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Toroidal Bend Issue

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Toroidal Bend Issue

Looking for some assistance after trying what I believe is everything.

I am developing a tire with a finished profile as a flat.  Once the tread and details are complete, I am looking to apply the bend.  Everything works fine with 1 half of the tread, the bend works.  I finish the other side and the bend fails.

 

Any thoughts?

19 REPLIES 19

Re: Toroidal Bend Issue

I don't open .rar files as a rule, but why are you not making the full 360 degree bend in one feature?

Re: Toroidal Bend Issue

The RAR is just a compressed archive, the model is over 20MB.

I am doing a 360, as stated above, it works with half the tread (SIDE-A), as soon as the other half is activated(SIDE-B), the bend fails.  The results can be found in the file.

 

 Images in attachment - PDF

 

 

Re: Toroidal Bend Issue

Got it.  What if you lay the tread first and then the rotated carcass?

 

Something about boundary blend is like warp where the formed features are copies of the original.

This may be causing a problem.  At least, the carcass appears to be the only common element.

Re: Toroidal Bend Issue

That is the heart of my confusion.

The base extrusion is the reference surface for both ends of the 360.  In fact, I over extruded by a pitch value on both ends, trimmed them back to make sure there was no extraneous geometry to 'upset' the bend.

The fact that it works on 1/2 the tread elements does not help me figure out why the other half fails.

I have had issues in the past where rounds on tread elements make the TB360 fail, and removing those round features resolves the problem mysteriously.  It just means more work to place the feature 1-by-1 after the bend, on over 600 elements x corner/edge count  /sigh.

 

However, I made it a point to not even add rounds or drafts to this one before the bend.

Re: Toroidal Bend Issue

🙂  features such as this always require extra effort. 

You can try accuracy and you can see if there happens to be a tangency at the merged ends.

Sounds like you have the bull by the horns.  Now you just need to wear it down.

Re: Toroidal Bend Issue

Accuracy is already at the lowest CREO will allow.

I have found that if I reduce the amount of pitches on SIDE-A, I can then add the SIDE-B tread at the same number of pitches.  To go beyond that fails the 360 bend.

 

I have also made the change to be able to suppress SIDE-A and activate SIDE-B, basically reversing the original setup.  That works as well, only 1 side will bend.

 

I have done 1 side as a surface and then solidified, tried all variations, with repeatable results.

I have made both sides surfaces, same results.

 

In the end, I can have all tread elements activated on a flat, the bend 'breaks' the model if more than 12 pitches of the tread features.

 

This really looks like a software issue, not a geometry issue.  The only way this can be viewed as having the bull by the horns, is if the horn is attached uncomfortably....

Re: Toroidal Bend Issue

This is not as unusual as you may think.

 

A support case would get you a clearer answer for sure.

When I suggested accuracy, I meant crank it up, not down.

And if you bend the entire treat in one go rather than L and R?

 

I do believe it is the same problem as working with Warped surfaces.

There is something in the underlying definition that makes it a "non-parametric" surface for lack of a better way to consider it.

Re: Toroidal Bend Issue

I think we are saying the same thing on accuracy 😛

I have opened a support case, even referenced this thread into it.

Thanks for the follow up, I will post any updates here.

 

In the meantime, I am updating to M050 now, to see if that magically fixes the problem.

Re: Toroidal Bend Issue

Which version of Creo are you using?

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