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Purpose of rectangles

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Does anyone know what the purpose of rectangles are? I have been using VW for quite some time now (now 11.5) and have never found any unique properties associated with them. When I draw a rectangle, double clicking it causes an error notice - so I have to manually select Convert to Polygons to turn it into a polygon and turn it into a useful object (allowing both reshaping AND default basic properties of height and width).

Just wondering if there is a reason why it doesn't just create a polygon in the shape of a rectangle (or maybe I'm missing something quite fundamental).

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Rectangles can be edited via the Object Ino Palette. Single ckick to select, then modify the values (in the OIP) as desired. The big advantage in using rectabgles instead of poly's is that can be strectched horizontally or vertically without losing their "rectangularness", whereas stretching a poly, if not done carefully, can result in unwanted angular changes...

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When you rotate a rectangle it converts it into a polygon though, so there's no advantage. Even the rotated rectangle tool gives you a polygon, not a rectangle. You can still resize a polygon (stretching it horizontally or vertically) without it losing its rectangularness. And most importantly, you can reshape it.

The tool is useful. But the object type I think is superseded.

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Although not so critical today as it was 20 some years ago, back when computer memory and clock cycles were at an unholy premium, everything was designed to conserve space and run faster. OK, it's still true, but we're much more spoiled now.

The short of it is Rectangles take less memory to store then polygons. Like Lines, Rects only require two points to define, an UpperLeft and a LowerRight. PolyRects (my pseudo term) require four points. Yes, they are more flexible conceptually that Rects, but in the '80s and '90s, they were too expensive to consider replacing simple Rects.

Another not so obvious feature of Rects is their redraw speed versus other polygonal shapes. Graphics engines (the chips and software on video cards, and the like) have primitives for drawing lines and rectangles that are much faster than those used to draw other shapes. A program that was written to use Rects efficiently ran and refreshed the screen faster. It's still true today. Don't knock them, they really are useful, even if you don't see it directly.


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Another point to note;

The vast majority of architecture is (still) rectilinear in nature. Think of structural detailing; aside from roofs, mostly rectangles.

I use keyboard shortcuts as much as I can and find it quicker -for example, to draw a rectangle and rotate it to the right inclination for a rafter than to draw a poly or a rotated rectangle.

For the rest of normal detailing rectangles are much faster to draw than polys and can always be converted if you do happen to need to reshape them.



forgot to add: you don't need to doubleclick them to edit them that's a feature not a problem. :-) just Drag'nSnap or edit in the OIP.

[ 04-21-2005, 02:55 AM: Message edited by: propstuff ]

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Another reason is to still have standard, boring, plane rectangles is surely this day they require very little work to maintain the code. Indeed it would be more work to replace them than to keep them.

And remember polygon points need to store more than x and y values, but point types as well.

I don't think we should under-estimate the advantage of having simple primitives like rectangles, i mean i know the average file i deal with must have tens of thousands of them by the time you include all the ones in symbols and PIO. Doubling or more the data needed for that many items must knock the file size up and the speed down.

The situation is worse in the case of rounded rectangles, which when drawn by screen renderers like Apple's Quickdraw take 3 points of data, to do as a polygon take at least 8 points.

On saying this improving the function of standard rectangles so that if clicked with 2d reshape tool we where presented with a dialogue box asking if we would like the convert to polygon? OK/Cancel, instead of the standard "sorry dave i can't let you do that", that would be a good thing.

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And may I add that the Cartesian Grid is essentially rectilinear.

I often use rectangles to derive coordinate offsets. This avoids needing to do trig calcs for moves & dups. A quick rect from one object to the next gives me the X-Y move. Very quick ... clean and accurate. Rect is one of the least appreciated 'essential' tools.

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If you started out with a polyline, you can switch your 2D conversion res to low before changing it to a polygon, that will help a great deal.

In the industry series there is a "Filter 3D Polys" command which does exactly what you want, but I don't know of a 2D equivalent. In many cases it would be faster to convert to 3D, filter, and convert back to 2D than to delete vertices.

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I draw a lot of footings and when the engineer decides to change the size, resizing the rectangle is easy. If the footing is on the boundary - resize it from and end point, otherwise resize it from the centre - I think they're great. However rotated rectangles and ellipses should retain their shape, as I asked for in the wish list.

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I have a different experience with rectangles and rectangular polygons than some people have reported.

For one thing, both types of objects have center handles to drag with or snap to on my PC.

For another, I find that dragging either type of object with the Select tool to resize can't produce any angular changes (of course, reshaping a rectangular or any other polygon with the 2D Reshape tool can distort angles, but why use that if you want to keep it rectangular?).

I agree with those who've found it a nuisance to be unable to use the 2D Reshape tool on a newly created rectangle.

But, conversely, I can suggest one other advantage of the rectangle as a separate object type: in the Custom Selection command.

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