Hello,
Probably a really simple question... but when you initially insert a mesh, where does it place it originally before any offset is applied? At the origin of the simulation region?
I am just trying to understand how it inserts so I know that my mesh is placed correctly. I have looked at the fix mesh/gran help file but it doesn't say how it picks the point of reference of the inserted mesh and if the point of reference in the region is indeed 0 0 0.
I used solidworks to create the STL file if this is of any use in answering my question
Thanks
Jay
ckloss | Wed, 04/20/2011 - 15:00
the command takes the
the command takes the coordinates that are in the STL file. Additionally, you can apply offset, scaling, rotation as given in the doc page
Christoph
raguelmoon | Wed, 04/20/2011 - 16:20
Hi, You should create
Hi,
You should create geometry at 0 0 0 coordinate in CAD software before exporting to STL. However, you can move the STL file later in simulation box by applying offset and rotation values, but it will create problems when you apply move, wiggle to it. Therefore, I recommend you to fix geometry in CAD software before exporting for LIGGGHTS. There are many mesh generating softwares in which such facility is available. For example, gmsh, Maya, FEMAP. I use Maya which is easy to use for this purpose.
Best,
Ram
ckloss | Wed, 04/20/2011 - 16:27
>>by applying offset and
>>by applying offset and rotation values
>>but it will create problems when you apply move, wiggle to it
this is not true... we have done this many times, and have a look at the moving mesh example, it's done here also
Christoph
raguelmoon | Wed, 04/20/2011 - 19:08
Dear Christoph, I have done
Dear Christoph,
I have done one simulation in which mesh(cylinder) was not created with origin in CAD software. When I applied rotate it didnt rotate around its axial because its origin was outside the geometry. However, STL geometry was in the simulation box at origin points. I set STL file with offset and rotaion values in order to fit it in box. But when I created STL at origin in CAD and imported in LIGGGHTS, it worked fine with zero offset values etc.
Thanks,
Ram
ckloss | Wed, 04/20/2011 - 19:11
>>When I applied rotate it
>>When I applied rotate it didnt rotate around its axial
>>because its origin was outside the geometry.
For fix move/mesh/gran, you always have to provide the axis you want to rotate around.
There is no automatism like "move around center axis of STL"
But that's not a bug - the feature just does what is said in the doc
Christoph
raguelmoon | Wed, 04/20/2011 - 19:27
Hi, Yes, I did what doc pages
Hi,
Yes, I did what doc pages tell, my cylinder lies along y-axis. I also posted query regarding this problem:
node/311
But, I solved this problem by CAD software.. I will again try this next time.
Thanks,
Ram