Sheet Metal Extents

[AJZAdesk1]

Can someone explain the meaning of the extents information in sheet metal flat patterns.  The numbers do not match the dimensons pulled on the pattern.  See attached for an example of the information given by the "extents" command and the dimensions actually pulled on the flat pattern.  What am i missing?

thx in advance

[JDMather]

This would be a lot easier to explain if you had attached the files here.

You are missing some dimensions in the image you attached.

It appears you have a flattened cone which results in an ellipse.

Can you report back what you get for these dimensions?

[AJZAdesk1]

I can’t attach the file.

I'm thinking the extents should reflect the minimum size sheet needed to produce the part. I’ve place the dimensions for what i think are the two possible scenarios (one with max width and one with max length) on the flat pattern inventor provided. Neither matches the extents provided by inventor.  I'm just looking for an explanation of the extents because they don't give the information I was expecting.  This issue is present on the file you worked on for me earlier.  I can get one matching dimension (to three decimal places), but not the other.

[JDMather]

What are the dimensions of your cone?

Also, you didn't answer my question about the dimensions as I indicated.

[AJZAdesk1]

The dimensions are the same as ones already on the file i previously attached.  i've pulled them again and rotated the flat pattern to make it easier to view.

It's not a cone.  It's a series of the corrugations you helped with.  The OD is 126", the ID is 30", and it's a 180° segment.

[johnsonshiue]

Hi! The behavior does not seem right to me. I would like to take a closer look. Could you post the file here or send it to me directly (johnson.shiue@autodesk.com)?

Many thanks!

[JDMather]

What are these dimensions?

Where is the projected intersection?

[AJZAdesk1]

I just installed 2015 and it gives different values for the same part but the dims still don't match the extents.

[JDMather]

It would be more definitive to have your actual files, but a little trial gets close.

[RobJV]

Without looking closely at your issue, have you simply tried to RMB on the flat pattern and chose "edit flat pattern definition?  You can then place it in the orientation that makes your extents make sense.

Rob

[JDMather]

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@RobJV wrote:
  You can then place it in the orientation that makes your extents make sense.

Rob

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I think that sounds easier than it is.
I do not see an option to set the horizontal (or vertical) orientation of the extents box.

The flat pattern will be at an angle within the box.

I do not see an (automatic) way of showing the extants box - I had to construct one with dimensions and constraints.

[RobJV · Accepted solution]

What I am saying is that typically to get those numbers, the extents will match the orientation of the flat pattern part.  (Obviously if it does not, then there is something wrong.)  If the op simply looks at the flat pattern and then uses that horizontal edge to align the "ucs" when he is editing the definition, the new extents should match the overall x and y size that is displayed on screen.  It looks as though he is dimensioning a different orientation in the drawing than what the flat pattern orientation is.  (Would be much easier if he simply attached the ipt)

Rob

[AJZAdesk1]

That's the piece of the puzzle I was missing.  I was expecting an optimized (minimum area) solution.  Now i know it is based on the orientation of the flat pattern.

thx

[RobJV]

No problem. You are welcome.

Rob