Error in using the STL file

Submitted by ervinodh1126 on Mon, 07/18/2011 - 13:13

I created a new geometry using AutoCaD and exported it as ASCII stl file. I am using the file in my LIGGGHTs input script. When I run the simulation I get the below error message

Importing STL file 'geometry.stl'
Solid body detected in STL file
End of solid body detected in STL file.
ERROR: STL import failed at triangle #0 (line 1), degenerated triangle?

Can anyone please tell me what this error is about and how to fix this error?

Regards
Vinodh

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ckloss's picture

ckloss | Mon, 07/18/2011 - 13:29

Did you check if the triangle is degenerated? Also, try to check if the CAD program is using the right comma separator for export

Christoph

ervinodh1126 | Mon, 07/18/2011 - 16:01

I got it fixed. Thanks for your help. Now I am able to visualize the geometry in paraview. But the particles and the geometry are far apart. Is it got to do with the region co-ordinates? I used the chute_wear example as my reference

ckloss's picture

ckloss | Mon, 07/18/2011 - 16:51

that is probably a post-processing issue. are u using the pizza version from this website?
Christoph

ervinodh1126 | Mon, 07/18/2011 - 17:50

Yes. I am using the pizza from Liggghts website.
Should I change any of the paraview settings ?

When i try to scale the snapshots i get the below error

Traceback (most recent call last):
File "", line 1, in ?
File "/home/s02/s1061629/pizza-16Mar09/src/dump.py", line 442, in scale
for snap in self.snaps: self.scale_one(snap,x,y,z)
File "/home/s02/s1061629/pizza-16Mar09/src/dump.py", line 457, in scale_one
atoms[:,x] = (atoms[:,x] - snap.xlo) * xprdinv
TypeError: unsubscriptable object

and I get the below error message when I use the manyGran() function

Traceback (most recent call last):
File "", line 1, in ?
File "/home/s02/s1061629/pizza-16Mar09/src/vtk.py", line 124, in manyGran
particleGran(file,atoms,names,len(self.data.snaps[0].atoms[0]))
File "/home/s02/s1061629/pizza-16Mar09/src/vtk.py", line 288, in particleGran
print >>f,"POINTS %d float" % len(atoms)
TypeError: len() of unsized object

So I used the many() function to extract the snapshots. Is it because of these error messages that I am not able to view the particles?

ckloss's picture

ckloss | Mon, 07/18/2011 - 17:57

>>When i try to scale the snapshots i get the below error
there should be no necessity to scale the snapshot. Are you using the gran_pizza_17Aug10.tar_.gz version of pizza.py?

Also, please make sure that the first snapshot contains atoms, otherwise pizza may fail

Christoph

ervinodh1126 | Mon, 07/18/2011 - 18:33

I downloaded the 17AUg10 version, even in that version I get the same error message with manyGran() function.

ervinodh1126 | Wed, 07/20/2011 - 14:45

Hi Christoph,

I checked the intial dump file is not empty. I am using the 17th AUg 10 version of pizza. Any input on how to fix this issue will be of great help for me.

Regards
Vinodh

ervinodh1126 | Wed, 07/20/2011 - 16:35

Yes. I tried not to scale the snapshot and I am using the latest pizza version. I am using the below steps in my input file. Is there anything wrong in the way I am doing?

input commands

fix cad all mesh/gran geo.stl 1 1.0 0. 0. 0. 0. 0. 0.
fix granwalls all wall/gran/hertz/history 1 0 mesh/gran 1 cad

/*few commands here */

dump dumpstl all stl 100 dump.stl
run 1
dump dmp all custom 100 dump.flow id type type x y z ix iy iz vx vy vz fx fy fz omegax omegay omegaz radius
undump dumpstl

And to convert to vtk files I am using the standard three steps
1. d = dump("dumpfile")
2. v = vtk(d)
3. v.manyGran()

ervinodh1126 | Thu, 07/21/2011 - 10:43

There is not much difference between the example chute_wear simulation and mine. I just changed the geometry (stl file) and few material parameters. Should I try changing the region and simulation box dimensions to see if the particles and the geometry come closer?

Thanks once again for your help in this.

Regards
Vinodh