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Something VERY weird occured yet, and I remember I've seen it before.

In one of my parts there was suddenly the layer .BLACK HOLE, with no items on it. I was in resolve mode and make use of merged geometry, but I sure did not create that layer nor is such defined as a default layer.

I remember some parts before who had that layer, but I thought that was something of anyone else who worked on those parts.

What can this be?!? Anyone seen this before? Is this some ptc programmers joke? Is this something for the bugs & builds section?

Wondering, wondering...

Hugo van Andel


Allow me to explain what has happened. The 'black hole' layer is a special layer, which is supposed to be invisible to the user, which is used as the underlying implementation of 'Hide' (which you may find as an RMB option in the Model Tree on various types of items, and has the effect of hiding the item as if it were on a blanked layer, without having to make a layer, and this hiding is only for this session, and is not saved with the model).

It is a natural and harmless thing to exist in your model, but it should not be presented to the user at any time. To alleviate confusion in the future, I have filed an SPR against the behavior so it may be corrected in future.


Matthew Ender

Director of 2D Applications and File Systems

(and incidentally responsible for layers)


it is nice to see that PTC answers directly on serious problems of the software

well done Mr Turk !!
i've also seen the mysterious black hole layer, but only when working on parts in an assembly.

i guess it is better than a brown hole. ;)