VW 2008 - fundamental dxf export/import problem persist

[jfitch]

I just installed my update of VW 2008, hoping it might help the rather basic export/import problems reported before.

No joy - same bugs exactly. I submitted the bug again through bug report, but I'm not sure if that is a black hole.

This is a very basic problem. If I can't depend on the export or import of a simple polygon with 5 vertices (2 simple radius, 1 bezier, two end points) then certainly anything even slightly complicated would be suspect. In fact all you seem to need to have is a bezier vertex between two corner vertices to have a serious problem as in the enclosed file.

OOPS - I guess I can't enclose the file because 2008 file extensions (.vwx) aren't allowed on the forum!!!

[jfitch]

Downloaded and installed SP1, same bugs still exist.

The silence on this one is deafening. Submitted as a bug, emailed tech@, no response.

[Ray Libby]

If you are referring to your original post of the file 175-Test.mcd, the main object is not a polygon but a polyline. If you convert the main object to a polygon the export seems to be fine. Then I took the original file, decomposed the main object and redrew the two right and left end polylines, composed the object then exported and it seemed fine again. Maybe there is something wrong (corrupt, not closed,??) with the two end polylines.

[Petri]

Can't reproduce. Of course, I can only import back to VW, but Beziers, fillets etc. seem to move quite nicely back and forth.

[Guest]

jfitch,

send the file and a description of the problem to me and I'll take a look at it.

By the way, I've added .vwx as a file format option to post here.

[jbrhwy]

I just tested 175-Test.mcd & just as jfitch stated not only do the vertex radii change, but the shape changes as well. See jpeg 175-Test.jpg.

[jfitch]

OK, here is a very simple shape, freshly drawn, which demonstrates the import problem. All you need to do is export it as .dxf, then import it again. You will see a substantial change in shape. Someone with access to the code should be able to exhaustively test this, there are only 5 vertices in the polyline. It is not corrupt, it is not a trick, it is not in the slightest bit unusual, and yet the error is profound.

However this one does not show the export problems which also exist. In the file posted in the original thread, the top line is exported as a curve with finite radius - at least that is how it is interpreted by a couple of 3rd party programs. Also the corner arcs are broken up into several curves of differing radii, leading to significant dimensional errors.

[Petri]

"The page cannot be found"

(I'd really like to get to the bottom of this. I deal a lot with landscape designers who use "funny shapes". This is worrying!)

[jbrhwy]

Petri

This problem has persisted for a very long time, I have reported it since 1998. A one occasion I laid out curbs for a road intersection incorrectly because of it! The problem with arc polylines are when the tangent of 1 curve is greater than 1/2 of the distance between the intersection points. The mid point created by Vectorworks does not allow this, therefore it changes the radius. The arc vertex mode was probably only intended as a corner fillet tool.

My work round is to add an additional vertex between the vertexes, very tedious process when you have closed polylines for pavement surfaces, curb & gutter, sidewalks & road right-of-way. Reversing curves are a nightmare. The swearing at VectorWorks & MiniCad programs is very intense when a intersection has to be revised.

What is needed is a vertex mode that places an arc between intersecting tangents by retaining the intersection point, ie like highway design & land surveying software.

[jfitch]

Yes, this problem has been around for a long time - at least since version 10, perhaps longer?

I have found a workaround for the simple polyline I posted: decompose the polyline first, then export the decomposed parts. This exports the components correctly, at least in a couple of simple test cases. Re-importing them also works correctly (though they must then be re-composed if you want the polyline back). Importing to a couple of 3rd party CAD/CAM apps appeared to work correctly as well. It isn't a great workaround for complex stuff, how do you know which things to decompose? However, since dxf doesn't seem to know much about the association anyway, maybe it works always.

In the first case I posted, the single polyline is split by the export into 5 lines and about 13 arcs and splines, none of them dimensionally correct. If you decompose the outline, you should get exactly 12 objects: 6 lines, 4 arcs of 1/4 radius, and two bezier polyline splines. Exporting the decomposed parts gets you exactly that in dxf. Why the export of the original polyline goes to all the trouble to split the corner arcs into three arcs of various radii (none of them correct) is a mystery. A bigger mystery is why the top line is made into an arc of large radius.

I have no idea why the exported polyline (converted to all the arcs and splines) gets re-imported so incorrectly. Most other CAD packages, including eDrawings and AutoDesk's own DWGViewer import correctly what was exported (albeit an incorrect shape due to the export problems).

I am using this to drive CNC machine tools which are accurate to a few ten-thousandths of an inch. Needless to say, the wild approximations made by the export produce unwanted results. I can't imagine why this isn't considered a priority 1 bug.

[jfitch]

Petri

The problem with arc polylines are when the tangent of 1 curve is greater than 1/2 of the distance between the intersection points. The mid point created by Vectorworks does not allow this, therefore it changes the radius. The arc vertex mode was probably only intended as a corner fillet tool.

This is also an annoying bug, but not the same thing? I have observed (and sworn at) the behavior you are talking about, and the only work around I have found for it is inserting intermediate corner vertices as you describe. However, in my example, that is not the problem, there are line segments between the corner radius arcs and the polyline bezier splines making up the curved ends, and plenty of room for the corner arcs to exist on their own. Might be related but I think they are two different bugs.

[Petri]

The problem with arc polylines are when the tangent of 1 curve is greater than 1/2 of the distance between the intersection points. The mid point created by Vectorworks does not allow this, therefore it changes the radius. The arc vertex mode was probably only intended as a corner fillet tool.

Ahh - I see.

[Guest]

Can you post a file to the original post, please? I don't see a file posted.

[jfitch]

Can you post a file to the original post, please? I don't see a file posted.

The original file is attached to the first post in the other thread. However I have attached another here (Test.vwx, the same one but without the holes, which are inconsequential). This demonstrates both the export and import problems.

If you export it and then re-import it, you will see very obvious problems. Not so obvious, but still serious problems can be observed by importing it into a 3rd party CAD package. I don't have a version of AutoCad that will let me analyze the shapes, but OneCNC reports that the shape now has 17 objects, none of them correct. The simple 1/4" radius corner arcs have been broken into three arcs of radii that vary from corner to corner. The top line has been exported as an arc or spline of about 6400 inches radius. The bottom line is still a line, but the length is incorrect. By eye, it looks like nearly the same shape, but dimensionally it is off in nearly every detail. As I stated before, if I decompose the shape before exporting, it imports back into VW, and into OneCNC correctly.

There is also a second file (Test2, the one I tried to post at the top of this thread) which has the minimum number of vertices to see the import problem. It does not appear to show the export problems though (the exported file imports into OneCNC correctly).

[jfitch]

I am worried that unless this is verified as a bug and a tracking number assigned, it will be ignored. Any news on it?

[Guest]

I am pretty sure I buglisted this. I'll double check a little later on.

[jfitch]

Katie, did this get listed as a bug? Still have heard nothing from tech.

[jfitch]

Now running SP2. All fundamental problems still exist, exactly as before.

Is anything every going to be done about this?

[Ricasha]

I am worried because I cant not export any section viewport , even I set all advanced parameters in Finite options.

I cant not any dwg export