I?m attempting to complete a residential design that is situated on a fairly steep lot with a lot of varying slopes, rock outcroppings and other topographic features. The design requires several slabs at varying heights, plus a sloping driveway. Some of the ?slabs? are discontinuous, so there?s no way to combine them all into one 3D solid to use as a modifier (one part of the site has to be excavated for landscaping, there?s a separate pad for the HVAC condensers at a different elevation, etc.) I?ve successfully generated a DTM from the DXF file my surveyor gave me, and I?ve been able to modify it, but only with mixed results.
The essential problem that I have is that the modifiers seem to cut into the hillside only around the perimeter of modifier, but the interior volume that should have been cut away is still mostly there. An example would be if I?d setup a square slab as a modifier and updated the DTM, I?d be left with something that looked (roughly) like a square shaped trench dug into the DTM (not a whole cube carved into the land). This seems particularly prone to happen with the roadway object I?m using for the driveway (I get little mountain peaks at roughly the height of the original DTM jumping out of the middle of the roadway). Other times I'll get what seems to be a perfectly normal cut, except there'll be one oddball point that peaks up.
The whole process is particularly maddening because it takes quite a while to update the DTM, then the only way to really see what?s going on accurately is to go render it with shadows? Probably time for a faster computer here.
Anyway, I?ve been experimenting a lot, and at this point I?m not sure if the things I?m trying are just superstitious on my part, but I could REALLY use some answers?
When creating multiple modifiers for a single DTM, do you draw one ?fence? line around the whole thing? Does anyone have any experience/tips when using multiple modifiers?
Exactly what class should the modifier objects (the 3d Polys) be? Exactly what class should the fence (the polyline boundary) be? Exactly what class should the DTM itself be?
Is there some ordering dependency for the DTM, the modifiers and the fence? Does the fence need to be ?in front of? the modifiers, and the modifiers ?in front of? the DTM?
When making changes, is it better to update the existing ?Proposed DTM? or to simply re-create the proposed DTM from the original site DTM?
For the modifiers and the fence line, are there any requirements in terms of fills? At one point I?d thought I?d got things working right when I made the fence poly-line solid, but now still no luck?
I know some of this is explicit in the manual, but I?ve had such a frustrating mixture of partial success and complete failure here? A complete understanding of what I?m doing wrong would be a huge help? I?m using VectorWorks 9.5.1 on a PC.
Thanks in advance,