Site Model problem

[Squiidly]

I'm trying to create a site model...for the first time. I brought in a tiff file created from a pdf, as the pdf brought into Architect was so fuzzy I couldn't read the information (why was that?). I then traced all the contours with the 2d polygon tool. Next I used the 'convert 2d to 3d poly' command. I then went to create the site model, entering all the information per the manual, and hit "enter". The color ball started spinning. and spinning. and spinning. I was either on acid or the program had frozen, and did a re-start. Went through the whole thing again. Same result, but this time I just went to bed to see if I would wake up to a spinning ball, and sure enough I did. 8 HOURS LATER! This can't be normal. Please advise.

Vectorworks 11.5, Mac G4

[CipesDesign]

I've been there. But I have also created DTM's successfully. Usually, when what describe occurs it is due to either poly's that overlap or are too convoluted (complex). Try this: in a new blank file, using the POLYLINE tool (in the second, 'curved' mode) draw six or seven "topo" lines. Make sure that none of them over lap any other and that none of them double back on themselves. Now do a select all, and go to TOOL>CONVERT TO POLYGONS. Next go to AEC>2D POLYS TO 3D CONTOURS. Follow the directions, changing the elevation of each line as it is highlighted, and continue clicking 'next' until there are no more lines. (You should notice at this point, that by single clicking on any of the 3d contour lines, in the OIP it will give you the "z" value of each. This is a good way to check that each of the polys is at the correct height in "z space"). Now go to AEC>SITE MODEL, set the parameters the way you want and click OK. You should now have a very simple DTM. Hope that works, and that it gives you some clues as to how to create a DTM from the real data!

[Squiidly]

I'll try what you suggested. I do have overlapping polygons, as there are existing site walls. How would these be described if there can't be "overlapping" contour lines? Offset them slightly?

[CipesDesign]

Yes, you could try that. I think I was told that lines cannot overlap at all. If you offset them slightly, then you could go back and use a wall (with some thickness) to cover up the slop. P

[Squiidly]

I did the simple model you suggested and it worked out fine. I'll redo the site model with non overlapping polygons and see if that helps. Thanks for your help.

[islandmon]

Whoa ... it doth appear that someone is 'drawing' instead of 'programming'. Site modeling is very specific as to the mathematics of closure.

1) Make sure the scan image matches the layer 'scale'. Normally one must re-scale the image to get line lengths to match.

2) Program your site survey & topo as a closure of vectors & arcs

using the tools described previously.