×
INTELLIGENT WORK FORUMS
FOR ENGINEERING PROFESSIONALS

Log In

Come Join Us!

Are you an
Engineering professional?
Join Eng-Tips Forums!
  • Talk With Other Members
  • Be Notified Of Responses
    To Your Posts
  • Keyword Search
  • One-Click Access To Your
    Favorite Forums
  • Automated Signatures
    On Your Posts
  • Best Of All, It's Free!
  • Students Click Here

*Eng-Tips's functionality depends on members receiving e-mail. By joining you are opting in to receive e-mail.

Posting Guidelines

Promoting, selling, recruiting, coursework and thesis posting is forbidden.

Students Click Here

Jobs

Changing select tolerance: ASEL

Changing select tolerance: ASEL

Changing select tolerance: ASEL

(OP)
I'm trying to use the ASEL command to select a layer in my model and I noticed that ASEL tolerance does not work very intuitively in my opinion:
Two examples
1)ASEL,S,LOC,Z,3015 -> tolerance = 15.075
2)ASEL,S,LOC,Z,3014.9,3015.1 -> tolerance = 0.2E-8
This goes as stated in the documentation.

I hunted down the reason for the weird behaviour of my model for couple of hours... Is there any means to control the tolerance with some control parameter, so that command 1) could be used "safely"?
Of course, I could use a command like
ALPHA = 0.1
ASEL, S, LOC, Z, 3015 - ALPHA, 3015 + ALPHA
but using command 1) would produce much cleaner code.

I'm using Ansys 9.2.

Thanks for your answers!

RE: Changing select tolerance: ASEL

There are commands within Ansys for layer selection.  I do not have the Ansys documentation handy due to my being out of the office but have you looked at the LAYER, SHELL, and ESEL,,LAYER commands?

I don't have much experience with layered elements to be honest but what if you could have something like this in your code to select the layer of interest:

ASEL     !select the areas containing elements
ESLA,S
ESEL,R,LAYER     !select layer in subset of elements of interest

Just a thought.  I've used the LAYER and SHELL commands only for postprocessing so I'm not sure how useful they'd be outside of /POST1.  What are you trying to do exactly once you select a certain layer?

-Brian

RE: Changing select tolerance: ASEL

(OP)
Maybe I misused the term layer ... my intention is to select some areas which have a certain z-coordinate and which have been drawn perpendicular to the z-axis. After this selection the area is extruded with the VEXT command.

My problem was that the tolerance in the ASEL command was too big, and a nearby area having not the Z coordinate I wanted was selected too.

It just somehow nonpractical (and for me lead to a hard-to-find error in my scripts) that the tolerance in the ASEL command scales with the parameter Z_TO_BE_SELECTED
ASEL,S,LOC,Z,Z_TO_BE_SELECTED
   -> tolerance = 0.005 x Z_TO_BE_SELECTED
In my previous example with numbers the result is:
ASEL,S,LOC,Z,3015 -> tolerance = 15.075

RE: Changing select tolerance: ASEL

Hi,
why not impose the tolerance inside the ASEL command? If I remember well, It would be something like
ASEL,s,loc,z,Z_START,Z_END,0.001
for example.
I'm not so sure because I very seldom have to cope with sel tol problems...

Regards

RE: Changing select tolerance: ASEL

Hi,

I would use the command

SELTOL, Toler

Regards,

Alex

Red Flag This Post

Please let us know here why this post is inappropriate. Reasons such as off-topic, duplicates, flames, illegal, vulgar, or students posting their homework.

Red Flag Submitted

Thank you for helping keep Eng-Tips Forums free from inappropriate posts.
The Eng-Tips staff will check this out and take appropriate action.

Reply To This Thread

Posting in the Eng-Tips forums is a member-only feature.

Click Here to join Eng-Tips and talk with other members!


Resources