Bag of Holding - volume considerations

[Damon Griffin]

A bag of holding is described as follows:

This appears to be a common cloth sack about 2 feet by 4 feet in size.

Only two dimensions are given. Obviously it has thickness, even if it's only a fraction of an inch. The exact thickness isn't listed because it isn't important, but...

Does an empty bag of holding appear to be a flat, empty sack?

Regardless of what is put into the bag, it weighs a fixed Amount. This weight, and the limits in weight and volume of the bag's contents, depend on the bag's type, as shown on the table below.

Does a partially filled bag of holding still appear to be a flat, empty sack or it it obvious that it contains objects (of a size that would be noticed?) The weight remains constant but does the exterior volume change? And if not...

If a bag of holding is overloaded...the bag immediately ruptures and is ruined, and all contents are lost forever.

If both the weight and [apparent, exterior] volume remain constant, how are you supposed to tell when a bag is close to being overloaded?

Also, why have an interior volume limit at all? Volume stats are only given for containers; for anything else you might put into a bag of holding, you'd have to estimate and then track the volume of a wide variety of differently sized objects, which would bring encumbrance tracking to a whole new level of PITA.

EDIT: This grew out of a question in our most recent session, about whether a bag of holding could be folded up and placed into a normal backpack. If the bag always remains flat regardless of contents, then it can. If the bag is like Santa's toy sack, always appearing full, then it's probably got too much [apparent, exterior] volume to be stuffed into a backpack, especially if the backpack has other items in it already. It turned out that different people in the group had been imagining different things about what the bag looked like when in use.

[bulbaquil]

I always understood it that a fully-filled bag of holding would resemble a (somewhat squished on top and bottom) cylinder with a diameter of 2 feet and a height of 4 feet. On the other hand, I can see the arguments for and against both depictions, and our group plays fast and loose with encumbrance anyway. This is probably a "GM's call" issue... I can't think of any relevant rules that explicitly clarify it.

That said, the interior volume limit is largely irrelevant, unless you're filling the thing with balsa wood or styrofoam. It's only if you fill it with objects less than 10-15% the density of water (depending on the bag type) that the volume limit will be hit before the weight limit will, and most of the time you're going to be filling it with treasure, much of which is made of precious stones or metals that are more dense than water, let alone than 10% of water.

[Cap. Darling]

I like to Think that the magic of the bag dosent tell you how full it is. It is a great item and cheap for what it can do and if you dont really know where you are limitwise it also have a interesting limitation. That is how i run it at least.
Except lost forever is usually just lost on the astral plane and not destroyed.

[Cevah]

Portable Hole sais "it can be folded up to be as small as a pocket handkerchief". This is way better than a Bag of Holding. So I would not let it be a flat sack when full. However, as stated up-thread, it would be a PITA to track volume in the regular backpack to see if the full BoH can fit.

/cevah