Entities supported by the different DWG format generations
Saving back to DWG 2010 format from Bricscad 13 shows a warning box "This pre-2013 dwg format does not support some entities. These entities will not be saved in the drawing. Continue?" which is useful. But what entities are the "some entities" that would not be saved in 2010 (or 2007 or ...)?
A check of the help file and PDF user guides didn't turn up anything (although I certainly could have missed it somewhere).
Comments
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I can only second that guidance on this subject would be welcome.
Neither BricsCAD's nor AutoCAD's documentation explains the changes to the file format, and even looking through the Open Design Alliance dwg reference doesn't help much in deciding which version to use.
My understanding is that decoding of the dwg format is work in progress, so common sense would suggest to stick with an older (better decoded?) version as long as you don't loose information. I don't think that the 2013 format features new entities (at least none supported by BricsCAD), so I wonder why Bricsys chose this as the default save format...0 -
http://www.cadforum.cz/cadforum_en/command-history.asp
At the bottom it lists all the versions, and if you click on a version it tells you what was new in that version.0 -
It would be really nice if the warning message would perhaps list the items that are not going to be exported, or perhaps will be converted into another format (i.e. light weight plines are converted to regular plines)
Such a list would ideally provide a way to see or select those items. Perhaps add a button to select all those items, or if there is a list shown, the ability to select from the list one-by-one would be helpful so you could figure out what might be changed.
-Joe Dunfee0 -
@ Joe:
The problem may not be as straightforward as you think. There are for example non-graphical entities. And entities that are supported in an older version but that will loose some of their properties when saved to that version. Creating a list of all the information that is going to be lost may be possible, but many users would have great difficulty in interpreting and using such a list. What would the average user do with a list of 10,000 entities spread out over model space and, say, 25 layouts?
BTW:
Depending on the variable SAVEROUNDTRIP not all unsupported data will get lost in case of 'round-tripping'.0 -
Perhaps then a simpler approach might be for the report to list the types of entities that do exist in the current drawing, and what action BricsCAD will take. I imagine some entities are totally not supported and will simply be deleted, and others may be converted in some way. E.g. "This drawing contains 36 lightweight Plines that will be converted to a non-lightweight pline."
-Joe Dunfee0 -
@Anthony
That's a nice link, but it does not shed any light on file format changes.
And given the fact that the latest AutoCAD enhancements are seldom supported by Bricscad anyway, the question remains if you would really loose anything by saving to 2010 format in BriCAD 13 - or to put it the other way round - if saving to 2013 format does have any real advantage.0 -
The biggest issue is that this warning pops up, and you just don't have enough information to make a decision. Will anything actually be lost? If something will be lost, what parts of the drawing will be lost?
-Joe Dunfee0 -
@ Joe:
You can of course test the effects of saving to an older version by turning SAVEROUNDTRIP off before the operation and then reopening the file. As you hinted, in most cases data loss will take the form of a conversion from newer 'more advanced' entities to older 'dumber' entities. I think it is rare for graphical data to completely disappear. But in critical situations I would test the results of the operation.
Another example:
Create a table in V13.
SAVEASR12.
Result: The table has become an anonymous block. But the all the information in the table is still there.0 -
Actually, for the drawing I had in mind when conversion was an issue, it simply not viable to check two versions of a save to see what may be different. Comparing thousands of entities, one-by-one is really not viable. For that particular drawing, I knew the BOM tables would be the most important issue, and checked that, but there were other objects that I later realized were not translated, and didn't catch when I made it.
It is the unknown part of the equation that is troubling.
-Joe Dunfee0 -
Its amazing Autodesk has felt it was a good thing to evolve the dwg format without documentation like this.
Its like you better have a really good engine if you tell customers to only buy Ver 2012 gasoline and so on.
They have put themselves in a corner on this with Civil 3D as data lasts longer than acad versions. This idea of moving up and up is long worn out.
I suspect the same will happen with the dwg format. Now that I can port all my lisp and .net tools to bricscad, Autodesk has real competition. We can freeze the dwg format in place and start calling autodesk's files as "not trusted".
The lack of aec object enablers for bricscad only encourages me not to use them (civil 3d). Nothing like shooting yourself in the foot and bleeding your wrist at the same time.
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... but there were other objects that I later realized were not translated, and didn't catch when I made it.
Do you remember the type of object involved?0 -
Sorry it has been a while, so I don't recall many of the details. This was a drawing from a customer that needed to be translated to an older version.
There were some small tables that I originally assumed were simple text, that got exploded, and therefore were very hard to edit. But, I know there were some other objects. I knew there was some unknown stuff going on, but just didn't have the time to spend investigating the details. It was the unknown stuff that most troubled me.
-Joe Dunfee0 -
I can say I have been using the drawing dictionary, xrecords, and xdata since version 2002 of acad, and I believe that is how most developers store invisible data.
I have seen no changes along the way, so whatever you encounter entities not translating, its usually either exotic stuff you don't care about, or visible items like tables that you can easily investigate, although it would take time.
I honestly wonder if any one at Autodesk could answer the original post though. I bet you have to get many teams together to say what is really going on, as acad is a collection of parts that simply must adhere to some spec. Only each team would have the inner details of how they are doing something like making annotative text.
Classic example of this is watching Kean W's blog, where he routinely says things like "I wanted to see how such and such was implemented"... So even if you saw documentation that said what was destroyed during a conversion, would you trust it?
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The program doesn't seem to even do the most basic effort at checking what is not directly compatable with olderv ersions. Just saving an empty drawing as a 2010 DWG will cause a warning to appear that some entities are not supported in this 2010 version, and will not be saved.
-Joe Dunfee0
