.

2. STEP
Use the fix button and it went allll good.

IGES exported from FreeCAD seem to do a worse input in ANSA than STEP file.

<3
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Old   July 6, 2017, 07:58
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STL contains only meshes, surface(brep) details can't be stored in stl file. If you export stl files in ascii format, you can open it in any text editor and see what is inside the file
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Old   July 6, 2017, 09:14
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thanks for the info, although is it possible that an stl file can store a solid geometry? When i imported an exported stl file from OpenSCAD, there would be a big fat object without surfaces left after I deleted all the elements (which i am using is mesh).
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Old   October 14, 2018, 13:23
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I recently found myself on the same situation.
Doing some reaserch on internet I was able to find this good tutorial:
http://blog.bantamtools.com/convert-stl-to-step
But the FreeCAD software seams to have some limitation on handling complex shapes. It may work for you.
I found a website to convert the file for me. So far they are a free platform. I recommend to give it a shot.
https://www.cadmeshanalytics.com/
Good luck!
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Old   October 15, 2018, 05:44
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Mahmoud Aboukhedr
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Hii, Your problems are fairly basic, so please find below a quick answer to your questions in RED.
STL file:
When exporting my geometry into STL file, some basic mesh is auto-generated. Questions: 1. Is it possible to "un-mesh" it in ANSA? 2. STL files only stores meshed objects?
For STL, not just in ANSA but everywhere else it's by definition a mesh that contains distorted elements. Moreover, as it defined in Wiki (An STL file describes a raw, unstructured triangulated surface by the unit normal and vertices (ordered by the right-hand rule) of the triangles using a three-dimensional Cartesian coordinate system. In the original specification, all STL coordinates were required to be positive numbers, but this restriction is no longer enforced, and negative coordinates are commonly encountered in STL files today. STL files contain no scale information, and the units are arbitrary.)
So ones you import STL format in ANSA it reads the elements, yet you can remesh the surfaces if need. Please let me know if you are interested in remeshing the STL mesh and reproduce better quilty mesh.


STEP file:
While solid parts are created in FreeCAD, red lines appear when I read them on ANSA. I created a simple cylinder in FreeCAD, and red lines are defined in ANSA... Usually, where do you go to solve such problems? I can modify the exported step file using a script, but I don't know what to modify.

For any import in ANSA, the user must perform so geometry cleaning and topology checks.
Starting from the red lines in ANSA, they mean that the bounds are not connected, To connect them you can simply go for Face > TOPO (under TOPO tab) and select all (Ctrl +A) then confirm by middle mouse .. you should see all red bounds change to yellow.
Also, you can use after FACE > TOPO some tools to clean up the geometry like Hot Points > Clean G. also select all and middle mouse to confirm.
It's important also to check on the geometry penetrations and instructions because this can cause some problems later. You can try From Check Manager > Geometry checks.

If you found it confusing to find any of the functions I mentioned, you can simply search for it on the search bar, and ANSA will point out where to find i.t

Also be aware, it's important to use the latest ANSA versions like (V18 and V19) for this functions to work properly. Als,o its important to use the correct deck (like openFOAM for example) to get the best functions on the ANSA GUI.

Please let me know if that answer was helpful and if you need any further help.

Last edited by Mahmoud_aboukhedr; October 16, 2018 at 05:16.
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Old   November 5, 2018, 12:44
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Hi all,

I'm trying to remesh the surface of an STL file using ANSA , but I get stuck in the process ! is there any tutorials or videos to follow ? or if anyone could help me on that topic.

Another thing is when I export the part as an abaqus.inp file it always opens as as orphan mesh within abaqus how can I get around this ?

thanks in advance
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Old   October 3, 2019, 04:39
Default How to export STEP from Surf using Python scripts ?
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How to export STEP from Surf using Python scripts ? Using Python with 3D Support Packages?
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