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A.Lazebny. Mysteries of Autodesk's Caves

Part 4. Interior

Any architectural form (line, plane or solid) is hollow and has a rather curious and mysterious filling. To get inside the room you should find a door into it.

Having pronounced AutoLISP incantation (car (entsel)) and selected necessary archtectural form we will get an answer <Entity name: 7ef97078> or something like it. And this is the door. One does not know where it leads, to open it you need a key that is also an incantation - entget.

Incantations must be pronounced together and with no errors, otherwise you'll fail. If you use Russian letter instead of the English one (they are displayed equally) the you will be unable to open the door.

So:
(entget (car (entsel)))
The door has opened and we have entered.

((-1 . <Entity name: 7ef97078>) (0 . "ARC") (330 . <Entity name: 7ef95cf8>) (5 . "10F") (100 . "AcDbEntity") (67 . 0) (410 . "Model") (8 . "0") (100 . "AcDbCircle") (10 1219.39 659.067 0.0) (40 . 461.131) (210 0.0 0.0 1.0) (100 . "AcDbArc") (50 . 0.428467) (51 . 2.75422))

You see DXF dotted pairs (with dots) and DXF lists (with no points and having more than 2 values).
-1 is the door through which you have entered but - so to speak - from the back side.
0 is a room name (in particular I have come into the "circle" object).
330 is a door leading to somewhere (we do not know where yet).
5 is a room handle (like its label) 'cause there other rooms with the same name or purpose and it is its order number.
100 is a group name to which the architectural form belongs to. And so on.

The creators explained many values of DXF codes but some in a brief manner and some did not. Just in the same room where DXF code lives it can have different sense depending on its order.

All the rooms are walked over, even trampled, by many beginning diggers. Naturally they are not very accurate and often break things, that's why castle creators foresaw partial restoration of lost elements. Being removed some pairs are restored. Being interchanged they return to their places. Values of many pairs may be modified but only in admissible range. However not all is permitted. Sometimes good doctor cannot cure. There are some pairs that after interchanging destroy the castle. On sorcerers language it is called Fatal Error - unrepairable error.

Almost every user at least once tried to "practise shamanism" but only few risk to look into the doors with codes 330, 360 and so on to investigate found data. Each door has two appearances. The first one is Ename that is named door. It is an ordinary type of door after which we see dotted pairs. The second appearance is Vla-object. Entering it we see more detailed description in a form of property names and values as well as doors like Vla-object leading to other rooms, and we find a list of sorcerer's incantations that can be used for room transformation. Sorcerers call these incantations "methods". To convert door from one appearance to another there are two incantations:
(vlax-ename->vla-object door_name)
and
(vlax-vla-object->ename vla_door_name).


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