Mbuck Posted April 29, 2003 Share Posted April 29, 2003 I understand that VW Landmark does not important feature, which in many DTM packages is referred to as breaklines. Am I therefore correct in assuming that the ?Pad site modifier? is VW's equivalent. If this assumption is correct, then why in many cases am I seeing that such closed polygon site modifiers constraints are being ignored i.e. triangulation continues to cross this bounding constraint. Recently, for example I have a large site approx 9,000 data points but in the centre of the site there exists an old quarry (a deep hole 200 m in depth), which is obviously not developable land; and as such has no point data within that area. Although I have put a pad modifier around that area in an attempt to excise that portion of the site; when I generate a proposed contour the pad modifier boundary is largely being ignored, i.e. the DTM triangulation continues to cross this pad boundary. What condition(s) trigger this? Or is it a bug? If so would it not be more sensible to have another but more robust site modifier/constraint called a breakline which could achieve this end. Quote Link to comment
Vectorworks, Inc Employee Robert Anderson Posted April 29, 2003 Vectorworks, Inc Employee Share Posted April 29, 2003 Surround your pad modifier with a fence modifier. Quote Link to comment
Mbuck Posted April 30, 2003 Author Share Posted April 30, 2003 I assume that you mean a fence modifier that is coincident with the pad modifier. This I have tried on many previous occasions but the method always proves unsuccessful. Today, once again, as per your advice, I tried it with this much larger DTM and once again, as per my previous experience, it was unsuccessful -VW DTM algorithm(s) seems to get confuse and VW simply hangs requiring a restart. I suspect that the DTM module is trying to force a batter to be calculated between the fence and pad and because these entities are coincident it cannot calculate the transition; hence the need for a true breakline entity for future versions of VW. If you think this is not the case please let me know a possible alternative solution. Note that offsetting the modifiers will produce a batter between them, which in this case is not intended as one is in effect, trying to create an internal shear cliff face. Quote Link to comment
Vectorworks, Inc Employee Robert Anderson Posted April 30, 2003 Vectorworks, Inc Employee Share Posted April 30, 2003 Not exactly coincident -- it should be spaced out slightly (any small amount) from the pad modifier. Our DTM will not handle perfectly vertical faces. Quote Link to comment
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