Extra (invisible) stuff in a .dwg file ?

I'm working on an in-house program to automate the creation of some
drawings. It involves merging some small drawings (symbols) into a
larger one. I'm using .dxf files on both sides. All of the entities in
a small drawing are merged into the large one.

I was given a series of the small drawings that were created by our
in-house drafting people. A "normal" small drawing will contain 1 or 2
text strings, maybe 5 to 10 lines and perhaps a circle. However, many
of these files contain a multitude of text strings, lines, polylines,
arcs and circles. The odd thing is, all of this extra stuff is not
visible.

Our in-house guy (who knows a fair amount about Autocad) has done
everything he can think of to see and/or get rid of these extra
entities. He's verified that all layers are on; he's "purged" the
file. But they're still there.

Anyone have any idea what might be the issue here?

FWIW, we're using Autocad 2000. Also, if it means anything, some of
these symbol files were originally created back in the mid ninties
with R12 - others later on with R14.

 

Thanks. At your suggestion, I downloaded and tried the shareware
version of SuperPurge. Unfortunately, it didn't do anything more than
what the built-in Purge command did. The resulting file size and
number of objects in the drawing were the same in both cases.

What I have found to work is to "select" everything in the drawing and
copy it to a new drawing. The new drawing, then, is properly
structured. But, what a pain - I have a hundred and some of these to
go thru.

I don't understand how Autocad can fail to display all of this junk
and yet not generate some kind of error msg.

 

have you tried to erase "all" - remove selected window of visible stuff?

 

Can you be more specific about what you mean by "is not visible"?
What space?
What layer?
Are they zero-length?
Are they nested?
How do they appear in the dxf?

 

HiHo;
DXF out the file and read it to find out what you don't see.
???? How do you know something is there ?????

 

I am working with dxf files. That's how I know about all the extra
stuff being there.

I've written a program (in Visual Basic) that reads the dxf file and
generates a database of the objects that I'm interested in (lines,
text strings, polylines, arcs and circles). For each of these items,
I'm capturing several properties including the X and Y points. These
"extra" items all seem to be legitimate things. But when I open the
drawing in Autocad, and inspect the area of the drawing where an item
should be (based on its X and Y points) there's nothing there.

 

Martin,

I work with Terramodel, and process drawings sent to us by our
construction clients' consulting engineers. I see a lot of funny
stuff, and probably can tell you what those extra points are for.

These programs draw lines by making up "vertices" and joining them
with lines - the curvier the lines are, and/or the more segments that
went into drawing them, the more vertices you have.

In a dxf they look like points,(10-20-30) but are not. I forget what
the dxf differences are - have a look yourself and report back to us.

The biggest difference I need to make in the stuff I get from autocad
is in the elevations. People who are used to making 2D plans in
autocad do not place much importance on "points" & elevations, but boy
is it a mess when I want to make a terrain model to drive an automatic
bulldozer to.

I always get these text items with an elevation in text, and maybe two
crossed lines - no actual "point" and no actual "elevation". That's
when I write out a dxf (from terramodel), fix it up with a bit of
quickbasic code, then run it back in and place the points exactly
where I want them.

I can always tell when somebody is trying to learn that Land Desktop
thingee - thier elevations are either at sea level, or all over the
effing place. This is one - maybe the only - area where Terramodel is
way ahead of autocad.

- Tom

Happy Trails To You