willofmaine Posted February 9, 2007 Share Posted February 9, 2007 Until today, I've never been able to get a stake object to tell me the elevation of a given point on the DTM. Today it worked!... for a while. Now it doesn't work again. Even though in the Object Properties dialogue box I've selected "Set elev to site model," after the stake is placed, in the Object Info palette its mode is "Include as site model data." Any thoughts, anyone??! Thanks! -Will Quote Link to comment
willofmaine Posted February 9, 2007 Author Share Posted February 9, 2007 I just figured out why the stake objects worked for a bit. I had accidently updated the DTM, after which they were working. But in updating the DTM, the contours changed, and my 5' interval went from 105' to 104'11.999" !! When I revived an older model with the original site, the stake objects stopped working. So I deleted the DTM and re-created it from the original data. Now everything seems to work as expected, with the exception that the contours are different than before. Any thoughts would be appreciated... thanks. Quote Link to comment
islandmon Posted February 9, 2007 Share Posted February 9, 2007 The contours data resolution depends on the "Units" mantessa Preference. Reduce the decimal> "round to nearest" > 0.001 prior to updating the DTM. Quote Link to comment
willofmaine Posted February 9, 2007 Author Share Posted February 9, 2007 Thanks islandmon, but doesn't that simpy hide the problem? The problem being that when VectorWorks sees 5' as 4'11.999" I get a bit uncomfortable... Quote Link to comment
islandmon Posted February 10, 2007 Share Posted February 10, 2007 Give this a try: set the Unit preference to read-out only 0.0. Then, place a 2d locus randomly on the drawing. Write down the OIP coordinates of that loci... now... reset the Units preferences to 0.000000000. Are the OIP coordinates of that little 2d Locus exactly the same ? Quote Link to comment
willofmaine Posted February 10, 2007 Author Share Posted February 10, 2007 It depends. If I'm zoomed way out when I place the locus, then at 0.0 or 0.0000000 the results are the same. (I love that VW adjusts placement precision based on zoom, unlike some other softwares (won't mention any names...) where if you're a mile away and you randomly place something, it may have coordinates of 256ths of an inch! But I digress...). If I'm zoomed way in, then the 0.0 is rounded as expected, even though the number goes for as many digits as given when set to 0.000000000. What's very odd is that the model I've been working on, in having been recreated many times from the source data, is now giving me exact 5' contours (with units set to .001). But to do your experiment I copied the same source data (3d contours) into a brand new file and recreated a new model... with the 105' contour at 104'11.977" and 100' at 99'11.999"!! I had found that stake objects as source data were screwing up the DTM's contours, and I'd removed them all, and so until now I'd thought that that was the reason my 105' contours were now exact. But I guess not... Well, that's where I'm at... Thanks! -Will Quote Link to comment
ionw Posted February 13, 2007 Share Posted February 13, 2007 I have seen this same issue recently. I used the approch of changing the precision, as a thousandth didn't matter, but I agree that if something is a value, that VW doesn't approximate it.\ Quote Link to comment
willofmaine Posted February 14, 2007 Author Share Posted February 14, 2007 Here's where I'm at with Stake Objects and DTMs... Ion, thanks for concurring with me that VECTORworks should not confuse 5' with 4.9999999999'... But, at least to me, it's pretty impressive being able to take three-dimensional objects and so quickly generate contours from them.... I seem to have found that the representative contours of a DTM generated from 3D polygons, including source contours, respect the original source data. For example, assuming your source contours and DTM contours have the same interval, then the contours of both will be exactly the same. However, once a stake object (anywhere) is added, this 'respect' seems to become lost, and the DTM's contours may not match the source contours. This seems to result from flat triangles in the TIN that 'cut corners' and can flatten valleys, for example. It's as thought the DTM engine (or whatever it is) respects the lines of 3D polygons as well as the vertices, but once a stake is added, it only recognizes points and vertices, and triangulation becomes random...(?) Regarding the "Set elev to site model" mode for the stake object, I have found that the solution to getting it to work is simply updating the site model, regardless of whether or not any changes have been made to it... -Will Quote Link to comment
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