NX 5 Alerts

[NXdesigner]

In NX5 alerts are provided for some of my blend features stating that I have X number of tiny objects. In this specific case I have six identical 90 degree edges within the same blend. The alert tells me I have four tiny objects. (Only four of the six? ) After doing an "Examine Geometry" using both the solid body and faces, the analysis says that there are no tiny objects found. Where are these four objects coming from and can this alert be resolved? Is this related to the part being originally created in NX2?

 

[Xwheelguy]

I suspect the Alert is from tiny objects being created in the blend faces of the Edge Blend you're applying. If you performed an Examine Geometry after the model was complete, then those faces might be modeled away and not show up. If that IS the case, then you're OK.

Try rolling back your part history to the blend feature with the alert, then run Examine Geometry and see if you now have the Tiny Objects.

Without having a part file to look at, it's hard telling what caused the alert to begin with. Sometimes you have to blend individual edges or play with the ordering to get things to work out OK.

If you do not have to meet a customer requirement, I wouldn't get overly concerned with tiny objects unless you have issues downstream, with something like FEA or CAM programming.

Tim Flater
Senior Designer
Enkei America, Inc.

http://www.enkei.com

Some people are like slinkies....they don't really have a purpose, but they still bring a smile to your face when you push them down the stairs.

 

[NXdesigner]

Tim,

The Examine Geometry is at the rolled back state and there are no down stream feature that would consume these objects. Unfortunately, this will be used for FEA. I'll try the reordering and removing the edges.

Thanks.

 

[hudson888]

It may be the case that the modeling tolerance and the examine geometry tolerance are set differently. What might be occurring in that case is that the checks performed as the model is constructed and/or during updates are being performed using the modeling tolerance and are therefore probably irrelevant.

The checks that are to be performed during modeling can be set in the customer defaults. I would not turn tiny objects on during modeling. I would just turn on self intersecting.

In order to make good models to sensible tolerances lets say we want to work in metric to 0.02 and 0.5 degrees. Then I would set my modeling tolerance to 0.01 and 0.25 degrees so that I am targeting exactly half the final value. After several features may have been applied adjacent to any given area you could expect NX to have used up some of that tolerance to resolve things like blends etc... So that is why I do so.

In various environments I either run the examine geometry checks as part of a process like checkmate, or simply by setting up a macro. Tiny objects are not among the items that are always considered essential to fix, although it would be always be better if you could. The main ones are the four Body Checks, and the four Face Checks. I permit absolutely none of these defects ever. I apply that with only one condition in mind, which is that it only counts as applied to the finished model. So that if a defect is swallowed up and modeled away by another feature or fix then of course that is okay.

For really simple models you don't need to set and check all of this most of the time NX can make a simple nuts and bolts pistons and brackets design without extensive geometry checks. If you're working with sewn surfaces lots of draft and face-face blends then you really do need to quality manage your outcomes but otherwise in my opinion you could be overdoing things to really bother with this.

Best regards

Hudson