Converting 3d to useable 2d representations

[bcd]

This one has been gnawing for a long time:

Pre Maxon Rendering, if memory serves, Convert to Polygon - Hidden Line Rendering produced reliable and clean results.

Now, and for some time, the resulting conversion of all but the simplest objects produces an excessive mess of lines and polygons.

This creates several issues in practice eg:

• Auto Hybrids have excessively complex 2d components
• There are click points everywhere - with the result that clicking to the internal geometry is haphazard and imprecise
  
• 2d components of a Hybrid Symbol are chaotically fragmented or require significant clean up before they become usable.
  
• Computer performance is negatively affected when any significant number of such objects, which rely upon Convert to Polygon, are used
  
• Using the Bucket Fill(inner boundary) mode of the Polygon tool doesn't flood to the edges of an object as you would expect but to the edges of the closest small facet or fragment.
  
• File sizes are way too high, some PDF exports too complex and load times too long
  

This very powerful command has been been seriously depreciated. Can we have it back please?

eg:

consider this simple object from which Convert to Polygon produces 57 fragments, lines & facets rather than 3 simple Polygonal objects.

Edited October 17, 2015 by bcd

[Kevin McAllister]

The command needs to approach this a different way. Essentially what we want is the visible surfaces converted to NURBS and projected down onto the ground plane as 2d curves (ideally closed polylines).

It seems like its currently converting the visible surfaces to 3d polygons, then resetting their Z value to 0 and converting them to 2d.......

Kevin

[Kevin McAllister]

This is a serious weakness in my opinion. There is no way to create useable, low overhead 2d representations from 3d objects. VW relies on polygons which are inherently bad for 2d. I don't want a 2d "mesh" object. I want an efficient 2d closed polyline not a grouping of 2d polygons.

I want an easy way to convert the visible surfaces of a 3d object to a flattened 2d representation using clean, efficient polyline outlines. (The Extract tool should do this when asking for planar surfaces, the Auto-Hybrid should do this for the 2d portion, and there should be a menu command much like the other conversion commands - Convert to 2d Polyline in Hidden Line Mode.) See the attached image.

2d polygons should be relegated to specific workflows. No one wants a circle with 72 facets in a normal 3d-2d workflow. This method does not promote the accuracy desired in a CAD program. This is what you would expect in a visualization program (ie. C4D). Polylines and NURBS trump polygons for representing true shapes.

Kevin

[Benjamin Weill]

+111

It would be great if this function worked form different perspectives. The GP and then Section/elevation options.

[Art V]

+1

Any conversion that reduces the number of polygons with lots of vertices or avoids them completely by using polylines would be really useful as it keeps the file size and processing time down.

[PVA - Admin]

Agreed. This example shows a particularly nasty case where one would think it would be simple:

[img:center]https://techboard.vectorworks.net/ubbthreads.php?ubb=download&Number=13172&filename=Screen%20Shot%202015-10-19%20at%2011.12.28%20AM.png[/img]

[img:center]https://techboard.vectorworks.net/ubbthreads.php?ubb=download&Number=13173&filename=Screen%20Shot%202015-10-19%20at%2011.12.39%20AM.png[/img]

But you get something like this:

[img:center]https://techboard.vectorworks.net/ubbthreads.php?ubb=download&Number=13174&filename=Screen%20Shot%202015-10-19%20at%2011.12.53%20AM.png[/img]

It appears to be taking all 3d facets of the model and converting each of them individually to 2D polys, when it really should be focusing on the edges only. Not sure if this is something that should be changed on the "Convert to Polygons" tool directly, if it should be a prompt giving the user control over it, or if a different "Convert Edges to Polylines" command might make more sense. This thread will be included in the case.

[Art V]

Even if it would convert to polygons properly (i.e. 3 polygons) I suspect that because of the non-flat surfaces in the original there may be a lot of vertices to give an accurate outline, which might be worse than multiple polygon triangles.

What do you get if you merge the surfaces into a single polygon?

Though I agree that conversions could and should be more efficient to reduce overhead and other inconveniences (e.g. snapping issues) as much as possible.

Where possible I tend to create the 2D part of hybrid symbols myself, to keep it as simple as possible.

Edited October 19, 2015 by Art V

[PVA - Admin]

Merging these two threads, good feedback here that should be in the wishlist as well.

[Art V]

Jim,

When exchanging dwg files solid hatches often get imported as a triangulates polygon mesh (or mess). Could any improvement attempt in reducing polygonal clutter also take this into account?

It seems to me that it may work in that area too with a little bit of extra attention if that is something that can be controlled on VW's end (i.e. if it is not completely dependent on the ODA libraries).

[PVA - Admin]

Possibly, but I think that would be handled separately from this. Even though they functionally do the same sort of thing, the plugin that does 3D to poly conversion and the one that interprets DWGs are disparate.

[Art V]

Possibly, but I think that would be handled separately from this. Even though they functionally do the same sort of thing, the plugin that does 3D to poly conversion and the one that interprets DWGs are disparate.

Does this imply that polygonal clutter reduction code for 3D could more or less be copy/pasted into a 2D dwg import plugin for the dwg import with some adjustments?

I'm not a programmer, but if the programmers think this is more or less the case could you then make it a request for the dwg import plugin to have this functionality as well?

Especially with irregular shapes the number of polygon triangles can get nasty.

[PVA - Admin]

I really do not know enough about it to say, apologies, but I will indeed mention it.

[Art V]

Jim, no need to apologize, I know you are not a programmer. Thanks for mentioning it to the programmers.