P Retondo

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Posts posted by P Retondo


Raymond, no!! not the hole!!
We can't rely on screen representation of curves at high magnification. They aren't drawn perfectly accurately, and that can be proved, case in point. The magnification test shows lack of coincidence, my test shows perfect coincidence despite the apparent discrepancy on screen.
I use a test that does not rely on the uncertainties of screen representation at high magnification. My test relies instead on the underlying math. I join a line to the curve at any randomlyselected point, adjust it so that the line's length is a whole number (like 2.0000000000 inches). Then after overlaying the quarter arc on the oval, take away the oval and join again. It's easy to see if there is a difference. In this case, it's still 2.0000000000 inches, indicating coincidence at that point within VW's minimum tolerance. Now since that quarter arc is a bezier polyline, doesn't that suggest that the oval is also based on a bezier polyline?
Tomorrow in my abundant spare time I will perform a test on a locus with coordinates calculated from the oval's major and minor axes, and report what I observe.

PS, pdrake, you need to create a signature that has your VW version and OS so folks can know that to better understand your issue.

You need to convert to a polygon, then you will be able to add vertices. When you edit a rectangle and move a vertex, it automatically converts to a polygon. Or you can use the "Convert to polygons" tool. That's why you are seeing this behavior, which is normal.

Not sure what you mean by "it works after i move a vertex," but no handles probably means some kind of corruption. If just that object but not others in the file, then that object is corrupt. If the whole file, it may be corrupt. If all objects in all files, VW is corrupt.

First thing to do is close and restart VW.

Confirmed that the "quarter arc" does indeed do what Kevin says. The curve is identified in the OIP as a "polyline" and has, in the example I generated, 2 bezier control points. Proof positive, I think, that the "Oval" is not a true ellipse.
Kevin, since Rhino is NURBS based software, I'm not surprised that its version of an ellipse is just a bezier approximation, which is what I think you have confirmed.

It has been noted that when an "Oval" is trimmed, the resultant curves are polylines that don't exactly match the original oval's shape. Guessing that the "Oval" is generated from the equation for an ellipse with major and minor axes as parameters, this request is for an curve that would be a portion of an ellipse (=? oval), with control points at the end points and the 2 focii. The OIP could still display the lengths of the axes.

Raymond, that's pretty interesting. Did anyone from NNA confirm that their "Oval" is generated from an ellipse equation? That would dispose of all the doubt, but like you say it's pragmatically of zero consequence. I like the idea of a separate object type for a segment of an ellipse. Its control points could be the 2 focii, plus the endpoints.

It's more likely that I haven't any clue about mathHaha, not likely!
Here's the wikipedia on an "oval," in case you are interested:

Zoom, perhaps math definitions are different in Europe, but in the US a cylinder is sometimes considered the special case of a cone with infinite height, and any slanting section through a cone (or cylinder) that is closed (reaches from one side to another) is an ellipse. An ellipse in (x,y) coordinates has a quadratic equation similar to but more complicated than a circle, which, again, is a special type of ellipse where the 2 focii coincide.

Raymond, I initially had your thoughts, and I think we are 99% in agreement, except that there is an object type you don't mention germane to the question  the "Oval." Unlike an ellipse, the oval does not have a consensus mathematical definition, so I think it is telling that VW does not call their object an "Ellipse." What the VW "Oval" is I couldn't really say, and it may in mathematical definition be a bezier curve. So the fact that an Oval when trimmed becomes a series of polylines may not really represent a change of geometry. Donald, you originally raised this question, do you find that a line snapped to the oval becomes different in length when snapped to the trimmed curves?
Zoomer, funny! I assume you are tongue in cheek. Seriously, though, are we really moving to a design world in which forms which have been commonplace since the Renaissance are now to be shoved aside by the dictates of CAD engineers? That goes so much beyond the current discussion on precision it belongs in a different thread, but it's a big question, who is leading the development of CAD  designers or coders or marketers?
PS: I did the test. In my instance, I created a 3" line snapped to an oval. After trimming the oval, resulting in a polyline curve, and snapping the same line to that curve, it was shorter by 0.002248". This may have to do with the mathematical definition of a Bezier curve, which I don't have a completely firm grasp on despite having at least attempted to read Bezier's book. In my limited view, if you change the endpoint of a Bezier you may be unable to get the same shape regardless of how you tweak the Bezier parameters. Anyone know if this is true?
Sorry about the edits changing this post, that's the way the thought process works for me: on the other hand, if the "Oval" as defined by VW is in fact mathematically an ellipse, which has an equation defining every point, then there is no excuse for a clipped portion of that curve being mathematically different from the unclipped shape.

Raymond, respectfully disagree. Any set of points that can be defined mathematically can be represented equally well, in theory, by CAD. Apparently in this case NNA engineers have chosen not to write the code for a portion of any given ellipse. I have my doubts whether an obect of the VW type "oval" is a true ellipse, actually. From a pragmatic standpoint we are splitting hairs, no screen representation is exactly accurate, we are dealing with pixels and irrational numbers.

rD, I tried this in v2016, and the angle was correct: 9.462 degrees.

GWS, your signature says you're on 2013. I believe this issue might have been resolved in v2016.

christo, you've not given us a very clear idea of what is in the file you are working with. It's a wellknown shortcoming that the radius dimensioning tool often does not work in annotation space. If you have actual 2d arc elements on the design layer, you can get the dimensions there. I often have to redraw an arc over the referenced objects when in annotation space to get a radial dimension to work.
Based on limited testing, VW2016 seems to perform a lot better in this regard, maybe this has been fixed with the current version.
Here's something that may be a bug: If you extrude a circle, the radial dimensioning tool can pick up the radius from an extrude. If you extrude a polyline that consists in part of arcs, the tool can pick up the radius from the 2d object but not from the extrude.

+1 It may not be that difficult to do, if we are talking about extrudes, which are generated from a 2d shape in the first place. While we are at it, let's make it so that when an extrude is moved it's 2d primitive "moves" with it so that when editing the 2d shape, the vertices are aligned with the actual location of the 3d object. Why is that important? Say you have an extrude in a location, and you can, by snapping to points around it, create a new 2d object to modify the extrude. By doing a "cut" and "paste in place" into the extrude edit space, you would have your new geometry precisely and quickly. There are other workflows that would benefit greatly from these improvements. Combine the 2 improvements, and you could use the 2d editing tools directly on the shape of an extrude when in Top/Plan view.

There are so many occasions (at a corner, for example), when I wish there were an option to have unequal trim left and right on a window or door. If this could be implemented, the best way would be to have an "unequal" check box, which would then bring up data input for the 4 situations (actually, 8 would be ideal  left, right, top, bottom) without cluttering the usual OIP.

I'm sure I'm not alone in wishing it wasn't so easy to undock palettes. An errant mouse click and drag, and it's 30 seconds or so to get the darn thing to redock and to resize it. The solution would be an option to lock them, preferably using the same command used to lock a drawing object.
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I'm not sure if everyone posting here realizes that hybrid 2d/3d objects, such as walls, were the founding innovation of VectorWorks, then MiniCAD. When Richard Diehl launched this software, AutoCAD was far and away the dominant market player (it still is). There were a few startups in the CAD world that tried to tackle 3d, and I believe that VW and Archicad are the only real survivors. Revit came much later and was absorbed by Autodesk.
Back then, 2d drafting was the thing a CAD program HAD to do. The idea that an object could be both 2d and 3d held a lot of promise, and despite the glitches it's still a workhorse for us. If we want to convert something purely 3d to some kind of plan representation, getting the clip cube to work with fills and so that it can be viewported to a sheet is the best idea I've heard. I don't see any huge engineering hurdle there. But let's refine, not dismantle, the Top/Plan view.
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I use the eyedropper tool exactly as Josh does, and I can verify Josh and VG's complaint. Jonathan, I'm 99% sure this is not due to inadvertently hitting the "U" key, but as I haven't been able to pin down exactly when this problem occurs, I haven't filed a bug report. This behavior goes back at least to v2013. To clarify, with the eyedropper tool in "pick up attributes mode," I find that sometimes (not always) the default mode shifts to "put down attributes". I notice this when I ctrlclick on an object, expecting its attributes to be modified, and when that doesn't occur I notice that the default mode has switched from "pick up" to "put down." As I have used the "ctrl" hot key in such an instance, I have picked up attributes from the object, not put them down.
Again, Jim, if you're listening, this is the kind of boring, everyday problem we wish NNA would prioritize solving above glitzy new features. I attribute such problems to sloppy code.

I submitted a bug for this behavior, maybe a couple of years ago. At least I'm pretty sure I did, so many bug submits I can't remember them all. Anyway, never fixed, so just hit the "X" key to activate the selection tool before trying to activate the rotate tool, it's a habit by now.
Jim, whenever we say we would like VW to work with fewer glitches as a priority over new features, this is the kind of thing we are talking about.

Grant, I was unable to replicate this in v2015 or v2016. Something else must be going on with your file. When I group objects in an inactive layer, they are all reassigned to the active layer in a group also on the active layer.

+1 on the idea of scaleaware text and symbols for things like grid bubbles

MH, I don't think you are missing anything, I have the same problem. If someone has a solution I'd sure like to know what it is. Same problem often with arcs.
Geometry Errors
in General Discussion
Posted
Raymond, after talking with you and testing, I have discovered the source of my error, which causes us even more distress if we are concerned about accuracy and the integrity of the CAD calculation engine. I now agree that the VW "Oval" must be a true ellipse, and is probably generated from the algebraic ellipse equation ((x/a)^2 + (y/b)^2 = 1).
First, here was the source of my error, and without talking to Ray I would never have guessed. In my attempt to cause the calculation engine to reveal its secrets, I used two methods interchangeably: the join tool, whereby the program calculated the intersection between a line and a curve, and a snapping method, whereby I extended a line beyond the curve, and dragged it back to the "object/object" snap cursor. It turns out that those two methods give different results!! I believe in the case of an "Oval" that the "object/object" snap point does not actually lie on the oval curve (the difference in my test situation on a 2" wide oval was about 0.0003"  which could amount to feet on a large site oval).
I also verified Ray's method by calculating the coordinates of two random points on the ellipse (using the formula above) and placing loci there, and discovered that they exactly coincide. I tested the coincidence by creating a 1.0000000000" line horizontally from the locus, then joined that line to the oval, resulting in exactly the same length to 10 decimal places, the limits of VW accuracy.