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!

*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

Surface Offset Difficulty

Surface Offset Difficulty

Surface Offset Difficulty

Hello ... I am a new user of Unigraphics V18 and I am trying to offset a non-planar surface which has been successful in other areas, but for a few surfaces I receive the error message "Highlighted Faces Failed To Offset."  Could someone explain to me what is preventing the surface from being offset and how I can work around it?
As a solution to this problem I have tried to use an extrusion to offset the surface and apply a thickness.  This has worked, but I haven't found a method to 'sew' two solids together.  Is that possible using Unigraphics?  
Thanks for your help.

RE: Surface Offset Difficulty

 There can be a number of reasons why a surface doesnt offset correctly. Is it imported? Is it sewn, or individual patches? Are there "tiny objects" or other discrepancies in the original surface. Would it intersect itself if offset?
  As far as sewing solids together, you can use unite, or you can choose the solids for the input type in "Sew"
Hope that helps, if not I would be glad to look at it for you...

RE: Surface Offset Difficulty

Hi Shan,

As Derek said there can be number of reasons
I think the offset value you are giving is more,as the surface is nonlinear there will be some overlap of the offset surfaces and the option fails
Try giving a less offset value.


RE: Surface Offset Difficulty

Use examine geometry and check the surface that gives you the problem.

Check then the minimum radius (Analysis->Mininum Radius...) of the surface so you know what´s a reasonable offset value. If there is a problem with small rads use Face analysis and check which region it is.

When you know what the problem is then we can talk about countermeasures

RE: Surface Offset Difficulty

I ran the Examine Geometry on the whole body and it returned a message reading "self-intersecting geometry detected" and highlighted the surfaces which I have been having problems offsetting.  So that tells me that these surfaces need to be fixed.  This particular body can be imported into Unigraphics from a .igs or .stp file and is not a body which I created in Unigraphics.  In this case, can these problems be fixed?
To give you more information about the file I'm working with, it's a model of the human torso which is imported into Unigraphics as a body with a wire frame, but I can select the individual faces (as faces) or the whole body (as a solid body).  As far as I can tell, the surfaces should not intersect when offset.

Thanks again,

RE: Surface Offset Difficulty

Me again ... I understand now that the offset value has to be less than the minimum radius which occurs on the surface.  Can this be worked around though?  I would like all the surfaces to be offset by the same amount and the minimum radius from all the surfaces is 0.003 inches.  Preferably, I'd be able to offset the surfaces by a minimum of 0.04 inches (1mm).


RE: Surface Offset Difficulty

Me once again ... I seem to be quickly finding solutions for myself.  I have solved the offset issues, but now have trouble thickening some of the offset surfaces.  So please don't take any time to try and solve my offset difficulties, they're fixed :)  Thanks for the help!

RE: Surface Offset Difficulty

About the thickening problem, note that you actually are doing an indirect offset operation, so the min rad must be less then the total offset.

I would recommend you to fix/replace the original surface. If the problem is localy just cut it of and apply a new surface with through curve mesh (controlled end strings). If the problem is global then redo the surface, through curve mesh with the sorrounding surfaces and if you need more control strings extract the isoparamtric string of the original surface but check those spline before using.

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! Already a Member? Login


Solutions Brief - Protecting and Rescuing On-Ground Personnel
Keeping our warfighters safe and delivering them a competitive advantage is a key goal of departments of defense around the world. It’s a goal shared by embedded computing manufacturers like Abaco: we never forget who we serve.This case study describes how a major international contractor integrated an Abaco single board computer at the heart of its CAS/CSAR solution. Download Now
Datasheet - Top Enhancements Creo 7.0
PTC's Creo 7.0 has breakthrough innovations in the areas of generative design, real-time simulation, multibody design, additive manufacturing, and more! With Creo 7.0, you will be able to design the most innovative products faster than ever before, keeping you on the cutting edge of product design and ahead of your competition. Download Now

Close Box

Join Eng-Tips® Today!

Join your peers on the Internet's largest technical engineering professional community.
It's easy to join and it's free.

Here's Why Members Love Eng-Tips Forums:

Register now while it's still free!

Already a member? Close this window and log in.

Join Us             Close