Accurate bounding box dimensions?

[david]

Hi everyone,

Today's question: Is there a way to get an accurate bounding box of a solid?

The attached screencast describes my problem.

Thanks for watching!

Best

David

[david]

Further thoughts about the question:

As the surfaces are NURBS coming from Alias, I've been thinking the bounding box could have been defined by the control vertices (CV's) of these NURBS.

I have checked and if, of course, the bounding box defined by the CV's is larger that the one defined by the actual surfaces, it does not fit the size of the box I got in Inventor.

It is still smaller.

[johnsonshiue]

Hi! The behavior can be geometry specific. It is because the range box is an approximation of the minimum box fitting an object. Sometimes, its calculation can depend on invisible geometry or orientation of the object. Please attach the part here or send it to me directly (johnson.shiue@autodesk.com). We should be able to tell if this is a limitation, or there is a better solution or it is a bug.

Many thanks!

[david · Accepted solution]

here under is the reply I received by mail from @johnsonshiue 

It's a pretty good workaround for me, thanks!

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Hi David,

Many thanks for sending me the files! Indeed, the bounding box seems to be slightly bigger than necessary. The bounding box calculation is actually an approximation, particularly with spline geometry. Getting accurate bounding boxy may cost performance. There is a simple workaround you can use to get the bounding box you are looking for. The part is created orthogonal to the origin planes. You can simply create tangent parallel workplanes by picking one of the origin planes and a face on the body. The resultant workplanes should define the tight bounding box. Simply use Sculpt command and select the 6 workplanes -> New Solid to create the bounding box. Could you try it and see if it works for you?

Thanks again!

Johnson

 

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